You will find below the list of publications of all the members of the Peptides, Glycoconjugates and Metals in Biology research pole. For individual or theme-specific publications, please consult the research or the personal pages via the members list using the sidebar navigation tool.
2010 |
Controversies concerning the use of phytoestrogens in menopause management: Bioavailability and metabolism Article de journal P de Cremoux; P This; G Leclercq; Y Jacquot Maturitas, 65 (4), p. 334–339, 2010. @article{deCremoux:2010, title = {Controversies concerning the use of phytoestrogens in menopause management: Bioavailability and metabolism}, author = {P de Cremoux and P This and G Leclercq and Y Jacquot}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77649180155&doi=10.1016%2fj.maturitas.2009.12.019&partnerID=40&md5=00cf946c81c7de36df7368aa21940620}, doi = {10.1016/j.maturitas.2009.12.019}, year = {2010}, date = {2010-01-01}, journal = {Maturitas}, volume = {65}, number = {4}, pages = {334--339}, abstract = {It has been proposed that the use of phytoestrogens (PE) in menopausal therapy could be beneficial to woman health, particularly with respect to hot flushes. Indeed, PE may compensate the lack of endogenous 17β-estradiol occurring during menopause. However, therapeutic benefits remain questionable, as highlighted by recent publications. Indeed, data are often subjected to controversy since a number of exogenous and endogenous factors influencing the responsiveness of patients are not sufficiently taken into account. In the present paper, we will discuss the role of bioavailability and metabolism in the instability of individual response to PE. © 2009 Elsevier Ireland Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } It has been proposed that the use of phytoestrogens (PE) in menopausal therapy could be beneficial to woman health, particularly with respect to hot flushes. Indeed, PE may compensate the lack of endogenous 17β-estradiol occurring during menopause. However, therapeutic benefits remain questionable, as highlighted by recent publications. Indeed, data are often subjected to controversy since a number of exogenous and endogenous factors influencing the responsiveness of patients are not sufficiently taken into account. In the present paper, we will discuss the role of bioavailability and metabolism in the instability of individual response to PE. © 2009 Elsevier Ireland Ltd. All rights reserved. |
Cell biology meets biophysics to unveil the different mechanisms of penetratin internalization in cells Article de journal I D Alves; C -Y Jiao; S Aubry; B Aussedat; F Burlina; G Chassaing; S Sagan Biochimica et Biophysica Acta - Biomembranes, 1798 (12), p. 2231–2239, 2010. @article{Alves:2010, title = {Cell biology meets biophysics to unveil the different mechanisms of penetratin internalization in cells}, author = {I D Alves and C -Y Jiao and S Aubry and B Aussedat and F Burlina and G Chassaing and S Sagan}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958154973&doi=10.1016%2fj.bbamem.2010.02.009&partnerID=40&md5=1007ac53adbc935aa2b04c533a7e0670}, doi = {10.1016/j.bbamem.2010.02.009}, year = {2010}, date = {2010-01-01}, journal = {Biochimica et Biophysica Acta - Biomembranes}, volume = {1798}, number = {12}, pages = {2231--2239}, abstract = {Although cell-penetrating peptides are widely used as molecular devices to cross membranes and transport molecules or nanoparticles inside cells, the underlying internalization mechanism for such behavior is still studied and discussed. One of the reasons for such a debate is the wide panel of chemically different cell-penetrating peptides or cargo that is used. Indeed the intrinsic physico-chemical properties of CPP and conjugates strongly affect the cell membrane recognition and therefore the internalization pathways. Altogether, the mechanisms described so far should be shared between two general pathways: endocytosis and direct translocation. As it is established now that one cell-penetrating peptide can internalize at the same time by these two different pathways, the balance between the two pathways relies on the binding of the cell-penetrating peptide or conjugate to specific cell membrane components (carbohydrates, lipids). Like endocytosis which includes clathrin- and caveolae-dependent processes and macropinocytosis, different translocation mechanisms could co-exist, an idea that emerges from recent studies. In this review, we will focus solely on penetratin membrane interactions and internalization mechanisms. © 2010 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Although cell-penetrating peptides are widely used as molecular devices to cross membranes and transport molecules or nanoparticles inside cells, the underlying internalization mechanism for such behavior is still studied and discussed. One of the reasons for such a debate is the wide panel of chemically different cell-penetrating peptides or cargo that is used. Indeed the intrinsic physico-chemical properties of CPP and conjugates strongly affect the cell membrane recognition and therefore the internalization pathways. Altogether, the mechanisms described so far should be shared between two general pathways: endocytosis and direct translocation. As it is established now that one cell-penetrating peptide can internalize at the same time by these two different pathways, the balance between the two pathways relies on the binding of the cell-penetrating peptide or conjugate to specific cell membrane components (carbohydrates, lipids). Like endocytosis which includes clathrin- and caveolae-dependent processes and macropinocytosis, different translocation mechanisms could co-exist, an idea that emerges from recent studies. In this review, we will focus solely on penetratin membrane interactions and internalization mechanisms. © 2010 Elsevier B.V. |
Lipid domain separation, bilayer thickening and pearling induced by the cell penetrating peptide penetratin Article de journal A Lamazière; O Maniti; C Wolf; O Lambert; G Chassaing; G Trugnan; J Ayala-Sanmartin Biochimica et Biophysica Acta - Biomembranes, 1798 (12), p. 2223–2230, 2010. @article{Lamaziere:2010, title = {Lipid domain separation, bilayer thickening and pearling induced by the cell penetrating peptide penetratin}, author = {A Lamazi\`{e}re and O Maniti and C Wolf and O Lambert and G Chassaing and G Trugnan and J Ayala-Sanmartin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958115870&doi=10.1016%2fj.bbamem.2009.12.024&partnerID=40&md5=5c0c8337f57ee0a5797bfd4d21d56479}, doi = {10.1016/j.bbamem.2009.12.024}, year = {2010}, date = {2010-01-01}, journal = {Biochimica et Biophysica Acta - Biomembranes}, volume = {1798}, number = {12}, pages = {2223--2230}, abstract = {Protein membrane transduction domains are able to translocate through cell membranes. This capacity resulted in new concepts on cell communication and in the design of vectors for internalization of active molecules into cells. Penetratin crosses the plasma membrane by a receptor and metabolic energy-independent mechanism which is at present unknown. A better knowledge of its interaction with phospholipids will help to understand the molecular mechanisms of cell penetration. Here, we investigated the role of lipid composition on penetratin induced membrane perturbations by X-ray diffraction, microscopy and 31P-NMR. Penetratin showed the ability to induce phospholipid domain separation, membrane bilayer thickening, formation of vesicles, membrane undulations and tubular pearling. These data demonstrate its capacity to increase membrane curvature and suggest that dynamic phospholipid-penetratin complexes can be organized in different structural arrangements. These properties and their implications in peptide membrane translocation capacity are discussed. © 2009 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Protein membrane transduction domains are able to translocate through cell membranes. This capacity resulted in new concepts on cell communication and in the design of vectors for internalization of active molecules into cells. Penetratin crosses the plasma membrane by a receptor and metabolic energy-independent mechanism which is at present unknown. A better knowledge of its interaction with phospholipids will help to understand the molecular mechanisms of cell penetration. Here, we investigated the role of lipid composition on penetratin induced membrane perturbations by X-ray diffraction, microscopy and 31P-NMR. Penetratin showed the ability to induce phospholipid domain separation, membrane bilayer thickening, formation of vesicles, membrane undulations and tubular pearling. These data demonstrate its capacity to increase membrane curvature and suggest that dynamic phospholipid-penetratin complexes can be organized in different structural arrangements. These properties and their implications in peptide membrane translocation capacity are discussed. © 2009 Elsevier B.V. |
Sugars to control ligand shape in metal complexes: Conformationally constrained glycoligands with a predetermination of stereochemistry and a structural control Article de journal L Garcia; S Maisonneuve; J Xie; R Guillot; P Dorlet; E Rivière; M Desmadril; F Lambert; C Policar Inorganic Chemistry, 49 (16), p. 7282–7288, 2010. @article{Garcia:2010, title = {Sugars to control ligand shape in metal complexes: Conformationally constrained glycoligands with a predetermination of stereochemistry and a structural control}, author = {L Garcia and S Maisonneuve and J Xie and R Guillot and P Dorlet and E Rivi\`{e}re and M Desmadril and F Lambert and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955475481&doi=10.1021%2fic1002379&partnerID=40&md5=d7e719000261dc5be94c8bbf72ce40ca}, doi = {10.1021/ic1002379}, year = {2010}, date = {2010-01-01}, journal = {Inorganic Chemistry}, volume = {49}, number = {16}, pages = {7282--7288}, abstract = {In coordination chemistry, ligand shape can be used to tune properties, such as metal selectivity, coordination number, electronic structure, redox potential, and metal center stereochemistry including coordination helicates formation, and also to generate cavities for encapsulation. The results presented in this article indicate that two epimeric glycoligands (3 and 4) based on the conformationally restrained xylo-and ribo-1,2-O- isopropylidenefurano scaffolds are preorganized in water through π-π stacking due to hydrophobic interactions, as evidenced from excimer observation. The structure obtained in the solid state for one of the Cu(II) complexes (5) is chiral, with an original helical chirality arising from the coiling of the two ligands around the Cu-Cu axis. It shows an unusual double-deck type structure, with π-π interaction between two triazoyl-pyridyl rings and with a small cavity between the two Cu(II) ions able to host a bridging water molecule, as suggested by electron paramagnetic resonance. The Cu(II) complex from the epimeric ligand (6) shows similar properties with a mirror-image CD spectrum in the d-d region of the Cu(II). There is a predetermination of chirality at the metal center by the glycoligand induced by the C3 configuration, 6 and 5 being pseudoenantiomers. Interestingly, the stereochemistry at the metal center is here controlled by the combination of π-stacking and chiral backbone. © 2010 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In coordination chemistry, ligand shape can be used to tune properties, such as metal selectivity, coordination number, electronic structure, redox potential, and metal center stereochemistry including coordination helicates formation, and also to generate cavities for encapsulation. The results presented in this article indicate that two epimeric glycoligands (3 and 4) based on the conformationally restrained xylo-and ribo-1,2-O- isopropylidenefurano scaffolds are preorganized in water through π-π stacking due to hydrophobic interactions, as evidenced from excimer observation. The structure obtained in the solid state for one of the Cu(II) complexes (5) is chiral, with an original helical chirality arising from the coiling of the two ligands around the Cu-Cu axis. It shows an unusual double-deck type structure, with π-π interaction between two triazoyl-pyridyl rings and with a small cavity between the two Cu(II) ions able to host a bridging water molecule, as suggested by electron paramagnetic resonance. The Cu(II) complex from the epimeric ligand (6) shows similar properties with a mirror-image CD spectrum in the d-d region of the Cu(II). There is a predetermination of chirality at the metal center by the glycoligand induced by the C3 configuration, 6 and 5 being pseudoenantiomers. Interestingly, the stereochemistry at the metal center is here controlled by the combination of π-stacking and chiral backbone. © 2010 American Chemical Society. |
NMR structure of a viral peptide inserted in artificial membranes: A view on the early steps of the birnavirus entry process Article de journal M Galloux; S Libersou; I D Alves; R Marquant; G F Salgado; H Rezaei; J Lepault; B Delmas; S Bouaziz; N Morellet Journal of Biological Chemistry, 285 (25), p. 19409–19421, 2010. @article{Galloux:2010, title = {NMR structure of a viral peptide inserted in artificial membranes: A view on the early steps of the birnavirus entry process}, author = {M Galloux and S Libersou and I D Alves and R Marquant and G F Salgado and H Rezaei and J Lepault and B Delmas and S Bouaziz and N Morellet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953497972&doi=10.1074%2fjbc.M109.076083&partnerID=40&md5=c9d96ac7e0af5e3bde71c350f97cf790}, doi = {10.1074/jbc.M109.076083}, year = {2010}, date = {2010-01-01}, journal = {Journal of Biological Chemistry}, volume = {285}, number = {25}, pages = {19409--19421}, abstract = {Nonenveloped virus must penetrate the cellular membrane to access the cytoplasm without the benefit of membrane fusion. For birnavirus, one of the peptides present in the virus capsid, pep46 for infectious bursal disease virus, is able to induce pores into membranes as an intermediate step of the birnavirus-penetration pathway. Using osmotic protection experiments, we demonstrate here that pep46 and its pore-forming N-terminal moiety (pep22) form pores of different diameters, 5-8 and 2-4 nm, respectively, showing that both pep46 moieties participate to pore formation. The solution structures of pep46, pep22, and pep24 (the pep46 C-terminal moiety) in different hydrophobic environments and micelles determined by 1H NMR studies provide structural insights of the pep46 domain interaction. In CDCl3/CD 3OH mixture and in dodecylphosphocholine micelles, the N-terminal domain of pep46 is structured in a long kinked helix, although theCterminus is structured in one or two helices depending upon the solvents used.Wealso show that the folding and the proline isomerization status of pep46 depend on the type of hydrophobic environment. NMR spectroscopy with labeled phospholipid micelles, differential scanning calorimetry, and plasmon waveguide resonance studies show the peptides lie parallel to the lipid-water interface, perturbing the fatty acid chain packing. All these data lead to a model in which the two domains of pep46 interact with the membrane to form pores. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nonenveloped virus must penetrate the cellular membrane to access the cytoplasm without the benefit of membrane fusion. For birnavirus, one of the peptides present in the virus capsid, pep46 for infectious bursal disease virus, is able to induce pores into membranes as an intermediate step of the birnavirus-penetration pathway. Using osmotic protection experiments, we demonstrate here that pep46 and its pore-forming N-terminal moiety (pep22) form pores of different diameters, 5-8 and 2-4 nm, respectively, showing that both pep46 moieties participate to pore formation. The solution structures of pep46, pep22, and pep24 (the pep46 C-terminal moiety) in different hydrophobic environments and micelles determined by 1H NMR studies provide structural insights of the pep46 domain interaction. In CDCl3/CD 3OH mixture and in dodecylphosphocholine micelles, the N-terminal domain of pep46 is structured in a long kinked helix, although theCterminus is structured in one or two helices depending upon the solvents used.Wealso show that the folding and the proline isomerization status of pep46 depend on the type of hydrophobic environment. NMR spectroscopy with labeled phospholipid micelles, differential scanning calorimetry, and plasmon waveguide resonance studies show the peptides lie parallel to the lipid-water interface, perturbing the fatty acid chain packing. All these data lead to a model in which the two domains of pep46 interact with the membrane to form pores. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc. |
Primary photodynamics of a biomimetic model of photoactive yellow protein (PYP) Article de journal P Changenet-Barret; C Loukou; C Ley; F Lacombat; P Plaza; J -M Mallet; M M Martin Physical Chemistry Chemical Physics, 12 (41), p. 13715–13723, 2010. @article{Changenet-Barret:2010, title = {Primary photodynamics of a biomimetic model of photoactive yellow protein (PYP)}, author = {P Changenet-Barret and C Loukou and C Ley and F Lacombat and P Plaza and J -M Mallet and M M Martin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958081983&doi=10.1039%2fc0cp00618a&partnerID=40&md5=0b3a7b924d2dd264329853df721e4248}, doi = {10.1039/c0cp00618a}, year = {2010}, date = {2010-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {12}, number = {41}, pages = {13715--13723}, abstract = {The present work aims at characterizing the photophysical behavior of a first biomimetic cyclodextrin model (CD-PYP1) of the photoactive site of photoactive yellow protein (PYP). The hydrophobic cyclodextrin cavity in which the chromophore self-includes, mimics its local environment within the protein. The photoinduced behavior of deprotonated CD-PYP1 (dp-CD-PYP1) has been probed by femtosecond transient-absorption spectroscopy and compared to those of the free deprotonated chromophore (pCT−) and of wild-type PYP. The excited-state deactivation of dp-CD-PYP1 is found to be non-exponential, with slower time components and higher quantum yield of fluorescence than pCT−. Like in PYP, the non-exponential decay is attributed to ground-state structural heterogeneities of the self-inclusion complexes. A long-lived photoproduct is observed in the transient spectra of dp-CD-PYP1 and identified as the cis isomer. The isomerization quantum yield of dp-CD-PYP1 is estimated to be about 4%, in contrast with the free chromophore in solution which does not photoisomerize at all. This demonstrates the active role of the cyclodextrin environment to promote the photoisomerization of the chromophore, as is thought to be the case for wild-type PYP. The effects of chromophore inclusion in the cyclodextrin on the photoinduced processes are rationalized within the framework of recent theoretical calculations involving two competitive deactivation channels: (i) trans to cis isomerization and (ii) rotation of the phenolate group, leading to trans ground-state recovery. Inclusion is proposed to favor isomerization by hindering the rotation of the phenolate group. Optimizing the structure of this first model in order to better reproduce the primary photoresponse of PYP thus appears very promising. © the Owner Societies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The present work aims at characterizing the photophysical behavior of a first biomimetic cyclodextrin model (CD-PYP1) of the photoactive site of photoactive yellow protein (PYP). The hydrophobic cyclodextrin cavity in which the chromophore self-includes, mimics its local environment within the protein. The photoinduced behavior of deprotonated CD-PYP1 (dp-CD-PYP1) has been probed by femtosecond transient-absorption spectroscopy and compared to those of the free deprotonated chromophore (pCT−) and of wild-type PYP. The excited-state deactivation of dp-CD-PYP1 is found to be non-exponential, with slower time components and higher quantum yield of fluorescence than pCT−. Like in PYP, the non-exponential decay is attributed to ground-state structural heterogeneities of the self-inclusion complexes. A long-lived photoproduct is observed in the transient spectra of dp-CD-PYP1 and identified as the cis isomer. The isomerization quantum yield of dp-CD-PYP1 is estimated to be about 4%, in contrast with the free chromophore in solution which does not photoisomerize at all. This demonstrates the active role of the cyclodextrin environment to promote the photoisomerization of the chromophore, as is thought to be the case for wild-type PYP. The effects of chromophore inclusion in the cyclodextrin on the photoinduced processes are rationalized within the framework of recent theoretical calculations involving two competitive deactivation channels: (i) trans to cis isomerization and (ii) rotation of the phenolate group, leading to trans ground-state recovery. Inclusion is proposed to favor isomerization by hindering the rotation of the phenolate group. Optimizing the structure of this first model in order to better reproduce the primary photoresponse of PYP thus appears very promising. © the Owner Societies. |
2009 |
Characterization and Scintillation Properties of Sol–Gel Derived Lu2SiO5:Ln3+ (Ln=Ce, Eu and Tb) Powders Article de journal C Mansuy; C Dujardin; R Mahiou; J M Nedelec Optical Materials, 31 (9), p. 1334-1336, 2009. @article{Mansuy:2009, title = {Characterization and Scintillation Properties of Sol\textendashGel Derived Lu2SiO5:Ln3+ (Ln=Ce, Eu and Tb) Powders}, author = {C Mansuy and C Dujardin and R Mahiou and J M Nedelec}, doi = {10.1016/j.optmat.2008.10.008}, year = {2009}, date = {2009-04-01}, journal = {Optical Materials}, volume = {31}, number = {9}, pages = {1334-1336}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Synthesis of N-Functionalized 2,2$'$-Dipyridylamine Ligands, Complexation to Ruthenium (II) and Anchoring of Complexes to Papain from Papaya Latex Article de journal Pierre Haquette; Blaise Dumat; Barisa Talbi; Shararé Arbabi; Jean-Luc Renaud; Gérard Jaouen; Mich`ele Salmain Journal of Organometallic Chemistry, 694 (6), p. 937-941, 2009. @article{Haquette:2009, title = {Synthesis of N-Functionalized 2,2$'$-Dipyridylamine Ligands, Complexation to Ruthenium (II) and Anchoring of Complexes to Papain from Papaya Latex}, author = {Pierre Haquette and Blaise Dumat and Barisa Talbi and Sharar\'{e} Arbabi and Jean-Luc Renaud and G\'{e}rard Jaouen and Mich{`e}le Salmain}, doi = {10.1016/j.jorganchem.2008.11.052}, year = {2009}, date = {2009-03-01}, journal = {Journal of Organometallic Chemistry}, volume = {694}, number = {6}, pages = {937-941}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Wrapping nanocrystals with an amphiphilic polymer preloaded with fixed amounts of fluorophore generates FRET-based nanoprobes with a controlled donor/acceptor ratio Article de journal A V Yakovlev; F Zhang; A Zulqurnain; A Azhar-Zahoor; C Luccardini; S Gaillard; J -M Mallet; P Tauc; J -C Brochon; W J Parak; A Feltz; M Oheim Langmuir, 25 (5), p. 3232–3239, 2009. @article{Yakovlev:2009, title = {Wrapping nanocrystals with an amphiphilic polymer preloaded with fixed amounts of fluorophore generates FRET-based nanoprobes with a controlled donor/acceptor ratio}, author = {A V Yakovlev and F Zhang and A Zulqurnain and A Azhar-Zahoor and C Luccardini and S Gaillard and J -M Mallet and P Tauc and J -C Brochon and W J Parak and A Feltz and M Oheim}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-65249166887&doi=10.1021%2fla8038347&partnerID=40&md5=79e21af7f8910b971d649af8000047b1}, doi = {10.1021/la8038347}, year = {2009}, date = {2009-01-01}, journal = {Langmuir}, volume = {25}, number = {5}, pages = {3232--3239}, abstract = {Colloidal nanocrystal (NC) donors wrapped with a polymer coating including multiple organic acceptor molecules are promising scaffolds for fluorescence resonance energy transfer (FRET)-based nanobiosensors. Over other self-assembling donor - acceptor configurations, our preloaded polymers have the virtue of producing compact assemblies with a fixed donor/acceptor distance. This property, together with the possibility of stoichiometric polymer loading, allowed us to directly address how the FRET efficiency depended on the donor/acceptor. At the population level, nanoprobes based on commercial as well as custom CdSe/ZnS donors displayed the expected dose-dependent rise in transfer efficiency, saturating from about five ATTO dyes/NC. However, for a given acceptor concentration, both the intensity and lifetime of single-pair FRET data revealed a large dispersion of transfer efficiencies, highlighting an important heterogeneity among nominally identical FRET-based nanoprobes. Rigorous quality check during synthesis and shell assembly as well as postsynthesis sorting and purification are required to make hybrid semiconductor - organic nanoprobes a robust and viable alternative to organic or genetically encoded nanobiosensors. © Copyright 2009 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Colloidal nanocrystal (NC) donors wrapped with a polymer coating including multiple organic acceptor molecules are promising scaffolds for fluorescence resonance energy transfer (FRET)-based nanobiosensors. Over other self-assembling donor - acceptor configurations, our preloaded polymers have the virtue of producing compact assemblies with a fixed donor/acceptor distance. This property, together with the possibility of stoichiometric polymer loading, allowed us to directly address how the FRET efficiency depended on the donor/acceptor. At the population level, nanoprobes based on commercial as well as custom CdSe/ZnS donors displayed the expected dose-dependent rise in transfer efficiency, saturating from about five ATTO dyes/NC. However, for a given acceptor concentration, both the intensity and lifetime of single-pair FRET data revealed a large dispersion of transfer efficiencies, highlighting an important heterogeneity among nominally identical FRET-based nanoprobes. Rigorous quality check during synthesis and shell assembly as well as postsynthesis sorting and purification are required to make hybrid semiconductor - organic nanoprobes a robust and viable alternative to organic or genetically encoded nanobiosensors. © Copyright 2009 American Chemical Society. |
Lipid reorganization induced by membrane-active peptides probed using differential scanning calorimetry Article de journal P Joanne; C Galanth; N Goasdoué; P Nicolas; S Sagan; S Lavielle; G Chassaing; C El Amri; I D Alves Biochimica et Biophysica Acta - Biomembranes, 1788 (9), p. 1772–1781, 2009. @article{Joanne:2009a, title = {Lipid reorganization induced by membrane-active peptides probed using differential scanning calorimetry}, author = {P Joanne and C Galanth and N Goasdou\'{e} and P Nicolas and S Sagan and S Lavielle and G Chassaing and C El Amri and I D Alves}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68749107071&doi=10.1016%2fj.bbamem.2009.05.001&partnerID=40&md5=7418f400cf2f7b97c3567f4e976485ff}, doi = {10.1016/j.bbamem.2009.05.001}, year = {2009}, date = {2009-01-01}, journal = {Biochimica et Biophysica Acta - Biomembranes}, volume = {1788}, number = {9}, pages = {1772--1781}, abstract = {The overlapping biological behaviors between some cell penetrating peptides (CPPs) and antimicrobial peptides (AMPs) suggest both common and different membrane interaction mechanisms. We thus explore the capacity of selected CPPs and AMPs to reorganize the planar distribution of binary lipid mixtures by means of differential scanning calorimetry (DSC). Additionally, membrane integrity assays and circular dichroism (CD) experiments were performed. Two CPPs (Penetratin and RL16) and AMPs belonging to the dermaseptin superfamily (Drs B2 and C-terminal truncated analog [1-23]-Drs B2 and two plasticins DRP-PBN2 and DRP-PD36KF) were selected. Herein we probed the impact of headgroup charges and acyl chain composition (length and unsaturation) on the peptide/lipid interaction by using binary lipid mixtures. All peptides were shown to be α-helical in all the lipid mixtures investigated, except for the two CPPs and [1-23]-Drs B2 in the presence of zwitterionic lipid mixtures where they were rather unstructured. Depending on the lipid composition and peptide sequence, simple binding to the lipid surface that occur without affecting the lipid distribution is observed in particular in the case of AMPs. Recruitments and segregation of lipids were observed, essentially for CPPs, without a clear relationship between peptide conformation and their effect in the lipid lateral organization. Nonetheless, in most cases after initial electrostatic recognition between the peptide charged amino acids and the lipid headgroups, the lipids with the lowest phase transition temperature were selectively recruited by cationic peptides while those with the highest phase transition were segregated. Membrane activities of CPPs and AMPs could be thus related to their preferential interactions with membrane defects that correspond to areas with marked fluidity. Moreover, due to the distinct membrane composition of prokaryotes and eukaryotes, lateral heterogeneity may be differently affected by cationic peptides leading to either uptake or/and antimicrobial activities. © 2009 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The overlapping biological behaviors between some cell penetrating peptides (CPPs) and antimicrobial peptides (AMPs) suggest both common and different membrane interaction mechanisms. We thus explore the capacity of selected CPPs and AMPs to reorganize the planar distribution of binary lipid mixtures by means of differential scanning calorimetry (DSC). Additionally, membrane integrity assays and circular dichroism (CD) experiments were performed. Two CPPs (Penetratin and RL16) and AMPs belonging to the dermaseptin superfamily (Drs B2 and C-terminal truncated analog [1-23]-Drs B2 and two plasticins DRP-PBN2 and DRP-PD36KF) were selected. Herein we probed the impact of headgroup charges and acyl chain composition (length and unsaturation) on the peptide/lipid interaction by using binary lipid mixtures. All peptides were shown to be α-helical in all the lipid mixtures investigated, except for the two CPPs and [1-23]-Drs B2 in the presence of zwitterionic lipid mixtures where they were rather unstructured. Depending on the lipid composition and peptide sequence, simple binding to the lipid surface that occur without affecting the lipid distribution is observed in particular in the case of AMPs. Recruitments and segregation of lipids were observed, essentially for CPPs, without a clear relationship between peptide conformation and their effect in the lipid lateral organization. Nonetheless, in most cases after initial electrostatic recognition between the peptide charged amino acids and the lipid headgroups, the lipids with the lowest phase transition temperature were selectively recruited by cationic peptides while those with the highest phase transition were segregated. Membrane activities of CPPs and AMPs could be thus related to their preferential interactions with membrane defects that correspond to areas with marked fluidity. Moreover, due to the distinct membrane composition of prokaryotes and eukaryotes, lateral heterogeneity may be differently affected by cationic peptides leading to either uptake or/and antimicrobial activities. © 2009 Elsevier B.V. All rights reserved. |
Identification of a human estrogen receptor α-derived antiestrogenic peptide that adopts a polyproline II conformation Article de journal J Kapitán; D Gallo; N Goasdoué; M Nicaise; M Desmadril; L Hecht; G Leclerq; L D Barron; Y Jacquot Journal of Peptide Science, 15 (7), p. 455–464, 2009. @article{Kapitan:2009, title = {Identification of a human estrogen receptor α-derived antiestrogenic peptide that adopts a polyproline II conformation}, author = {J Kapit\'{a}n and D Gallo and N Goasdou\'{e} and M Nicaise and M Desmadril and L Hecht and G Leclerq and L D Barron and Y Jacquot}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67849121678&doi=10.1002%2fpsc.1136&partnerID=40&md5=ae2b70e1b0c53be7d43e9ac75a027089}, doi = {10.1002/psc.1136}, year = {2009}, date = {2009-01-01}, journal = {Journal of Peptide Science}, volume = {15}, number = {7}, pages = {455--464}, abstract = {Polyproline II (PPII) helix is an extended secondary structure present in a number of proteins. PPII-containing sequences mediate specific protein-protein interactions with partners containing appropriate cognate domains called PPII-recognizing domains (PRDs) and are involved in the activation of intracellular signaling pathways. Thus, the identification of PPII structures in proteins is of great interest, not only to explore molecular and physiological mechanisms, but also to elaborate new potential drugs. By revisiting X-ray crystal structures of liganded α-type human estrogen receptor (ERα), we have identified an 11-residue PPII-helical sequence (D321AEPPILYSEY331) in the ligand-binding domain of the receptor. The data recorded by far-ultraviolet circular dichroism (far-UV CD), vibrational Raman optical activity (ROA) and differential scanning calorimetry (DSC) show that the corresponding peptide (Ac-DAEPPILYSEY-NH2) is particularly well structured in PPII, with the same proportion of PPII as observed from X-ray structures (∼85%). In addition, studies carried out on ERα-negative Evsa-T breast cancer cells transiently co-transfected with a pcDNA3-ERα plasmid and a Vit-tk-Luc reporter gene revealed that the peptide antagonizes the estradiol-induced transcription providing perspectives for researching new molecules with antagonistic properties. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polyproline II (PPII) helix is an extended secondary structure present in a number of proteins. PPII-containing sequences mediate specific protein-protein interactions with partners containing appropriate cognate domains called PPII-recognizing domains (PRDs) and are involved in the activation of intracellular signaling pathways. Thus, the identification of PPII structures in proteins is of great interest, not only to explore molecular and physiological mechanisms, but also to elaborate new potential drugs. By revisiting X-ray crystal structures of liganded α-type human estrogen receptor (ERα), we have identified an 11-residue PPII-helical sequence (D321AEPPILYSEY331) in the ligand-binding domain of the receptor. The data recorded by far-ultraviolet circular dichroism (far-UV CD), vibrational Raman optical activity (ROA) and differential scanning calorimetry (DSC) show that the corresponding peptide (Ac-DAEPPILYSEY-NH2) is particularly well structured in PPII, with the same proportion of PPII as observed from X-ray structures (∼85%). In addition, studies carried out on ERα-negative Evsa-T breast cancer cells transiently co-transfected with a pcDNA3-ERα plasmid and a Vit-tk-Luc reporter gene revealed that the peptide antagonizes the estradiol-induced transcription providing perspectives for researching new molecules with antagonistic properties. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. |
In-source fragmentation of very labile peptides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry Article de journal E Sachon; G Clodic; T Blasco; Y Jacquot; G Bolbach Analytical Chemistry, 81 (21), p. 8986–8992, 2009. @article{Sachon:2009a, title = {In-source fragmentation of very labile peptides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry}, author = {E Sachon and G Clodic and T Blasco and Y Jacquot and G Bolbach}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350639277&doi=10.1021%2fac901449d&partnerID=40&md5=0855ca933862f5a5e1d90def7d28dd10}, doi = {10.1021/ac901449d}, year = {2009}, date = {2009-01-01}, journal = {Analytical Chemistry}, volume = {81}, number = {21}, pages = {8986--8992}, abstract = {Synthetic acidic proline-rich peptides devoid of basic chemical groups were studied by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). Their ion mass spectra recorded in reflector positive ion mode have shown unusual features, i.e., absence or very weak presence of protonated peptide together with a major peak associated with fragmentation at a site that corresponds to the amide bond N-terminal to the first proline of the XPP motif. In contrast, arginine-containing analogues were stable in MALDI-TOF, whereas peptides sharing a free N-terminal amino group were moderately subject to the same fragmentation. Effects of extraction delay time suggest that this process takes place very early (nanoseconds) at the beginning of the plume expansion. The effect of the nature of the matrix on the survival yield indicates a better correlation with the initial axial velocity than with the matrix proton affinity. All the data show some strong differences with the classical in-source decay (ISD). Our results suggest the role of the available protons in the close neighborhood of the peptide during the crystallization process and the prompt fragmentation induced by collisions in the first step of ablation. Undoubtedly, our study highlights that the MALDI-TOF analysis of peptides containing proline and no basic group should be carried out with extreme caution. © 2009 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Synthetic acidic proline-rich peptides devoid of basic chemical groups were studied by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF). Their ion mass spectra recorded in reflector positive ion mode have shown unusual features, i.e., absence or very weak presence of protonated peptide together with a major peak associated with fragmentation at a site that corresponds to the amide bond N-terminal to the first proline of the XPP motif. In contrast, arginine-containing analogues were stable in MALDI-TOF, whereas peptides sharing a free N-terminal amino group were moderately subject to the same fragmentation. Effects of extraction delay time suggest that this process takes place very early (nanoseconds) at the beginning of the plume expansion. The effect of the nature of the matrix on the survival yield indicates a better correlation with the initial axial velocity than with the matrix proton affinity. All the data show some strong differences with the classical in-source decay (ISD). Our results suggest the role of the available protons in the close neighborhood of the peptide during the crystallization process and the prompt fragmentation induced by collisions in the first step of ablation. Undoubtedly, our study highlights that the MALDI-TOF analysis of peptides containing proline and no basic group should be carried out with extreme caution. © 2009 American Chemical Society. |
Translocation and endocytosis for cell-penetrating peptide internalization Article de journal C -Y Jiao; D Delaroche; F Burlina; I D Alves; G Chassaing; S Sagan Journal of Biological Chemistry, 284 (49), p. 33957–33965, 2009. @article{Jiao:2009, title = {Translocation and endocytosis for cell-penetrating peptide internalization}, author = {C -Y Jiao and D Delaroche and F Burlina and I D Alves and G Chassaing and S Sagan}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-71749092534&doi=10.1074%2fjbc.M109.056309&partnerID=40&md5=ae55760943c381a72643b3e4ff85ef14}, doi = {10.1074/jbc.M109.056309}, year = {2009}, date = {2009-01-01}, journal = {Journal of Biological Chemistry}, volume = {284}, number = {49}, pages = {33957--33965}, abstract = {Cell-penetrating peptides (CPPs) share the property of cellular internalization. The question of how these peptides reach the cytoplasm of cells is still widely debated. Herein, we have used a mass spectrometry-based method that enables quantification of internalized and membrane-bound peptides. Internalization of the most used CPP was studied at 37 °C (endocytosis and translocation) and 4 °C (translocation) in wild type and proteoglycan-deficient Chinese hamster ovary cells. Both translocation and endocytosis are internalization pathways used by CPP. The choice of one pathway versus the other depends on the peptide sequence (not the number of positive changes), the extracellular peptide concentration, and the membrane components. There is no relationship between the high affinity of these peptides for the cell membrane and their internalization efficacy. Translocation occurs at low extracellular peptide concentration, whereas endocytosis, a saturable and cooperative phenomenon, is activated at higher concentrations. Translocation operates in a narrow time window, which implies a specific lipid/peptide co-import port in cells. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cell-penetrating peptides (CPPs) share the property of cellular internalization. The question of how these peptides reach the cytoplasm of cells is still widely debated. Herein, we have used a mass spectrometry-based method that enables quantification of internalized and membrane-bound peptides. Internalization of the most used CPP was studied at 37 °C (endocytosis and translocation) and 4 °C (translocation) in wild type and proteoglycan-deficient Chinese hamster ovary cells. Both translocation and endocytosis are internalization pathways used by CPP. The choice of one pathway versus the other depends on the peptide sequence (not the number of positive changes), the extracellular peptide concentration, and the membrane components. There is no relationship between the high affinity of these peptides for the cell membrane and their internalization efficacy. Translocation occurs at low extracellular peptide concentration, whereas endocytosis, a saturable and cooperative phenomenon, is activated at higher concentrations. Translocation operates in a narrow time window, which implies a specific lipid/peptide co-import port in cells. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc. |
Design, self-assembly, and molecular structures of 3D copper(II) capsules templated by BF4 - guest anions Article de journal C Desmarets; C Policar; L -M Chamoreau; H Amouri European Journal of Inorganic Chemistry, (29-30), p. 4396–4400, 2009. @article{Desmarets:2009, title = {Design, self-assembly, and molecular structures of 3D copper(II) capsules templated by BF4 - guest anions}, author = {C Desmarets and C Policar and L -M Chamoreau and H Amouri}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350150888&doi=10.1002%2fejic.200900606&partnerID=40&md5=a0e5525563850dda7c2083f3b040390c}, doi = {10.1002/ejic.200900606}, year = {2009}, date = {2009-01-01}, journal = {European Journal of Inorganic Chemistry}, number = {29-30}, pages = {4396--4400}, abstract = {The synthesis of two 3D M2L4 copper(II) capsules, [BF4C(CH3CN)2Cu2(L 1)4][BF4]3 (1) and ([BF 4C(BF4J2Cu2(L1) 4][BF4]) (2), by using l,3-(benzimidazol-l-ylmethyl)-2, 5dimethoxy-4,6-dimethylbenzene (L1) as a semirigid exobidentate ligand and [Cu(CH3CN)4][BF4]2 as a metallobrick is reported. Single-crystal X-ray diffraction studies show the encapsulation of a BF4 - anion in 1 and 2. Moreover, 2 dis-played three coordinated BF4 - anions, which is rare in supramolecular coordination host-guest chemistry. Remarkably, in both metallocages the weakly coordinated BF4 - anion acts as a template and interacts with the metal center through a weak Cu⋯F contact. © Wiley-VCH Verlag GmbH & Co. KGaA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The synthesis of two 3D M2L4 copper(II) capsules, [BF4C(CH3CN)2Cu2(L 1)4][BF4]3 (1) and ([BF 4C(BF4J2Cu2(L1) 4][BF4]) (2), by using l,3-(benzimidazol-l-ylmethyl)-2, 5dimethoxy-4,6-dimethylbenzene (L1) as a semirigid exobidentate ligand and [Cu(CH3CN)4][BF4]2 as a metallobrick is reported. Single-crystal X-ray diffraction studies show the encapsulation of a BF4 - anion in 1 and 2. Moreover, 2 dis-played three coordinated BF4 - anions, which is rare in supramolecular coordination host-guest chemistry. Remarkably, in both metallocages the weakly coordinated BF4 - anion acts as a template and interacts with the metal center through a weak Cu⋯F contact. © Wiley-VCH Verlag GmbH & Co. KGaA. |
G F Salgado; A Vogel; R Marquant; S E Feller; S Bouaziz; I D Alves Journal of Medicinal Chemistry, 52 (22), p. 7157–7162, 2009. @article{Salgado:2009, title = {The role of membranes in the organization of HIV-1 Gag p6 and Vpr: p6 Shows high affinity for membrane bilayers which substantially increases the interaction between p6 and Vpr}, author = {G F Salgado and A Vogel and R Marquant and S E Feller and S Bouaziz and I D Alves}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70949106813&doi=10.1021%2fjm901106t&partnerID=40&md5=65eec011b49d59c6511ba1d72eec434b}, doi = {10.1021/jm901106t}, year = {2009}, date = {2009-01-01}, journal = {Journal of Medicinal Chemistry}, volume = {52}, number = {22}, pages = {7157--7162}, abstract = {The molecular mechanism by which HIV-1 Gag proteins are targeted and transported to the plasma membrane after ribosomal synthesis is unknown. In this work, we investigated the potential interaction of p6 and Vpr with model membranes and have determined their binding constants. Plasmon waveguide resonance (PWR) experiments showed that p6 strongly interacts with membranes (Kd ∼40 nM), which may help explaining in part why Gag is targeted to and assembles into membranes by coating itself with lipids. Moreover, a substantial increased affinity of Vpr for p6 was observed while in a membrane environment. In order to further investigate the molecular properties behind the high affinity to model membranes, molecular dynamics simulations were carried out for p6 with a dodecylphosphocholine (DPC) micelle. The results indicate an integration route model for Vpr into virions and may help explain why previous reports failed to detect p6 in virion core preparations. ©2009 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The molecular mechanism by which HIV-1 Gag proteins are targeted and transported to the plasma membrane after ribosomal synthesis is unknown. In this work, we investigated the potential interaction of p6 and Vpr with model membranes and have determined their binding constants. Plasmon waveguide resonance (PWR) experiments showed that p6 strongly interacts with membranes (Kd ∼40 nM), which may help explaining in part why Gag is targeted to and assembles into membranes by coating itself with lipids. Moreover, a substantial increased affinity of Vpr for p6 was observed while in a membrane environment. In order to further investigate the molecular properties behind the high affinity to model membranes, molecular dynamics simulations were carried out for p6 with a dodecylphosphocholine (DPC) micelle. The results indicate an integration route model for Vpr into virions and may help explain why previous reports failed to detect p6 in virion core preparations. ©2009 American Chemical Society. |
Structural studies of HIV-1 Gag p6ct and Its interaction with Vpr determined by solution nuclear magnetic resonance Article de journal G F Salgado; R Marquant; A Vogel; I D Alves; S E Feller; N Morellet; S Bouaziz Biochemistry, 48 (11), p. 2355–2367, 2009. @article{Salgado:2009a, title = {Structural studies of HIV-1 Gag p6ct and Its interaction with Vpr determined by solution nuclear magnetic resonance}, author = {G F Salgado and R Marquant and A Vogel and I D Alves and S E Feller and N Morellet and S Bouaziz}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-64849112013&doi=10.1021%2fbi801794v&partnerID=40&md5=5565bc0935fcca763010b760dfd05488}, doi = {10.1021/bi801794v}, year = {2009}, date = {2009-01-01}, journal = {Biochemistry}, volume = {48}, number = {11}, pages = {2355--2367}, abstract = {The ability of human immunodeficiency virus type 1 (HIV-1) to egress from human cells by budding with the cell membrane remains a complex phenomenon of unclear steps. HIV-1 viral protein R (Vpr) incorporation in sorting virions relies greatly on the interaction with the group-specific antigen (Gag) C-terminal region, which encompasses protein p6. The complete role of p6 is still undetermined; however, it is thought that p6 interacts with protein core elements from the endosomal sorting complex ESCRT-1, known to sort ubiquitinated cargo into multivesicular bodies (MVB). The three-dimensional structure of the p6 C-terminus (p6ct) comprising amino acids 32-52, determined in this study using NMR methods, includes the region thought to interact with Vpr, i.e., the LXXLF sequence. Here we present new results indicating that the region which interacts with Vpr is the ELY 36 sequence, in the same region where mutational studies revealed that replacing Y36 with a phenylalanine would increase the infectivity of virions by 300-fold. The interaction of Vpr with an egg PC bilayer in the presence of p6ct measured by plasmon waveguide resonance (PWR) is ̃0.8 μM, ̃100 times stronger in the absence of p6ct. Our results suggests an interaction based on an ELYP 37 sequence bearing similarities with recently published results, which elegantly demonstrated that the HIV-1 Gag LYPx nLxxL motif interacts with Alix 3\'{o}4-702. Moreover, we performed a 60 ns molecular dynamics (MD) simulation of p6ct in DPC micelles. The MD results, supported by differential scanning calorimetry measurements in DMPC, show that p6ct adsorbs onto the DPC micelle surface by adopting a rather stable α-helix. Our results provide insights regarding the HIV-1 virion sorting mechanism, specifically concerning the interaction between p6 and Vpr. We also suggest that Gag p6 may adsorb onto the surface of membranes during the sorting process, a property so far only attributed to the N-terminal portion of Gag matrix (MA), which is myristylated. The implications of such a novel event provide an alternative direction toward understanding the assembly and escape mechanisms of virions, which have been undetected so far. © 2009 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The ability of human immunodeficiency virus type 1 (HIV-1) to egress from human cells by budding with the cell membrane remains a complex phenomenon of unclear steps. HIV-1 viral protein R (Vpr) incorporation in sorting virions relies greatly on the interaction with the group-specific antigen (Gag) C-terminal region, which encompasses protein p6. The complete role of p6 is still undetermined; however, it is thought that p6 interacts with protein core elements from the endosomal sorting complex ESCRT-1, known to sort ubiquitinated cargo into multivesicular bodies (MVB). The three-dimensional structure of the p6 C-terminus (p6ct) comprising amino acids 32-52, determined in this study using NMR methods, includes the region thought to interact with Vpr, i.e., the LXXLF sequence. Here we present new results indicating that the region which interacts with Vpr is the ELY 36 sequence, in the same region where mutational studies revealed that replacing Y36 with a phenylalanine would increase the infectivity of virions by 300-fold. The interaction of Vpr with an egg PC bilayer in the presence of p6ct measured by plasmon waveguide resonance (PWR) is ̃0.8 μM, ̃100 times stronger in the absence of p6ct. Our results suggests an interaction based on an ELYP 37 sequence bearing similarities with recently published results, which elegantly demonstrated that the HIV-1 Gag LYPx nLxxL motif interacts with Alix 3ó4-702. Moreover, we performed a 60 ns molecular dynamics (MD) simulation of p6ct in DPC micelles. The MD results, supported by differential scanning calorimetry measurements in DMPC, show that p6ct adsorbs onto the DPC micelle surface by adopting a rather stable α-helix. Our results provide insights regarding the HIV-1 virion sorting mechanism, specifically concerning the interaction between p6 and Vpr. We also suggest that Gag p6 may adsorb onto the surface of membranes during the sorting process, a property so far only attributed to the N-terminal portion of Gag matrix (MA), which is myristylated. The implications of such a novel event provide an alternative direction toward understanding the assembly and escape mechanisms of virions, which have been undetected so far. © 2009 American Chemical Society. |
C Luccardini; A V Yakovlev; M Pasche; S Gaillard; D Li; F Rousseau; R Ly; U Becherer; J -M Mallet; A Feltz; M Oheim Cell Calcium, 46 (3), p. 226, 2009. @article{Luccardini:2009, title = {Corrigendum to "Measuring mitochondrial and cytoplasmic Ca2+ in EGFP expressing cells with a low-affinity Calcium Ruby and its dextran conjugate" [Cell Calcium 45 (3) (2008)] (DOI:10.1016/j.ceca.2008.11.007)}, author = {C Luccardini and A V Yakovlev and M Pasche and S Gaillard and D Li and F Rousseau and R Ly and U Becherer and J -M Mallet and A Feltz and M Oheim}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-69249210939&doi=10.1016%2fj.ceca.2009.06.001&partnerID=40&md5=143097f5472f89ad18112a20ea7d6a29}, doi = {10.1016/j.ceca.2009.06.001}, year = {2009}, date = {2009-01-01}, journal = {Cell Calcium}, volume = {46}, number = {3}, pages = {226}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ab initio study of excitation energy transfer between quantum dots and dye molecules Article de journal H Tamura; J -M Mallet; M Oheim; I Burghardt Journal of Physical Chemistry C, 113 (18), p. 7548–7552, 2009. @article{Tamura:2009, title = {Ab initio study of excitation energy transfer between quantum dots and dye molecules}, author = {H Tamura and J -M Mallet and M Oheim and I Burghardt}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67049113893&doi=10.1021%2fjp811042t&partnerID=40&md5=ad82f74e914be46d0dd01274201f4335}, doi = {10.1021/jp811042t}, year = {2009}, date = {2009-01-01}, journal = {Journal of Physical Chemistry C}, volume = {113}, number = {18}, pages = {7548--7552}, abstract = {We investigate excitation energy transfer between a semiconductor nanocrystal (NC) and an organic dye molecule, using ab initio calculations. The electronic coupling is evaluated based on the full Coulombic interaction between the NC and dye transition densities. We explore the effect of the NC-dye relative configurations on the electronic coupling, using a (CdSe)6 cluster and a rhodamine cation as a simplified model system. Our analysis demonstrates the limitations of the commonly used F\"{o}rster theory for the NC-dye system and highlights the importance of considering the full Coulombic interactions of donor and acceptor. We find that energy transfer involves several electronic states and can occur even from optically dark states of the NC. The consequences for larger NC-dye systems are discussed. © 2009 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigate excitation energy transfer between a semiconductor nanocrystal (NC) and an organic dye molecule, using ab initio calculations. The electronic coupling is evaluated based on the full Coulombic interaction between the NC and dye transition densities. We explore the effect of the NC-dye relative configurations on the electronic coupling, using a (CdSe)6 cluster and a rhodamine cation as a simplified model system. Our analysis demonstrates the limitations of the commonly used Förster theory for the NC-dye system and highlights the importance of considering the full Coulombic interactions of donor and acceptor. We find that energy transfer involves several electronic states and can occur even from optically dark states of the NC. The consequences for larger NC-dye systems are discussed. © 2009 American Chemical Society. |
Measuring mitochondrial and cytoplasmic Ca2+ in EGFP expressing cells with a low-affinity Calcium Ruby and its dextran conjugate Article de journal C Luccardini; A V Yakovlev; M Pasche; S Gaillard; D Li; F Rousseau; R Ly; U Becherer; J -M Mallet; A Feltz; M Oheim Cell Calcium, 45 (3), p. 275–283, 2009. @article{Luccardini:2009a, title = {Measuring mitochondrial and cytoplasmic Ca2+ in EGFP expressing cells with a low-affinity Calcium Ruby and its dextran conjugate}, author = {C Luccardini and A V Yakovlev and M Pasche and S Gaillard and D Li and F Rousseau and R Ly and U Becherer and J -M Mallet and A Feltz and M Oheim}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-61649111725&doi=10.1016%2fj.ceca.2008.11.007&partnerID=40&md5=575fc8613aec2c8ecdd679859d3c5d1f}, doi = {10.1016/j.ceca.2008.11.007}, year = {2009}, date = {2009-01-01}, journal = {Cell Calcium}, volume = {45}, number = {3}, pages = {275--283}, abstract = {The limited choice and poor performance of red-emitting calcium (Ca2+) indicators have hampered microfluorometric measurements of the intracellular free Ca2+ concentration in cells expressing yellow- or green-fluorescent protein constructs. A long-wavelength Ca2+ indicator would also permit a better discrimination against cellular autofluorescence than the commonly used fluorescein-based probes. Here, we report an improved synthesis and characterization of Calcium Ruby, a red-emitting probe consisting of an extended rhodamine chromophore (578/602 nm peak excitation/emission) conjugated to BAPTA and having an additional NH2 linker arm. The low-affinity variant (KD,Ca ∼30 μM) with a chloride in meta position that was specifically designed for the detection of large and rapid Ca2+ transients. While Calcium Ruby is a mitochondrial Ca2+probe, its conjugation, via the NH2 tail, to a 10,000 MW dextran abolishes the sub-cellular compartmentalization and generates a cytosolic Ca2+ probe with an affinity matched to microdomain Ca2+ signals. As an example, we show depolarization-evoked Ca2+ signals triggering the exocytosis of individual chromaffin granules. Calcium Ruby should be of use in a wide range of applications involving dual- or triple labeling schemes or targeted sub-cellular Ca2+ measurements. © 2008 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The limited choice and poor performance of red-emitting calcium (Ca2+) indicators have hampered microfluorometric measurements of the intracellular free Ca2+ concentration in cells expressing yellow- or green-fluorescent protein constructs. A long-wavelength Ca2+ indicator would also permit a better discrimination against cellular autofluorescence than the commonly used fluorescein-based probes. Here, we report an improved synthesis and characterization of Calcium Ruby, a red-emitting probe consisting of an extended rhodamine chromophore (578/602 nm peak excitation/emission) conjugated to BAPTA and having an additional NH2 linker arm. The low-affinity variant (KD,Ca ∼30 μM) with a chloride in meta position that was specifically designed for the detection of large and rapid Ca2+ transients. While Calcium Ruby is a mitochondrial Ca2+probe, its conjugation, via the NH2 tail, to a 10,000 MW dextran abolishes the sub-cellular compartmentalization and generates a cytosolic Ca2+ probe with an affinity matched to microdomain Ca2+ signals. As an example, we show depolarization-evoked Ca2+ signals triggering the exocytosis of individual chromaffin granules. Calcium Ruby should be of use in a wide range of applications involving dual- or triple labeling schemes or targeted sub-cellular Ca2+ measurements. © 2008 Elsevier Ltd. All rights reserved. |
2008 |
Materials Doping through Sol–Gel Chemistry: A Little Something Can Make a Big Difference Article de journal J -M Nedelec; L Courtheoux; E Jallot; C Kinowski; J Lao; P Laquerriere; C Mansuy; G Renaudin; S Turrell Journal of Sol-Gel Science and Technology, 46 (3), p. 259-271, 2008. @article{Nedelec:2008, title = {Materials Doping through Sol\textendashGel Chemistry: A Little Something Can Make a Big Difference}, author = {J -M Nedelec and L Courtheoux and E Jallot and C Kinowski and J Lao and P Laquerriere and C Mansuy and G Renaudin and S Turrell}, doi = {10.1007/s10971-007-1665-0}, year = {2008}, date = {2008-04-01}, journal = {Journal of Sol-Gel Science and Technology}, volume = {46}, number = {3}, pages = {259-271}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
P V -E Khoury; J -F Colombel; S Joossens; A Standaert-Vitse; M Collot; J Halfvarson; A Ayadi; C J Landers; S Vermeire; P Rutgeerts; S R Targan; M Chamaillard; J -M Mallet; B Sendid; D Poulain American Journal of Gastroenterology, 103 (4), p. 949–957, 2008. @article{Khoury:2008, title = {Detection of antisynthetic mannoside antibodies (AΣMA) reveals heterogeneity in the ASCA response of Crohn's disease patients and contributes to differential diagnosis, stratification, and prediction}, author = {P V -E Khoury and J -F Colombel and S Joossens and A Standaert-Vitse and M Collot and J Halfvarson and A Ayadi and C J Landers and S Vermeire and P Rutgeerts and S R Targan and M Chamaillard and J -M Mallet and B Sendid and D Poulain}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-41849115954&doi=10.1111%2fj.1572-0241.2007.01648.x&partnerID=40&md5=4294c5c9fa3805786e5a085466eac527}, doi = {10.1111/j.1572-0241.2007.01648.x}, year = {2008}, date = {2008-01-01}, journal = {American Journal of Gastroenterology}, volume = {103}, number = {4}, pages = {949--957}, abstract = {OBJECTIVES: Anti-S. cerevisiae mannan antibodies (ASCA) are human antibodies associated with Crohn's disease (CD) reacting with Saccharomyces cerevisiae (S. cerevisiae) mannan polymer. As mannan is a complex and variable repertoire of oligomannoses acting as epitopes, we chemically synthesized (Σ) two major oligomannose epitopes, Man α-1,3 Man α-1,2 Man (ΣMan3) and Man α-1,3 Man α-1,2 Man α-1,2 Man (ΣMan4), and then explored how antisynthetic mannoside antibodies (AΣMA) compare with ASCA as markers of CD. METHODS: The study involved different cohorts of CD and ulcerative colitis (UC) patients and healthy controls who had been studied previously in several medical centers in Europe, the United States, and North Africa to determine the clinical value of ASCA in terms of differential diagnosis, evolution of indeterminate colitis (IC), and serotype-phenotype correlations. The comparison of AΣMA and ASCA included a total of 1,365 subjects: 772 CD, 261 UC, 43 IC, and 289 controls. RESULTS: The specificity of AΣMA was similar to that of ASCA (89% vs 93%), although the sensitivity was lower (38% vs 55%). Unexpectedly, 24% of the CD patients who were negative for ASCA and/or other CD-associated serologic markers were positive for AΣMA. AΣMA were associated with colonic involvement in CD (odds ratio [OR] 1.609, 95% confidence interval [CI] 1.033-2.506}, keywords = {}, pubstate = {published}, tppubtype = {article} } OBJECTIVES: Anti-S. cerevisiae mannan antibodies (ASCA) are human antibodies associated with Crohn's disease (CD) reacting with Saccharomyces cerevisiae (S. cerevisiae) mannan polymer. As mannan is a complex and variable repertoire of oligomannoses acting as epitopes, we chemically synthesized (Σ) two major oligomannose epitopes, Man α-1,3 Man α-1,2 Man (ΣMan3) and Man α-1,3 Man α-1,2 Man α-1,2 Man (ΣMan4), and then explored how antisynthetic mannoside antibodies (AΣMA) compare with ASCA as markers of CD. METHODS: The study involved different cohorts of CD and ulcerative colitis (UC) patients and healthy controls who had been studied previously in several medical centers in Europe, the United States, and North Africa to determine the clinical value of ASCA in terms of differential diagnosis, evolution of indeterminate colitis (IC), and serotype-phenotype correlations. The comparison of AΣMA and ASCA included a total of 1,365 subjects: 772 CD, 261 UC, 43 IC, and 289 controls. RESULTS: The specificity of AΣMA was similar to that of ASCA (89% vs 93%), although the sensitivity was lower (38% vs 55%). Unexpectedly, 24% of the CD patients who were negative for ASCA and/or other CD-associated serologic markers were positive for AΣMA. AΣMA were associated with colonic involvement in CD (odds ratio [OR] 1.609, 95% confidence interval [CI] 1.033-2.506 |
M Collot; B Sendid; A Fievez; C Savaux; A Standaert-Vitse; M Tabouret; A S Drucbert; P M Danzé; D Poulain; J -M Mallet Journal of Medicinal Chemistry, 51 (19), p. 6201–6210, 2008. @article{Collot:2008, title = {Biotin sulfone as a new tool for synthetic oligosaccharide immobilization: Application to multiple analysis profiling and surface plasmonic analysis of anti-Candida albicans antibody reactivity against α and β (1→2) oligomannosides}, author = {M Collot and B Sendid and A Fievez and C Savaux and A Standaert-Vitse and M Tabouret and A S Drucbert and P M Danz\'{e} and D Poulain and J -M Mallet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-53549134744&doi=10.1021%2fjm800099g&partnerID=40&md5=8fe7ec127f5de51b015a1e5e3beb840b}, doi = {10.1021/jm800099g}, year = {2008}, date = {2008-01-01}, journal = {Journal of Medicinal Chemistry}, volume = {51}, number = {19}, pages = {6201--6210}, abstract = {As a part of our glycoantigen synthetic program for diagnosis and basic analysis of yeast-related pathogenic mechanisms, a library of 1→2 oligomannosides suitable for immunoanalysis was prepared. The use of biotin sulfone, an oxidized form of biotin, offers a convenient solution for both oligosaccharide synthesis and immobilization on microspheres and surface plasmon resonance sensors. The application of this new strategy for the analysis of anti-Candida albicans antibody response through multiple-analyte profiling technology (Luminex) and with surface plasmonic analysis using biotin tagged synthetic oligosaccharides on avidin coated surfaces was validated using monoclonal antibodies. © 2008 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } As a part of our glycoantigen synthetic program for diagnosis and basic analysis of yeast-related pathogenic mechanisms, a library of 1→2 oligomannosides suitable for immunoanalysis was prepared. The use of biotin sulfone, an oxidized form of biotin, offers a convenient solution for both oligosaccharide synthesis and immobilization on microspheres and surface plasmon resonance sensors. The application of this new strategy for the analysis of anti-Candida albicans antibody response through multiple-analyte profiling technology (Luminex) and with surface plasmonic analysis using biotin tagged synthetic oligosaccharides on avidin coated surfaces was validated using monoclonal antibodies. © 2008 American Chemical Society. |
New thioglycoside derivatives for use in odourless synthesis of MUXF3 N-glycan fragments related to food allergens Article de journal M Collot; J Savreux; J -M Mallet Tetrahedron, 64 (7), p. 1523–1535, 2008. @article{Collot:2008a, title = {New thioglycoside derivatives for use in odourless synthesis of MUXF3 N-glycan fragments related to food allergens}, author = {M Collot and J Savreux and J -M Mallet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-37649008067&doi=10.1016%2fj.tet.2007.11.002&partnerID=40&md5=5ef009049ab903c60716881332ff9bee}, doi = {10.1016/j.tet.2007.11.002}, year = {2008}, date = {2008-01-01}, journal = {Tetrahedron}, volume = {64}, number = {7}, pages = {1523--1535}, abstract = {Thioglycosides are valuable tools for complex oligosaccharides' constructions. They present precious advantages due to their stability and crystalline nature. However, their major drawbacks are the repulsive smell of thiols utilised as precursors and, often, their toxicity such as in case of the commonly employed thiophenol and thioethanol. The use of commercially available methyl tert-butyl phenyl thiol (MbpSH) avoids these problems and is compatible with gram scale synthesis of thioglycoside donors. In this paper, we describe that Mbp thioglycosides are useful and convenient precursors for odourless oligosaccharide synthesis and we further demonstrate, as a proof of their versatility, their use in the construction of most of the glycosidic linkages found in N-glycans. © 2007 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Thioglycosides are valuable tools for complex oligosaccharides' constructions. They present precious advantages due to their stability and crystalline nature. However, their major drawbacks are the repulsive smell of thiols utilised as precursors and, often, their toxicity such as in case of the commonly employed thiophenol and thioethanol. The use of commercially available methyl tert-butyl phenyl thiol (MbpSH) avoids these problems and is compatible with gram scale synthesis of thioglycoside donors. In this paper, we describe that Mbp thioglycosides are useful and convenient precursors for odourless oligosaccharide synthesis and we further demonstrate, as a proof of their versatility, their use in the construction of most of the glycosidic linkages found in N-glycans. © 2007 Elsevier Ltd. All rights reserved. |
Synthetic sulfogalactosylceramide (sulfatide) and its use for the mass spectrometric quantitative urinary determination in metachromatic leukodystrophies Article de journal Y Cui; B Colsch; C Alonso; N Baumann; J -C Tabet; J -M Mallet; Y Zhang Glycoconjugate Journal, 25 (2), p. 147–155, 2008. @article{Cui:2008, title = {Synthetic sulfogalactosylceramide (sulfatide) and its use for the mass spectrometric quantitative urinary determination in metachromatic leukodystrophies}, author = {Y Cui and B Colsch and C Alonso and N Baumann and J -C Tabet and J -M Mallet and Y Zhang}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-39049149429&doi=10.1007%2fs10719-007-9067-7&partnerID=40&md5=f35d93ff6d2be81416a94170ff95d6a6}, doi = {10.1007/s10719-007-9067-7}, year = {2008}, date = {2008-01-01}, journal = {Glycoconjugate Journal}, volume = {25}, number = {2}, pages = {147--155}, abstract = {3-O-Sulfogalactosylceramides (sulfatides) accumulate in the genetic disease metachromatic leukodystrophy which is due to a defect in the catabolic enzyme, arylsulfatase A. Clinical diagnosis is usually confirmed by in vitro enzymatic deficiency of arylsulfatase A activity. The diagnosis may be complicated because of arylsulfatase A pseudo-deficiencies and another cause of MLD, sphingolipid activator B deficiency. As large quantities of sulfatides can be found in the urine in this disease, sulfatiduria appears as an extremely useful test. As recently enzyme replacement is underway, the quantitative determination, using an internal standard, appears particularly useful as a follow-up. Thus a non-physiological sulfatide was synthesized for this purpose, i.e. 3-O-sulfo-β-d-C17 galactosylceramide (3-O-Sulfo-d-Galactosyl- β1′→1-N-Heptadecanoyl-d-erythro-Sphingosine). It has been prepared through condensation of an azidosphingosine derivative with a protected d-galactopyranosyltrichloroacetimidate. Reduction of the azide was followed by acylation of a C-17 fatty acid. The key step was achieved by selective sulfation of the desired hydroxyl group on the sugar residue of the galactosylceramide using the stannylene methodology to give a 3′-sulfated beta-galactosyl C-17 ceramide. © 2007 Springer Science+Business Media, LLC.}, keywords = {}, pubstate = {published}, tppubtype = {article} } 3-O-Sulfogalactosylceramides (sulfatides) accumulate in the genetic disease metachromatic leukodystrophy which is due to a defect in the catabolic enzyme, arylsulfatase A. Clinical diagnosis is usually confirmed by in vitro enzymatic deficiency of arylsulfatase A activity. The diagnosis may be complicated because of arylsulfatase A pseudo-deficiencies and another cause of MLD, sphingolipid activator B deficiency. As large quantities of sulfatides can be found in the urine in this disease, sulfatiduria appears as an extremely useful test. As recently enzyme replacement is underway, the quantitative determination, using an internal standard, appears particularly useful as a follow-up. Thus a non-physiological sulfatide was synthesized for this purpose, i.e. 3-O-sulfo-β-d-C17 galactosylceramide (3-O-Sulfo-d-Galactosyl- β1′→1-N-Heptadecanoyl-d-erythro-Sphingosine). It has been prepared through condensation of an azidosphingosine derivative with a protected d-galactopyranosyltrichloroacetimidate. Reduction of the azide was followed by acylation of a C-17 fatty acid. The key step was achieved by selective sulfation of the desired hydroxyl group on the sugar residue of the galactosylceramide using the stannylene methodology to give a 3′-sulfated beta-galactosyl C-17 ceramide. © 2007 Springer Science+Business Media, LLC. |
Y Cui; B Colsch; C Afonso; N Baumann; J -C Tabet; J -M Mallet; Y Zhang Glycoconjugate Journal, 25 (2), p. 145, 2008. @article{Cui:2008a, title = {Synthetic sulfogalactosylceramide (sulfatide) and its use for the mass spectrometric quantitative urinary determination in metachromatic leukodystrophies (Glycoconjugate Journal DOI: 10.1007/s10719-007-9067-7)}, author = {Y Cui and B Colsch and C Afonso and N Baumann and J -C Tabet and J -M Mallet and Y Zhang}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-39049148424&doi=10.1007%2fs10719-007-9072-x&partnerID=40&md5=9f8557a960ae3a49662edfe49faf432f}, doi = {10.1007/s10719-007-9072-x}, year = {2008}, date = {2008-01-01}, journal = {Glycoconjugate Journal}, volume = {25}, number = {2}, pages = {145}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
2007 |
Concentration Effect on the Scintillation Properties of Sol–Gel Derived LuBO3 Doped with Eu3+ and Tb3+ Article de journal C Mansuy; J M Nedelec; C Dujardin; R Mahiou Optical Materials, 29 (6), p. 697-702, 2007. @article{Mansuy:2007, title = {Concentration Effect on the Scintillation Properties of Sol\textendashGel Derived LuBO3 Doped with Eu3+ and Tb3+}, author = {C Mansuy and J M Nedelec and C Dujardin and R Mahiou}, doi = {10.1016/j.optmat.2005.10.017}, year = {2007}, date = {2007-04-01}, journal = {Optical Materials}, volume = {29}, number = {6}, pages = {697-702}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Bis antennae amphiphilic cyclodextrins: the first examples Article de journal M Collot; M I Garcia-Moreno; C Fajolles; M Roux; L Mauclaire; J -M Mallet Tetrahedron Letters, 48 (48), p. 8566–8569, 2007. @article{Collot:2007, title = {Bis antennae amphiphilic cyclodextrins: the first examples}, author = {M Collot and M I Garcia-Moreno and C Fajolles and M Roux and L Mauclaire and J -M Mallet}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-35548995341&doi=10.1016%2fj.tetlet.2007.09.020&partnerID=40&md5=f8de7222a637eadc1c70bc14f4e98e1d}, doi = {10.1016/j.tetlet.2007.09.020}, year = {2007}, date = {2007-01-01}, journal = {Tetrahedron Letters}, volume = {48}, number = {48}, pages = {8566--8569}, abstract = {Methylated 6A,6D-diamino 6A,6D-dideoxy β-cyclodextrin 4 was coupled with three cholesterol substituted glutaric or succinic acids 5-7 to give amphiphilic cyclodextrins 1-3 with good yields. The succinic acid derivative 1, a typical member of this new family, has shown good compatibility with phosphatidyl choline monolayer and bilayer as confirmed by deuterium magnetic nuclear resonance (2H NMR). © 2007 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Methylated 6A,6D-diamino 6A,6D-dideoxy β-cyclodextrin 4 was coupled with three cholesterol substituted glutaric or succinic acids 5-7 to give amphiphilic cyclodextrins 1-3 with good yields. The succinic acid derivative 1, a typical member of this new family, has shown good compatibility with phosphatidyl choline monolayer and bilayer as confirmed by deuterium magnetic nuclear resonance (2H NMR). © 2007 Elsevier Ltd. All rights reserved. |
Getting across the plasma membrane and beyond: Intracellular uses of colloidal semiconductor nanocrystals Article de journal C Luccardini; A Yakovlev; S Gaillard; M Van 'T Hoff; A P Alberola; J -M Mallet; W J Parak; A Feltz; M Oheim Journal of Biomedicine and Biotechnology, 2007 , 2007. @article{Luccardini:2007, title = {Getting across the plasma membrane and beyond: Intracellular uses of colloidal semiconductor nanocrystals}, author = {C Luccardini and A Yakovlev and S Gaillard and M Van 'T Hoff and A P Alberola and J -M Mallet and W J Parak and A Feltz and M Oheim}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36949022046&doi=10.1155%2f2007%2f68963&partnerID=40&md5=06e26afc550ccd1aaa26858966dd1940}, doi = {10.1155/2007/68963}, year = {2007}, date = {2007-01-01}, journal = {Journal of Biomedicine and Biotechnology}, volume = {2007}, abstract = {Semiconductor nanocrystals (NCs) are increasingly being used as photoluminescen markers in biological imaging. Their brightness, large Stokes shift, and high photostability compared to organic fluorophores permit the exploration of biological phenomena at the single-molecule scale with superior temporal resolution and spatial precision. NCs have predominantly been used as extracellular markers for tagging and tracking membrane proteins. Successful internalization and intracellular labelling with NCs have been demonstrated for both fixed immunolabelled and live cells. However, the precise localization and subcellular compartment labelled are less clear. Generally, live cell studies are limited by the requirement of fairly invasive protocols for loading NCs and the relatively large size of NCs compared to the cellular machinery, along with the subsequent sequestration of NCs in endosomal/lysosomal compartments. For long-period observation the potential cytotoxicity of cytoplasmically loaded NCs must be evaluated. This review focuses on the challenges of intracellular uses of NCs. Copyright © 2007 Camilla Luccardini et al.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Semiconductor nanocrystals (NCs) are increasingly being used as photoluminescen markers in biological imaging. Their brightness, large Stokes shift, and high photostability compared to organic fluorophores permit the exploration of biological phenomena at the single-molecule scale with superior temporal resolution and spatial precision. NCs have predominantly been used as extracellular markers for tagging and tracking membrane proteins. Successful internalization and intracellular labelling with NCs have been demonstrated for both fixed immunolabelled and live cells. However, the precise localization and subcellular compartment labelled are less clear. Generally, live cell studies are limited by the requirement of fairly invasive protocols for loading NCs and the relatively large size of NCs compared to the cellular machinery, along with the subsequent sequestration of NCs in endosomal/lysosomal compartments. For long-period observation the potential cytotoxicity of cytoplasmically loaded NCs must be evaluated. This review focuses on the challenges of intracellular uses of NCs. Copyright © 2007 Camilla Luccardini et al. |
Weak calcium-mediated interactions between Lewis X-related trisaccharides studied by NMR measurements of residual dipolar couplings Article de journal G Nodet; L Poggi; D Abergel; C Gourmala; D Dong; Y Zhang; J -M Mallet; G Bodenhausen Journal of the American Chemical Society, 129 (29), p. 9080–9085, 2007. @article{Nodet:2007a, title = {Weak calcium-mediated interactions between Lewis X-related trisaccharides studied by NMR measurements of residual dipolar couplings}, author = {G Nodet and L Poggi and D Abergel and C Gourmala and D Dong and Y Zhang and J -M Mallet and G Bodenhausen}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547539474&doi=10.1021%2fja0711056&partnerID=40&md5=53aca08b440b69755694551b321f0625}, doi = {10.1021/ja0711056}, year = {2007}, date = {2007-01-01}, journal = {Journal of the American Chemical Society}, volume = {129}, number = {29}, pages = {9080--9085}, abstract = {The Lewis X (LeX) determinant, a trisaccharide with the carbohydrate sequence Galβ(1→4)-[Fucα(1→3)]GlcNAcβ, is believed to be responsible for Ca2+-mediated cell-cell interactions. In partly oriented phases composed of mixtures of penta(ethyleneglycol) monododecyl ether HO(CH2CH2O)5C 12H25 and n-hexanol in the presence of Ca2+ ions, the variation of the residual dipolar couplings 1DCH of various CiHi vectors in LeX as a function of the concentration of the trisaccharide demonstrates the existence of very weak LeX-Ca2+-LeX complexes in solution. Synthetic 3-, 4-, and 6-deoxy-LeX variants were also shown to form complexes in the presence of calcium ions, despite the replacement of one of their hydroxyl groups by hydrogen atoms. This is the first direct observation in solution of a calcium-mediated interaction between LeX molecules. © 2007 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Lewis X (LeX) determinant, a trisaccharide with the carbohydrate sequence Galβ(1→4)-[Fucα(1→3)]GlcNAcβ, is believed to be responsible for Ca2+-mediated cell-cell interactions. In partly oriented phases composed of mixtures of penta(ethyleneglycol) monododecyl ether HO(CH2CH2O)5C 12H25 and n-hexanol in the presence of Ca2+ ions, the variation of the residual dipolar couplings 1DCH of various CiHi vectors in LeX as a function of the concentration of the trisaccharide demonstrates the existence of very weak LeX-Ca2+-LeX complexes in solution. Synthetic 3-, 4-, and 6-deoxy-LeX variants were also shown to form complexes in the presence of calcium ions, despite the replacement of one of their hydroxyl groups by hydrogen atoms. This is the first direct observation in solution of a calcium-mediated interaction between LeX molecules. © 2007 American Chemical Society. |
Synthesis and characterization of polymer-coated quantum dots with integrated acceptor dyes as FRET-based nanoprobes Article de journal M T Fernández-Arguelles; A Yakovlev; R A Sperling; C Luccardini; S Gaillard; A S Medel; J -M Mallet; J -C Brochon; A Feltz; M Oheim; W J Parak Nano Letters, 7 (9), p. 2613–2617, 2007. @article{Fernandez-Arguelles:2007, title = {Synthesis and characterization of polymer-coated quantum dots with integrated acceptor dyes as FRET-based nanoprobes}, author = {M T Fern\'{a}ndez-Arguelles and A Yakovlev and R A Sperling and C Luccardini and S Gaillard and A S Medel and J -M Mallet and J -C Brochon and A Feltz and M Oheim and W J Parak}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948824503&doi=10.1021%2fnl070971d&partnerID=40&md5=88762ac5c5ceee29bcbc970273ad38f4}, doi = {10.1021/nl070971d}, year = {2007}, date = {2007-01-01}, journal = {Nano Letters}, volume = {7}, number = {9}, pages = {2613--2617}, abstract = {A fluorescence resonance energy transfer pair consisting of a colloidal quantum dot donor and multiple organic fluorophores as acceptors is reported and the photophysics of the system is characterized. Most nanoparticle-based biosensors reported so far use the detection of specific changes of the donor/acceptor distance under the influence of analyte binding. Our nanoparticle design on the other hand leads to sensors that detect spectral changes of the acceptor (under the influence of analyte binding) at fixed donor/acceptor distance by the introduction of the acceptor into the polymer coating. This approach allows for short acceptor-donor separation and thus for high-energy transfer efficiencies. Advantageously, the binding properties of the hydrophilic polymer coating further allows for addition of polyethylene glycol) shells for improved colloidal stability. © 2007 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A fluorescence resonance energy transfer pair consisting of a colloidal quantum dot donor and multiple organic fluorophores as acceptors is reported and the photophysics of the system is characterized. Most nanoparticle-based biosensors reported so far use the detection of specific changes of the donor/acceptor distance under the influence of analyte binding. Our nanoparticle design on the other hand leads to sensors that detect spectral changes of the acceptor (under the influence of analyte binding) at fixed donor/acceptor distance by the introduction of the acceptor into the polymer coating. This approach allows for short acceptor-donor separation and thus for high-energy transfer efficiencies. Advantageously, the binding properties of the hydrophilic polymer coating further allows for addition of polyethylene glycol) shells for improved colloidal stability. © 2007 American Chemical Society. |