2006
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Solvent effect on the excited-state dynamics of analogues of the photoactive Yellow Protein chromophore Article de journal A Espagne; P Changenet-Barret; P Plaza; M M Martin Journal of Physical Chemistry A, 110 (10), p. 3393–3404, 2006. @article{Espagne:2006a,
title = {Solvent effect on the excited-state dynamics of analogues of the photoactive Yellow Protein chromophore},
author = {A Espagne and P Changenet-Barret and P Plaza and M M Martin},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645500398&doi=10.1021%2fjp0563843&partnerID=40&md5=d174de26213df87496872cae2ddf21dd},
doi = {10.1021/jp0563843},
year = {2006},
date = {2006-01-01},
journal = {Journal of Physical Chemistry A},
volume = {110},
number = {10},
pages = {3393--3404},
abstract = {We previously reported that two analogues of the Photoactive Yellow Protein chromophore, trans-p-hydroxycinnamic acid (pCA2-) and its amide derivative (pCM-) in their deprotonated forms, undergo a transcis photoisomerization whereas the thioester derivative, trans-p-hydroxythiophenyl cinnamate (pCT-), does not. pCT- is also the only one to exhibit a short-lived intermediate on its excited-state deactivation pathway. We here further stress the existence of two different relaxation mechanisms for these molecules and examine the reaction coordinates involved. We looked at the effect of the solvent properties (viscosity, polarity, solvation dynamics) on their excited-state relaxation dynamics, probed by ultrafast transient absorption spectroscopy. Sensitivity to the solvent properties is found to be larger for pCT- than for pCA2- and pCM-. This difference is considered to reveal that either the relaxation pathway or the reaction coordinate is different for these two classes of analogues. It is also found to be correlated to the electron donor - acceptor character of the molecule. We attribute the excited-state deactivation of analogues bearing a weaker acceptor group, pCA2- and pCM-, to a stilbene-like photoisomerization mechanism with the concerted rotation of the ethylenic bond and one adjacent single bond. For pCT-, which contains a stronger acceptor group, we consider a photoisomerization mechanism mainly involving the single torsion of the ethylenic bond. The excited-state deactivation of pCT - would lead to the formation of a ground-state intermediate at the "perp" geometry, which would return to the initial trans conformation without net isomerization. © 2006 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We previously reported that two analogues of the Photoactive Yellow Protein chromophore, trans-p-hydroxycinnamic acid (pCA2-) and its amide derivative (pCM-) in their deprotonated forms, undergo a transcis photoisomerization whereas the thioester derivative, trans-p-hydroxythiophenyl cinnamate (pCT-), does not. pCT- is also the only one to exhibit a short-lived intermediate on its excited-state deactivation pathway. We here further stress the existence of two different relaxation mechanisms for these molecules and examine the reaction coordinates involved. We looked at the effect of the solvent properties (viscosity, polarity, solvation dynamics) on their excited-state relaxation dynamics, probed by ultrafast transient absorption spectroscopy. Sensitivity to the solvent properties is found to be larger for pCT- than for pCA2- and pCM-. This difference is considered to reveal that either the relaxation pathway or the reaction coordinate is different for these two classes of analogues. It is also found to be correlated to the electron donor - acceptor character of the molecule. We attribute the excited-state deactivation of analogues bearing a weaker acceptor group, pCA2- and pCM-, to a stilbene-like photoisomerization mechanism with the concerted rotation of the ethylenic bond and one adjacent single bond. For pCT-, which contains a stronger acceptor group, we consider a photoisomerization mechanism mainly involving the single torsion of the ethylenic bond. The excited-state deactivation of pCT - would lead to the formation of a ground-state intermediate at the "perp" geometry, which would return to the initial trans conformation without net isomerization. © 2006 American Chemical Society. |
Ultrafast photoisomerization of photoactive yellow protein chromophore analogues in solution: Influence of the protonation state Article de journal A Espagne; D H Paik; P Changenet-Barret; M M Martin; A H Zewail ChemPhysChem, 7 (8), p. 1717–1726, 2006. @article{Espagne:2006b,
title = {Ultrafast photoisomerization of photoactive yellow protein chromophore analogues in solution: Influence of the protonation state},
author = {A Espagne and D H Paik and P Changenet-Barret and M M Martin and A H Zewail},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748194569&doi=10.1002%2fcphc.200600137&partnerID=40&md5=1e4642cd9b9e7e944526096c65c4fc00},
doi = {10.1002/cphc.200600137},
year = {2006},
date = {2006-01-01},
journal = {ChemPhysChem},
volume = {7},
number = {8},
pages = {1717--1726},
abstract = {We investigate solvent viscosity and polarity effects on the photoisomerization of the protonated and deprotonated forms of two analogues of the photoactive yellow protein (PYP) chromophore. These are trans-p- hydroxybenzylidene acetone and trans-p-hydroxyphenyl cinnamate, studied in solutions of different polarity and viscosity at room temperature, by means of femtosecond fluorescence up-conversion. The fluorescence lifetimes of the protonated forms are found to be barely sensitive to solvent viscosity, and to increase with increasing solvent polarity. In contrast, the fluorescence decays of the deprotonated forms are significantly slowed down in viscous media and accelerated in polar solvents. These results elucidate the dramatic influence of the protonation state of the PYP chromophore analogues on their photoinduced dynamics. The viscosity and polarity effects are, respectively, interpreted in terms of different isomerization coordinates and charge redistribution in S 1. A trans-to-cis isomerization mechanism involving mainly the ethylenic double-bond torsion and/or salvation is proposed for the anionic forms, whereas "concerted" intramolecular motions are proposed for the neutral forms. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We investigate solvent viscosity and polarity effects on the photoisomerization of the protonated and deprotonated forms of two analogues of the photoactive yellow protein (PYP) chromophore. These are trans-p- hydroxybenzylidene acetone and trans-p-hydroxyphenyl cinnamate, studied in solutions of different polarity and viscosity at room temperature, by means of femtosecond fluorescence up-conversion. The fluorescence lifetimes of the protonated forms are found to be barely sensitive to solvent viscosity, and to increase with increasing solvent polarity. In contrast, the fluorescence decays of the deprotonated forms are significantly slowed down in viscous media and accelerated in polar solvents. These results elucidate the dramatic influence of the protonation state of the PYP chromophore analogues on their photoinduced dynamics. The viscosity and polarity effects are, respectively, interpreted in terms of different isomerization coordinates and charge redistribution in S 1. A trans-to-cis isomerization mechanism involving mainly the ethylenic double-bond torsion and/or salvation is proposed for the anionic forms, whereas "concerted" intramolecular motions are proposed for the neutral forms. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA. |
Vibrational Couplings and Ultrafast Relaxation of the O-Ħ Bending Mode in Liquid H2O Article de journal S Ashihara; N Huse; A Espagne; E T J Nibbering; T Elsaesser Chemical Physics Letters, 424 (1-3), p. 66-70, 2006, ISSN: 0009-2614. @article{RN54b,
title = {Vibrational Couplings and Ultrafast Relaxation of the O-{H} Bending Mode in Liquid H2O},
author = {S Ashihara and N Huse and A Espagne and E T J Nibbering and T Elsaesser},
doi = {10.1016/j.cplett.2006.04.051},
issn = {0009-2614},
year = {2006},
date = {2006-01-01},
journal = {Chemical Physics Letters},
volume = {424},
number = {1-3},
pages = {66-70},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
2005
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Biophysics: fluorescent biomolecules Book Chapter F Lenci; M M Martin; P Plaza; G Checcucci; N Angelini; A Sgarbossa Liedl, G L; Wyder, P (Ed.): Encyclopedia of Condensed Matter Physics, p. 222-235, Elsevier, 2005. @inbook{RN84,
title = {Biophysics: fluorescent biomolecules},
author = {F Lenci and M M Martin and P Plaza and G Checcucci and N Angelini and A Sgarbossa},
editor = {G L Liedl and P Wyder},
year = {2005},
date = {2005-01-01},
booktitle = {Encyclopedia of Condensed Matter Physics},
pages = {222-235},
publisher = {Elsevier},
keywords = {},
pubstate = {published},
tppubtype = {inbook}
}
|
Circular dichroism of the photoreceptor pigment oxyblepharismin Article de journal O Pieroni; P Plaza; M Mahet; N Angelini; G Checcucci; M Malatesta; M M Martin; F Lenci Photochemistry and Photobiology, 81 (6), p. 1343-1346, 2005, ISSN: 0031-8655. @article{RN47,
title = {Circular dichroism of the photoreceptor pigment oxyblepharismin},
author = {O Pieroni and P Plaza and M Mahet and N Angelini and G Checcucci and M Malatesta and M M Martin and F Lenci},
url = {<Go to ISI>://000233997300011},
doi = {10.1562/2005-04-28-rn-504},
issn = {0031-8655},
year = {2005},
date = {2005-01-01},
journal = {Photochemistry and Photobiology},
volume = {81},
number = {6},
pages = {1343-1346},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
Excitation energy effect on the early photophysics of hypericin in solution Article de journal P Plaza; M Mahet; O N Tchaikovskaya; M M Martin Chemical Physics Letters, 408 (1-3), p. 96–100, 2005. @article{Plaza:2005,
title = {Excitation energy effect on the early photophysics of hypericin in solution},
author = {P Plaza and M Mahet and O N Tchaikovskaya and M M Martin},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18844365175&doi=10.1016%2fj.cplett.2005.04.004&partnerID=40&md5=dd643226d928811afcb9d110a3e27342},
doi = {10.1016/j.cplett.2005.04.004},
year = {2005},
date = {2005-01-01},
journal = {Chemical Physics Letters},
volume = {408},
number = {1-3},
pages = {96--100},
abstract = {Picosecond transient absorption spectra of hypericin in solution have been recorded over the 350-850 nm spectral range under excitation fluences, respectively, 3/4 and four times the saturation fluence. At low fluence only a weak sub-100 ps decay component is detected, superimposed to the main nanosecond decay of the excited state. At high fluence a sub-10 ps rising component, comparable to that of earlier reports, is observed. This novel observation is discussed within the context of the state-of-the-art theory of hypericin photophysics, involving intramolecular excited-state H atom transfer. A cooling process in the S1 state after biphotonic absorption is proposed as an alternative explanation. © 2005 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Picosecond transient absorption spectra of hypericin in solution have been recorded over the 350-850 nm spectral range under excitation fluences, respectively, 3/4 and four times the saturation fluence. At low fluence only a weak sub-100 ps decay component is detected, superimposed to the main nanosecond decay of the excited state. At high fluence a sub-10 ps rising component, comparable to that of earlier reports, is observed. This novel observation is discussed within the context of the state-of-the-art theory of hypericin photophysics, involving intramolecular excited-state H atom transfer. A cooling process in the S1 state after biphotonic absorption is proposed as an alternative explanation. © 2005 Elsevier B.V. All rights reserved. |
Investigations of the primary events in a bacterial photoreceptor for photomotility: Photoactive yellow protein (PYP) Article de journal P Changenet-Barret; A Espagne; P Plaza; K J Hellingwerf; M M Martin New Journal of Chemistry, 29 (4), p. 527–534, 2005. @article{Changenet-Barret:2005,
title = {Investigations of the primary events in a bacterial photoreceptor for photomotility: Photoactive yellow protein (PYP)},
author = {P Changenet-Barret and A Espagne and P Plaza and K J Hellingwerf and M M Martin},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17444406349&doi=10.1039%2fb418134d&partnerID=40&md5=9d0e9b7ebb687d0a3c802932712fef79},
doi = {10.1039/b418134d},
year = {2005},
date = {2005-01-01},
journal = {New Journal of Chemistry},
volume = {29},
number = {4},
pages = {527--534},
abstract = {PYP, the Photoactive Yellow Protein, is a small water-soluble protein extracted from the cytosol of the halophilic purple bacterium Halorhodospira halophila. PYP is thought to mediate the phototactic response of the bacterium against blue light. Its chromophore is the deprotonated trans-p-hydroxycinnamic acid covalently linked, via a thioester bond, to the unique cysteine residue of the protein. Upon blue-light irradiation, PYP undergoes a photocycle. As for rhodopsins, the trans to cis isomerization of the chromophore was shown to be the first overall step of this photocycle. From time-resolved spectroscopy measurements on native PYP in solution, it emerged that the reaction involves a series of fast events on the subpicosecond and picosecond timescales, but the reaction path that leads to the formation of the cis isomer is not clear yet. A few years ago, we initiated a comparative study of native PYP and several chromophore analogues in solution in order to try to further clarify the early steps of the photocycle. Our experimental approach consists in probing, in real-time, the ultrafast photoinduced events by transient absorption and gain spectroscopy using the pump-probe technique. In the present paper, we review our experimental results and discuss them within the context of the recent literature. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
PYP, the Photoactive Yellow Protein, is a small water-soluble protein extracted from the cytosol of the halophilic purple bacterium Halorhodospira halophila. PYP is thought to mediate the phototactic response of the bacterium against blue light. Its chromophore is the deprotonated trans-p-hydroxycinnamic acid covalently linked, via a thioester bond, to the unique cysteine residue of the protein. Upon blue-light irradiation, PYP undergoes a photocycle. As for rhodopsins, the trans to cis isomerization of the chromophore was shown to be the first overall step of this photocycle. From time-resolved spectroscopy measurements on native PYP in solution, it emerged that the reaction involves a series of fast events on the subpicosecond and picosecond timescales, but the reaction path that leads to the formation of the cis isomer is not clear yet. A few years ago, we initiated a comparative study of native PYP and several chromophore analogues in solution in order to try to further clarify the early steps of the photocycle. Our experimental approach consists in probing, in real-time, the ultrafast photoinduced events by transient absorption and gain spectroscopy using the pump-probe technique. In the present paper, we review our experimental results and discuss them within the context of the recent literature. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005. |
Photophysical properties of pyrrolobenzenes with different linking and substitution pattern: The transition between charge transfer states with large (MICT) and small (TICT) resonance interaction Article de journal S Murali; P Changenet-Barret; C Ley; P Plaza; W Rettig; M M Martin; R Lapouyade Chemical Physics Letters, 411 (1-3), p. 192–197, 2005. @article{Murali:2005,
title = {Photophysical properties of pyrrolobenzenes with different linking and substitution pattern: The transition between charge transfer states with large (MICT) and small (TICT) resonance interaction},
author = {S Murali and P Changenet-Barret and C Ley and P Plaza and W Rettig and M M Martin and R Lapouyade},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-22544445595&doi=10.1016%2fj.cplett.2005.06.019&partnerID=40&md5=b178ce1b2f92f3efcf7aa5954951ac9e},
doi = {10.1016/j.cplett.2005.06.019},
year = {2005},
date = {2005-01-01},
journal = {Chemical Physics Letters},
volume = {411},
number = {1-3},
pages = {192--197},
abstract = {Pyrrolobenzenes, with different linking and substitution patterns, 2′-(4-cyanophenyl)-methylpyrrole (MP2-BN) and 2′-(2,5-cyanophenyl)- methylpyrrole (MP2-B25CN), are investigated by steady-state and time-resolved UV-Vis spectroscopy and compared to the parent compound N-pyrrolobenzonitrile (PBN). Both the electron donor-acceptor linking sites and the strength of the electron acceptor moiety are found to influence the emission characteristics of these compounds. The large radiative rate constant of MP2-BN indicates an allowed emission due to mesomeric interaction between the donor and acceptor moieties (MICT), whereas in the case of PBN and MP2-B25CN, the reduced radiative rate constant indicates a forbidden emission from a twisted intramolecular charge transfer (TICT) state. © 2005 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Pyrrolobenzenes, with different linking and substitution patterns, 2′-(4-cyanophenyl)-methylpyrrole (MP2-BN) and 2′-(2,5-cyanophenyl)- methylpyrrole (MP2-B25CN), are investigated by steady-state and time-resolved UV-Vis spectroscopy and compared to the parent compound N-pyrrolobenzonitrile (PBN). Both the electron donor-acceptor linking sites and the strength of the electron acceptor moiety are found to influence the emission characteristics of these compounds. The large radiative rate constant of MP2-BN indicates an allowed emission due to mesomeric interaction between the donor and acceptor moieties (MICT), whereas in the case of PBN and MP2-B25CN, the reduced radiative rate constant indicates a forbidden emission from a twisted intramolecular charge transfer (TICT) state. © 2005 Elsevier B.V. All rights reserved. |
Spectroscopic study of the chromophore–protein association and primary photoinduced events in the photoreceptor of Blepharisma japonicum Article de journal P Plaza; M Mahet; M M Martin; N Angelini; M Malatesta; G Checcucci; F Lenci Photochemical and Photobiological Sciences, 4 (9), p. 754–761, 2005. @article{Plaza:2005a,
title = {Spectroscopic study of the chromophore\textendashprotein association and primary photoinduced events in the photoreceptor of Blepharisma japonicum},
author = {P Plaza and M Mahet and M M Martin and N Angelini and M Malatesta and G Checcucci and F Lenci},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-25444441088&doi=10.1039%2fb417086e&partnerID=40&md5=dd3ced0e70c892fd5e0234b3abb6ea0f},
doi = {10.1039/b417086e},
year = {2005},
date = {2005-01-01},
journal = {Photochemical and Photobiological Sciences},
volume = {4},
number = {9},
pages = {754--761},
abstract = {Blepharisma japonicum is a ciliated protozoan exhibiting a strong step-up photophobic response upon illumination. The photoreceptor chromophores responsible for this response have been identified to be hypericin-like chromophores (blepharismin and oxyblepharismin), complexed to a 200 kDa non-water-soluble protein. The present work opens up new perspectives on the primary phototransduction steps of B. japonicum’s light perception through a joined approach by steady-state fluorescence spectroscopy, time-resolved fluorescence anisotropy and sub-picosecond transient absorption spectroscopy. The free chromophore of the light-adapted form of the cell (oxyblepharismin) was studied in various solvents and its spectroscopic properties, as well as its primary excited-state reactivity, compared with those of the corresponding pigment\textendashprotein complex, extracted by phosphate-concentration-step chromatography on a hydroxyapatite column. Fluorescence anisotropy together with SDS PAGE electrophoresis results confirm that oxyblepharismin is non-covalently bound to the apoprotein and show that, in the excited state, it is free to rotate in all directions within the binding site where it experiences a large local viscosity. Time-resolved anisotropy measurements on aromatic amino acids confirm that the molecular weight of the protein is of the order of 200 kDa. Although showing very similar steady-state spectra, free oxyblepharismin and its protein complex have noticeably different excited-state behaviours. In particular, the protein complex exhibits a pronounced short-lived absorption feature in the 640\textendash750 nm range, decaying biexponentially in 4 ps and 56 ps. Those decays, also observed in other spectral regions, are not found in the corresponding kinetics of the isolated pigment in solution. This early behaviour of the protein complex might be the signature of the primary phototransduction process, possibly involving an electron transfer from the pigment to a neighbouring protein acceptor residue as it had been suggested in previous studies. © 2005 The Royal Society of Chemistry and Owner Societies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Blepharisma japonicum is a ciliated protozoan exhibiting a strong step-up photophobic response upon illumination. The photoreceptor chromophores responsible for this response have been identified to be hypericin-like chromophores (blepharismin and oxyblepharismin), complexed to a 200 kDa non-water-soluble protein. The present work opens up new perspectives on the primary phototransduction steps of B. japonicum’s light perception through a joined approach by steady-state fluorescence spectroscopy, time-resolved fluorescence anisotropy and sub-picosecond transient absorption spectroscopy. The free chromophore of the light-adapted form of the cell (oxyblepharismin) was studied in various solvents and its spectroscopic properties, as well as its primary excited-state reactivity, compared with those of the corresponding pigment–protein complex, extracted by phosphate-concentration-step chromatography on a hydroxyapatite column. Fluorescence anisotropy together with SDS PAGE electrophoresis results confirm that oxyblepharismin is non-covalently bound to the apoprotein and show that, in the excited state, it is free to rotate in all directions within the binding site where it experiences a large local viscosity. Time-resolved anisotropy measurements on aromatic amino acids confirm that the molecular weight of the protein is of the order of 200 kDa. Although showing very similar steady-state spectra, free oxyblepharismin and its protein complex have noticeably different excited-state behaviours. In particular, the protein complex exhibits a pronounced short-lived absorption feature in the 640–750 nm range, decaying biexponentially in 4 ps and 56 ps. Those decays, also observed in other spectral regions, are not found in the corresponding kinetics of the isolated pigment in solution. This early behaviour of the protein complex might be the signature of the primary phototransduction process, possibly involving an electron transfer from the pigment to a neighbouring protein acceptor residue as it had been suggested in previous studies. © 2005 The Royal Society of Chemistry and Owner Societies. |
2004
|
Chemical structure effect on the excited-state relaxation dynamics of the PYP chromophore Inproceedings A Espagne; P Changenet-Barret; S Charier; J -B Baudin; L Jullien; P Plaza; M M Martin Martin, M M; Hynes, J T (Ed.): VIth International Conference on Femtochemistry, p. 421-424, Elsevier, 2004. @inproceedings{RN88,
title = {Chemical structure effect on the excited-state relaxation dynamics of the PYP chromophore},
author = {A Espagne and P Changenet-Barret and S Charier and J -B Baudin and L Jullien and P Plaza and M M Martin},
editor = {M M Martin and J T Hynes},
year = {2004},
date = {2004-01-01},
booktitle = {VIth International Conference on Femtochemistry},
pages = {421-424},
publisher = {Elsevier},
series = {Femtochemistry and Femtobiology: Ultrafast Events in Molecular Science},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Early molecular events in the photoactive yellow protein: Role of the chromophore photophysics Article de journal P Changenet-Barret; A Espagne; S Charier; J -B Baudin; L Jullien; P Plaza; K J Hellingwerf; M M Martin Photochemical and Photobiological Sciences, 3 (8), p. 823–829, 2004. @article{Changenet-Barret:2004,
title = {Early molecular events in the photoactive yellow protein: Role of the chromophore photophysics},
author = {P Changenet-Barret and A Espagne and S Charier and J -B Baudin and L Jullien and P Plaza and K J Hellingwerf and M M Martin},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-4644243446&doi=10.1039%2fb400398e&partnerID=40&md5=45520bcadbdf2612c16ef874b207d73b},
doi = {10.1039/b400398e},
year = {2004},
date = {2004-01-01},
journal = {Photochemical and Photobiological Sciences},
volume = {3},
number = {8},
pages = {823--829},
abstract = {We report a comparative study of the isomerization reaction in native and denatured photoactive yellow protein (PYP) and in various chromophore analogues in their trans deprotonated form. The excited-state relaxation dynamics was followed by subpicosecond transient absorption and gain spectroscopy. The free p-hydroxycinnamate (pCA2−) and its amide analogue (pCM-) are found to display a quite different transient spectroscopy from that of PYP. The excited-state deactivation leads to the formation of the ground-state cis isomer without any detectable intermediate with a mechanism comparable to trans-stilbene photoisomerization. On the contrary, the early stage of the excited-state deactivation of the free thiophenyl-p-hydroxycinnamate (pCT-) and of the denatured PYP is similar to that of the native protein. It involves the formation of an intermediate absorbing in the spectral region located between the bleaching and gain bands in less than 2 ps. However, in these two cases, the formation of the cis isomer has not been proved yet. This difference with pCA- and pCM- might result from the fact that, in the thioester substituted chromophore, simultaneous population of two quasi-degenerate excited states occurs upon excitation. This comparative study highlights the determining role of the chromophore structure and of its intrinsic properties in the primary molecular events in native PYP. © 2004 The Royal Society of Chemistry and Owner Societies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report a comparative study of the isomerization reaction in native and denatured photoactive yellow protein (PYP) and in various chromophore analogues in their trans deprotonated form. The excited-state relaxation dynamics was followed by subpicosecond transient absorption and gain spectroscopy. The free p-hydroxycinnamate (pCA2−) and its amide analogue (pCM-) are found to display a quite different transient spectroscopy from that of PYP. The excited-state deactivation leads to the formation of the ground-state cis isomer without any detectable intermediate with a mechanism comparable to trans-stilbene photoisomerization. On the contrary, the early stage of the excited-state deactivation of the free thiophenyl-p-hydroxycinnamate (pCT-) and of the denatured PYP is similar to that of the native protein. It involves the formation of an intermediate absorbing in the spectral region located between the bleaching and gain bands in less than 2 ps. However, in these two cases, the formation of the cis isomer has not been proved yet. This difference with pCA- and pCM- might result from the fact that, in the thioester substituted chromophore, simultaneous population of two quasi-degenerate excited states occurs upon excitation. This comparative study highlights the determining role of the chromophore structure and of its intrinsic properties in the primary molecular events in native PYP. © 2004 The Royal Society of Chemistry and Owner Societies. |
Fast excited-state reaction in the photoreceptor pigment-protein complex of the ciliate Blepharisma japonicum Inproceedings M Mahet; P Plaza; M M Martin; G Checcucci; F Lenci Martin, M M; Hynes, J T (Ed.): VIth International Conference on Femtochemistry, p. 441-444, Elsevier, 2004. @inproceedings{RN89,
title = {Fast excited-state reaction in the photoreceptor pigment-protein complex of the ciliate Blepharisma japonicum},
author = {M Mahet and P Plaza and M M Martin and G Checcucci and F Lenci},
editor = {M M Martin and J T Hynes},
year = {2004},
date = {2004-01-01},
booktitle = {VIth International Conference on Femtochemistry},
pages = {441-444},
publisher = {Elsevier},
series = {Femtochemistry and Femtobiology: Ultrafast Events in Molecular Science},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Isomerization process in the native and denatured Photoactive Yellow Protein probed by subpicosecond absorption spectroscopy Inproceedings P Changenet-Barret; A Espagne; P Plaza; M M Martin; Y J Hellingwerf Martin, M M; Hynes, J T (Ed.): VIth International Conference on Femtochemistry, p. 417-420, Elsevier, 2004. @inproceedings{RN87,
title = {Isomerization process in the native and denatured Photoactive Yellow Protein probed by subpicosecond absorption spectroscopy},
author = {P Changenet-Barret and A Espagne and P Plaza and M M Martin and Y J Hellingwerf},
editor = {M M Martin and J T Hynes},
year = {2004},
date = {2004-01-01},
booktitle = {VIth International Conference on Femtochemistry},
pages = {417-420},
publisher = {Elsevier},
series = {Femtochemistry and Femtobiology: Ultrafast Events in Molecular Science},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Ultrafast photoinduced charge transfer in fluorinated derivatives of DMABN Inproceedings S Murali; P Changenet-Barret; C Ley; P Plaza; W Rettig; M M Martin; A I Tolmachev Martin, M M; Hynes, J T (Ed.): VIth International Conference on Femtochemistry, p. 323-326, Elsevier, 2004. @inproceedings{RN86,
title = {Ultrafast photoinduced charge transfer in fluorinated derivatives of DMABN},
author = {S Murali and P Changenet-Barret and C Ley and P Plaza and W Rettig and M M Martin and A I Tolmachev},
editor = {M M Martin and J T Hynes},
year = {2004},
date = {2004-01-01},
booktitle = {VIth International Conference on Femtochemistry},
pages = {323-326},
publisher = {Elsevier},
series = {Femtochemistry and Femtobiology: Ultrafast Events in Molecular Science},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
2003
|
Calcium photorelease from a symmetrical donor-acceptor-donor bis-crown-fluoroionophore evidenced by ultrafast absorption spectroscopy Article de journal N Marcotte; P Plaza; D Lavabre; S Fery-Forgues; M M Martin The Journal of Physical Chemistry A, 107 (14), p. 2394-2402, 2003, ISSN: 1089-5639. @article{RN43,
title = {Calcium photorelease from a symmetrical donor-acceptor-donor bis-crown-fluoroionophore evidenced by ultrafast absorption spectroscopy},
author = {N Marcotte and P Plaza and D Lavabre and S Fery-Forgues and M M Martin},
url = {<Go to ISI>://000182042400002},
doi = {10.1021/jp027495u},
issn = {1089-5639},
year = {2003},
date = {2003-01-01},
journal = {The Journal of Physical Chemistry A},
volume = {107},
number = {14},
pages = {2394-2402},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|