Pascal PLAZA

Repair of the (6-4) photoproduct by DNA photolyase requires two photons Article de journal

J Yamamoto; P R Martin; S Iwai; P Plaza; K Brettel

Angewandte Chemie - International Edition, 52 (29), p. 7432–7436, 2013.

Ultrafast carbonyl motion of the photoactive yellow protein chromophore probed by femtosecond circular dichroism Article de journal

L Mendonça; F Hache; P Changenet-Barret; P Plaza; H Chosrowjan; S Taniguchi; Y Imamoto

Journal of the American Chemical Society, 135 (39), p. 14637–14643, 2013.

Photoantenna in two cryptochrome-photolyase proteins from O. tauri: Presence, nature and ultrafast photoinduced dynamics Article de journal

J Brazard; C Ley; F Lacombat; P Plaza; L Mony; M Heijde; G Zabulon; C Bowler

Journal of Photochemistry and Photobiology A: Chemistry, 234 , p. 135–145, 2012.

Photophysics and Photochemistry of Supramolecular Systems incollection

B Valeur; M -N Berberan-Santos; M M Martin; P Plaza

Analytical Methods in Supramolecular Chemistry, Volume 1 & 2: Second Edition, 1 , p. 287–336, 2012.

Reaction-coordinate tracking in the excited-state deactivation of the photoactive yellow protein chromophore in solution Article de journal

P Changenet-Barret; F Lacombat; P Plaza

Journal of Photochemistry and Photobiology A: Chemistry, 234 , p. 171–180, 2012.

New insights into the ultrafast photophysics of oxidized and reduced FAD in solution Article de journal

J Brazard; A Usman; F Lacombat; C Ley; M M Martin; P Plaza

Journal of Physical Chemistry A, 115 (15), p. 3251–3262, 2011.

The design, synthesis and photochemical study of a biomimetic cyclodextrin model of Photoactive Yellow Protein (PYP) Article de journal

C Loukou; P Changenet-Barret; M -N Rager; P Plaza; M M Martin; J -M Mallet

Organic and Biomolecular Chemistry, 9 (7), p. 2209–2218, 2011.

Characterization of two members of the cryptochrome/photolyase family from Ostreococcus tauri provides insights into the origin and evolution of cryptochromes Article de journal

M Heijde; G Zabulon; F Corellou; T Ishikawa; J Brazard; A Usman; F Sanchez; P Plaza; M Martin; A Falciatore; T Todo; F -Y Bouget; C Bowler

Plant, Cell and Environment, 33 (10), p. 1614–1626, 2010.

@article{Heijde:2010,
title = {Characterization of two members of the cryptochrome/photolyase family from Ostreococcus tauri provides insights into the origin and evolution of cryptochromes},
author = {M Heijde and G Zabulon and F Corellou and T Ishikawa and J Brazard and A Usman and F Sanchez and P Plaza and M Martin and A Falciatore and T Todo and F -Y Bouget and C Bowler},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956444369&doi=10.1111%2fj.1365-3040.2010.02168.x&partnerID=40&md5=ffb36def8c6c4cdcbe64f10945f50aee},
doi = {10.1111/j.1365-3040.2010.02168.x},
year = {2010},
date = {2010-01-01},
journal = {Plant, Cell and Environment},
volume = {33},
number = {10},
pages = {1614--1626},
abstract = {Cryptochromes (Crys) are blue light receptors believed to have evolved from the DNA photolyase protein family, implying that light control and light protection share a common ancient origin. In this paper, we report the identification of five genes of the Cry/photolyase family (CPF) in two green algae of the Ostreococcus genus. Phylogenetic analyses were used to confidently assign three of these sequences to cyclobutane pyrimidine dimer (CPD) photolyases, one of them to a DASH-type Cry, and a third CPF gene has high homology with the recently described diatom CPF1 that displays a bifunctional activity. Both purified OtCPF1 and OtCPF2 proteins show non-covalent binding to flavin adenine dinucleotide (FAD), and additionally to 5,10-methenyl-tetrahydrofolate (MTHF) for OtCPF2. Expression analyses revealed that all five CPF members of Ostreococcus tauri are regulated by light. Furthermore, we show that OtCPF1 and OtCPF2 display photolyase activity and that OtCPF1 is able to interact with the CLOCK:BMAL heterodimer, transcription factors regulating circadian clock function in other organisms. Finally, we provide evidence for the involvement of OtCPF1 in the maintenance of the Ostreococcus circadian clock. This work improves our understanding of the evolutionary transition between photolyases and Crys. © 2010 Blackwell Publishing Ltd.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

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Photoinduced cation translocation in a calix[4]biscrown: Towards a new type of light-driven molecular shuttle Article de journal

B Valeur; I Leray; L Zhao; V Souchon; R Métivier; P Plaza; C Ley; F Lacombat; M M Martin

ChemPhysChem, 11 (11), p. 2416–2423, 2010.

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}
}

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Spectro-temporal characterization of the photoactivation mechanism of two new oxidized cryptochrome/photolyase photoreceptors Article de journal

J Brazard; A Usman; F Lacombat; C Ley; M M Martin; P Plaza; L Mony; M Heijde; G Zabulon; C Bowler

Journal of the American Chemical Society, 132 (13), p. 4935–4945, 2010.

@article{Brazard:2010,
title = {Spectro-temporal characterization of the photoactivation mechanism of two new oxidized cryptochrome/photolyase photoreceptors},
author = {J Brazard and A Usman and F Lacombat and C Ley and M M Martin and P Plaza and L Mony and M Heijde and G Zabulon and C Bowler},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950802823&doi=10.1021%2fja1002372&partnerID=40&md5=27d44af43c214f4a5089bcf45cc5a3e4},
doi = {10.1021/ja1002372},
year = {2010},
date = {2010-01-01},
journal = {Journal of the American Chemical Society},
volume = {132},
number = {13},
pages = {4935--4945},
abstract = {The photoactivation dynamics of two new flavoproteins (OtCPF1 and OtCPF2) of the cryptochrome photolyase family (CPF), belonging to the green alga Ostreococcus tauri, was studied by broadband UV-vis femtosecond absorption spectroscopy. Upon excitation of the protein chromophoric cofactor, flavin adenine dinucleotide in its oxidized form (FADox), we observed in both cases the ultrafast photoreduction of FADox: in 390 fs for OtCPF1 and 590 fs for OtCPF2. Although such ultrafast electron transfer has already been reported for other flavoproteins and CPF members, the present result is the first demonstration with full spectral characterization of the mechanism. Analysis of the photoproduct spectra allowed identifying tryptophan as the primary electron donor. This residue is found to be oxidized to its protonated radical cation form (WH+), while FADox is reduced to FAD-. Subsequent kinetics were observed in the picosecond and subnanosecond regime, mostly described by a biexponential partial decay of the photoproduct transient signal (9 and 81 ps for OtCPF1, and 13 and 340 ps for OtCPF2), with reduced spectral changes, while a long-lived photoproduct remains in the nanosecond time scale. We interpret these observations within the model proposed by the groups of Brettel and Vos, which describes the photoreduction of FADH- within E. coli CPD photolyase (EcCPD) as a sequential electron transfer along a chain of three tryptophan residues, although in that case the rate limiting step was the primary photoreduction in 30 ps. In the present study, excitation of FADox permitted to reveal the following steps and spectroscopically assign them to the hole-hopping process along the tryptophan chain, accompanied by partial charge recombination at each step. In addition, structural analysis performed by homology modeling allowed us to propose a tentative structure of the relative orientations of FAD and the conserved tryptophan triad. The results of preliminary transient anisotropy measurements performed on OtCPF2 finally showed good compatibility with the oxidation of the distal tryptophan residue (WH351) in 340 ps, hence, with the overall Brettel-Vos mechanism. © 2010 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fermer

The photoactivation dynamics of two new flavoproteins (OtCPF1 and OtCPF2) of the cryptochrome photolyase family (CPF), belonging to the green alga Ostreococcus tauri, was studied by broadband UV-vis femtosecond absorption spectroscopy. Upon excitation of the protein chromophoric cofactor, flavin adenine dinucleotide in its oxidized form (FADox), we observed in both cases the ultrafast photoreduction of FADox: in 390 fs for OtCPF1 and 590 fs for OtCPF2. Although such ultrafast electron transfer has already been reported for other flavoproteins and CPF members, the present result is the first demonstration with full spectral characterization of the mechanism. Analysis of the photoproduct spectra allowed identifying tryptophan as the primary electron donor. This residue is found to be oxidized to its protonated radical cation form (WH+), while FADox is reduced to FAD-. Subsequent kinetics were observed in the picosecond and subnanosecond regime, mostly described by a biexponential partial decay of the photoproduct transient signal (9 and 81 ps for OtCPF1, and 13 and 340 ps for OtCPF2), with reduced spectral changes, while a long-lived photoproduct remains in the nanosecond time scale. We interpret these observations within the model proposed by the groups of Brettel and Vos, which describes the photoreduction of FADH- within E. coli CPD photolyase (EcCPD) as a sequential electron transfer along a chain of three tryptophan residues, although in that case the rate limiting step was the primary photoreduction in 30 ps. In the present study, excitation of FADox permitted to reveal the following steps and spectroscopically assign them to the hole-hopping process along the tryptophan chain, accompanied by partial charge recombination at each step. In addition, structural analysis performed by homology modeling allowed us to propose a tentative structure of the relative orientations of FAD and the conserved tryptophan triad. The results of preliminary transient anisotropy measurements performed on OtCPF2 finally showed good compatibility with the oxidation of the distal tryptophan residue (WH351) in 340 ps, hence, with the overall Brettel-Vos mechanism. © 2010 American Chemical Society.

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Ultrafast delocalization of cationic states in poly(N-vinylcarbazole) solid leading to carrier photogeneration Article de journal

T Katayama; Y Ishibashi; Y Morii; C Ley; J Brazard; F Lacombat; P Plaza; M M Martin; H Miyasaka

Physical Chemistry Chemical Physics, 12 (18), p. 4560–4563, 2010.

Femtosecond to subnanosecond multistep calcium photoejection from a crown ether-linked merocyanine Article de journal

C Ley; F Lacombat; P Plaza; M M Martin; I Leray; B Valeur

ChemPhysChem, 10 (1), p. 276–281, 2009.

Picosecond transient circular dichroism of the photoreceptor protein of the light-adapted form of Blepharisma japonicum Article de journal

F Hache; M -T Khuc; J Brazard; P Plaza; M M Martin; G Checcucci; F Lenci

Chemical Physics Letters, 483 (1-3), p. 133–137, 2009.

Spectroscopic characterization of a (6-4) photolyase from the green alga Ostreococcus tauri Article de journal

A Usman; J Brazard; M M Martin; P Plaza; M Heijde; G Zabulon; C Bowler

Journal of Photochemistry and Photobiology B: Biology, 96 (1), p. 38–48, 2009.

@article{Usman:2009,
title = {Spectroscopic characterization of a (6-4) photolyase from the green alga Ostreococcus tauri},
author = {A Usman and J Brazard and M M Martin and P Plaza and M Heijde and G Zabulon and C Bowler},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349227758&doi=10.1016%2fj.jphotobiol.2009.04.003&partnerID=40&md5=824d8a157edc5a374d7c96cfdf128d36},
doi = {10.1016/j.jphotobiol.2009.04.003},
year = {2009},
date = {2009-01-01},
journal = {Journal of Photochemistry and Photobiology B: Biology},
volume = {96},
number = {1},
pages = {38--48},
abstract = {The cofactor content of OtCPF1, a (6-4) photolyase isolated from the green marine alga Ostreococcus tauri, was characterized by steady-state absorption and fluorescence spectroscopy. The heterologously expressed, GST-fused, purified protein (MW: 89 kDa) is non-covalently bound to flavin adenine dinucleotide (FAD), with a flavin to apoprotein molecular ratio of 64%. No light-harvesting chromophore was found in this protein. In freshly purified OtCPF1, FAD is present in three different redox states: the fully oxidized form (FADox, 82%), the neutral semiquinone (FADHradical dot, 14%) and the fully reduced anion (FADH-, 4%). Keeping the sample in the dark, at 5 °C, yields oxidation of FADHradical dot and FADH-, partial release of FAD to the solution and slow degradation of the protein. Upon steady-state blue-light irradiation of OtCPF1 at 450 nm, photoreduction processes leading to an accumulation of stable FADHradical dot and FADH- species are observed. We demonstrate that this accumulation is due to the presence of an external electron donor agent in the purification buffer. Composition changes observed under steady-state photoexcitation are interpreted in terms of photoinduced reductions of FADox and FADHradical dot states and competitive back reactions. Specific irradiation by red light at 620 nm shows both photoreduction of FADHradical dot to FADH- and irreversible oxidation of FADHradical dot to FADox. The photoinduced oxidation reaction is believed to be indirectly caused by the external donor agent present in the buffer. Photoexcitation is also shown to stabilize the binding of FAD to the protein. We suggest this effect to be due to slight changes in the protein conformation, possibly strengthening the hydrogen-bonding network surrounding FAD. © 2009 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

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