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Accueil > Départements > Biochimie, Biophysique et Biologie Structurale > Winfried LEIBL : Photocatalyse et Biohydrogène

Publications de l’équipe


  • P. Gotico, B. Boitrel, R. Guillot, M. Sircoglou, A. Quaranta, Z. Halime, W. Leibl, et A. Aukauloo, « Second-Sphere Biomimetic Multipoint Hydrogen-Bonding Patterns to Boost CO2 Reduction of Iron Porphyrins », Angewandte Chemie (International Ed. in English), vol. 58, nᵒ 14, p. 4504-4509, mars 2019.
    Résumé : Inspired by nature's orchestra of chemical subtleties to activate and reduce CO2 , we have developed a family of iron porphyrin derivatives in to which we have introduced urea groups functioning as multipoint hydrogen-bonding pillars on the periphery of the porphyrinic ring. This structure closely resembles the hydrogen-bond stabilization scheme of the carbon dioxide (CO2 ) adduct in the carbon monoxide dehydrogenase (CODH). We found that such changes to the second coordination sphere significantly lowered the overpotential for CO2 reduction in this family of molecular catalysts and importantly increased the CO2 binding rate while maintaining high turnover frequency (TOF) and selectivity. Entrapped water molecules within the molecular clefts were found to be the source of protons for the CO2 reduction.
    Mots-clés : B3S, binding, carbon dioxide reduction, carbon-dioxide, co2-to-co electrochemical conversion, complexes, efficient, fe, hydrogen bonding, iron, LPB, models, molecular catalysis, picket-fence porphyrins, porphyrins, urea.

  • F. Lacombat, A. Espagne, N. Dozova, P. Plaza, P. Müller, K. Brettel, S. Franz-Badur, et L. - O. Essen, « Ultrafast Oxidation of a Tyrosine by Proton-Coupled Electron Transfer Promotes Light Activation of an Animal-like Cryptochrome », Journal of the American Chemical Society, vol. 141, nᵒ 34, p. 13394-13409, août 2019.
    Résumé : The animal-like cryptochrome of Chlamydomonas reinhardtii (CraCRY) is a recently discovered photoreceptor that controls the transcriptional profile and sexual life cycle of this alga by both blue and red light. CraCRY has the uncommon feature of efficient formation and longevity of the semireduced neutral form of its FAD cofactor upon blue light illumination. Tyrosine Y373 plays a crucial role by elongating , as fourth member, the electron transfer (ET) chain found in most other cryptochromes and DNA photolyases, which comprises a conserved tryptophan triad. Here, we report the full mechanism of light-induced FADH• formation in CraCRY using transient absorption spectroscopy from hundreds of femtoseconds to seconds. Electron transfer starts from ultrafast reduction of excited FAD to FAD•- by the proximal tryptophan (0.4 ps) and is followed by delocalized migration of the produced WH•+ radical along the tryptophan triad (∼4 and ∼50 ps). Oxidation of Y373 by coupled ET to WH•+ and deprotonation then proceeds in ∼800 ps, without any significant kinetic isotope effect, nor a pH effect between pH 6.5 and 9.0. The FAD•-/Y373• pair is formed with high quantum yield (∼60%); its intrinsic decay by recombination is slow (∼50 ms), favoring reduction of Y373• by extrinsic agents and protonation of FAD•- to form the long-lived, red-light absorbing FADH• species. Possible mechanisms of tyrosine oxidation by ultrafast proton-coupled ET in CraCRY, a process about 40 times faster than the archetypal tyrosine-Z oxidation in photosystem II, are discussed in detail.
    Mots-clés : B3S, LPB.

  • G. Sipka, P. Müller, K. Brettel, M. Magyar, L. Kovács, Q. Zhu, Y. Xiao, G. Han, P. H. Lambrev, J. - R. Shen, et G. Ő. Ő. Garab, « Redox transients of P680 associated with the incremental chlorophyll-a fluorescence yield rises elicited by a series of saturating flashes in diuron-treated Photosystem II core complex of Thermosynechococcus vulcanus », Physiologia Plantarum, vol. 166, nᵒ 1, p. 22-32, févr. 2019.
    Résumé : Recent chlorophyll-a fluorescence yield measurements, using single-turnover saturating flashes (STSFs), have revealed the involvement of a rate-limiting step in the reactions following the charge separation induced by the first flash (Magyar et al. 2018). As also shown here, in diuron-inhibited PSII core complexes isolated from Thermosynechococcus vulcanus the fluorescence maximum could only be reached by a train of STSFs. In order to elucidate the origin of the fluorescence yield increments in STSF series, we performed transient absorption measurements at 819 nm, reflecting the photooxidation and re-reduction kinetics of the primary electron donor P680. Upon single flash excitation of the dark-adapted sample, the decay kinetics could be described with lifetimes of 17 ns (~50%) and 167 ns (~30%), and a longer-lived component (~20%). This kinetics are attributed to re-reduction of P680•+ by the donor side of PSII. In contrast, upon second-flash (with Δt between 5 μs and 100 ms) or repetitive excitation, the 819 nm absorption changes decayed with lifetimes of about 2 ns (~60%) and 10 ns (~30%), attributed to recombination of the primary radical pair P680•+ Pheo•- , and a small longer-lived component (~10%). These data confirm that only the first STSF is capable of generating stable charge separation - leading to the reduction of QA ; and thus, the fluorescence yield increments elicited by the consecutive flashes must have a different physical origin. Our double-flash experiments indicate that the rate-limiting steps, detected by chlorophyll-a fluorescence, are not correlated with the turnover of P680. This article is protected by copyright. All rights reserved.
    Mots-clés : absorbency changes, absorption-spectroscopy, B3S, excitation, LPB, p-680, particles, pheophytin, primary electron-donor, primary-charge separation, recombination pathways, reduction kinetics.

  • N. T. Vo, Y. Mekmouche, T. Tron, R. Guillot, F. Banse, Z. Halime, M. Sircoglou, W. Leibl, et A. Aukauloo, « A Reversible Electron Relay to Exclude Sacrificial Electron Donors in the Photocatalytic Oxygen Atom Transfer Reaction with O2 in Water », Angewandte Chemie (International Ed. in English), sept. 2019.
    Résumé : Using light energy and O2 for the direct chemical oxidation of organic substrates is a major challenge. A limitation is the use of sacrificial electron donors to activate O2 by reductive quenching of the photosensitizer, generating undesirable side products. A reversible electron acceptor, methyl viologen, can act as electron shuttle to oxidatively quench the photosensitizer, [Ru(bpy)3 ]2+ , generating the highly oxidized chromophore and the powerful reductant methyl-viologen radical MV+. . MV+. can then reduce an iron(III) catalyst to the iron(II) form and concomitantly O2 to O2.- in an aqueous medium to generate an active iron(III)-(hydro)peroxo species. The oxidized photosensitizer is reset to its ground state by oxidizing an alkene substrate to an alkenyl radical cation. Closing the loop, the reaction of the iron reactive intermediate with the substrate or its radical cation leads to the formation of two oxygenated compounds, the diol and the aldehyde following two different pathways.
    Mots-clés : B3S, electron relay, iron complexes, LPB, oxygen atom transfer, photocatalysis, time-resolved spectroscopy.


  • M. Byrdin, C. Duan, D. Bourgeois, et K. Brettel, « A Long-Lived Triplet State Is the Entrance Gateway to Oxidative Photochemistry in Green Fluorescent Proteins », Journal of the American Chemical Society, vol. 140, nᵒ 8, p. 2897-2905, févr. 2018.
    Résumé : Though ubiquitously used as selective fluorescence markers in cellular biology, fluorescent proteins (FPs) still have not disclosed all of their surprising properties. One important issue, notably for single-molecule applications, is the nature of the triplet state, suggested to be the starting point for many possible photochemical reactions leading to phenomena such as blinking or bleaching. Here, we applied transient absorption spectroscopy to characterize dark states in the prototypical enhanced green fluorescent protein (EGFP) of hydrozoan origin and, for comparison, in IrisFP, a representative phototransformable FP of anthozoan origin. We identified a long-lived (approximately 5 ms) dark state that is formed with a quantum yield of approximately 1% and has pronounced absorption throughout the visible-NIR range (peak at around 900 nm). Detection of phosphorescence emission with identical kinetics and excitation spectrum allowed unambiguous identification of this state as the first excited triplet state of the deprotonated chromophore. This triplet state was further characterized by determining its phosphorescence emission spectrum, the temperature dependence of its decay kinetics and its reactivity toward oxygen and electron acceptors and donors. It is suggested that it is this triplet state that lies at the origin of oxidative photochemistry in green FPs, leading to phenomena such as so-called "oxidative redding", "primed photoconversion", or, in a manner similar to that previously observed for organic dyes, redox induced blinking control with the reducing and oxidizing system ("ROXS").
    Mots-clés : B3S, LPB.

  • G. Chararalambidis, S. Das, A. Trapali, A. Quaranta, M. Orio, Z. Halime, P. Fertey, R. Guillot, A. Coutsolelos, W. Leibl, A. Aukauloo, et M. Sircoglou, « Water Molecules Gating a Photoinduced One Electron Two Protons Transfer in a Tyr/His model of Photosystem II », Angewandte Chemie (International Ed. in English), mai 2018.
    Résumé : In this report, we investigate on a biomimetic model of a H-bonded TyrZ/His190 pair covalently attached to a porphyrin sensitizer. Laser flash photolysis in presence of an external electron acceptor reveals the need of water molecules to unlock the light-induced oxidation of the phenol through an intramolecular pathway. Kinetics monitoring encompasses two fast phases with distinct spectral properties. The first phase is related to one-electron transfer from the phenol to the porphyrin radical cation coupled with a domino two-proton transfer leading to the ejection of a proton from the imidazole-phenol pair. The second phase concerns the convoy of the released proton to the porphyrin N4 coordinating cavity. Importantly, our study provides an unprecedented example of light induced electron transfer process in a TyrZ/His190 model of Photosystem II, evidencing the movement of both the phenol and imidazole protons along an isoenergetic pathway.
    Mots-clés : artificial photosynthesis, B3S, LPB, Proton Coupled Electron Transfer, TyrZ-His190 model.

  • P. Gotico, A. Del Vecchio, D. Audisio, A. Quaranta, Z. Halime, W. Leibl, et A. Aukauloo, « Visible-Light-Driven Reduction of CO2 to CO and Its Subsequent Valorization in Carbonylation Chemistry and C-13 Isotope Labeling », Chemphotochem, vol. 2, nᵒ 8, p. 715-719, août 2018.
    Résumé : A convenient and safe approach in valorizing carbon monoxide (CO) produced from the photocatalytic reduction of carbon dioxide (CO2) has been investigated. Visible light was used to drive an optimized photocatalytic reduction using a ruthenium trisbipyridine complex as a sensitizer and a rhenium bipyridyl carbonyl complex as a catalyst to perform an efficient reduction of CO2 to CO, which was then simultaneously utilized in a palladium-catalyzed aminocarbonylation reaction at room temperature. This approach provides safe handling of the produced CO which also opens the way for a more efficient application of C-13-isotope and C-14-radioisotope-labeled CO2 in pharmaceutically relevant drug labeling.
    Mots-clés : artificial photosynthesis, B3S, carbon dioxide, carbon-dioxide, carbonylation, continuous-flow, formic-acid, highly efficient, homogeneous catalysts, isotopic labeling, LPB, metal-complexes, photocatalysis, photocatalytic reduction, photochemical reduction, photoredox catalysis, rhenium(i) complex.

  • M. - H. Ha-Thi, V. - T. Pham, T. Pino, V. Maslova, A. Quaranta, C. Lefumeux, W. Leibl, et A. Aukauloo, « Photoinduced electron transfer in a molecular dyad by nanosecond pump-pump-probe spectroscopy », Photochemical & Photobiological Sciences, vol. 17, nᵒ 7, p. 903-909, juill. 2018.
    Résumé : The design of robust and inexpensive molecular photocatalysts for the conversion of abundant stable molecules like H2O and CO2 into an energetic carrier is one of the major fundamental questions for scientists nowadays. The outstanding challenge is to couple single photoinduced charge separation events with the sequential accumulation of redox equivalents at the catalytic unit for performing multielectronic catalytic reactions. Herein, double excitation by nanosecond pump-pump-probe experiments was used to interrogate the photoinduced charge transfer and charge accumulation on a molecular dyad composed of a porphyrin chromophore and a ruthenium-based catalyst in the presence of a reversible electron acceptor. An accumulative charge transfer state is unattainable because of rapid reverse electron transfer to the photosensitizer upon the second excitation and the low driving force of the forward photodriven electron transfer reaction. Such a method allows the fundamental understanding of the relaxation mechanism after two sequential photon absorptions, deciphering the undesired electron transfer reactions that limit the charge accumulation efficiency. This study is a step toward the improvement of synthetic strategies of molecular photocatalysts for light-induced charge accumulation and more generally, for solar energy conversion.
    Mots-clés : accumulative charge separation, artificial photosynthesis, B3S, catalytic water oxidation, co2, complex, LPB, photocatalysts, photosensitizer, photosystem-ii, reduction, solar-energy.

  • A. Khadhraoui, P. Gotico, B. Boitrel, W. Leibl, Z. Halime, et A. Aukauloo, « Local ionic liquid environment at a modified iron porphyrin catalyst enhances the electrocatalytic performance of CO2 to CO reduction in water », Chemical Communications, vol. 54, nᵒ 82, p. 11630-11633, oct. 2018.
    Résumé : In this study we report a strategy to attach methylimidazolium fragments as ionic liquid units on an established iron porphyrin catalyst for the selective reduction of CO2 to CO. Importantly, we found that the tetra-methylimidazolium containing porphyrin exhibits an exalted electrocatalytic activity at low overpotential in water precluding the need for an external proton donor.
    Mots-clés : B3S, benchmarking, carbon-dioxide, co2-to-co electrochemical conversion, complex, driven, efficient, electroreduction, fe, LMB, LPB, molecular catalysts, systems.

  • P. Müller, E. Ignatz, S. Kiontke, K. Brettel, et L. - O. Essen, « Sub-nanosecond tryptophan radical deprotonation mediated by a protein-bound water cluster in class II DNA photolyases », Chemical Science, vol. 9, nᵒ 5, p. 1200-1212, 2018.

  • T. - T. Tran, M. - H. Ha-Thi, T. Pino, A. Quaranta, C. Lefumeux, W. Leibl, et A. Aukauloo, « Snapshots of Light Induced Accumulation of Two Charges on Methylviologen using a Sequential Nanosecond Pump–Pump Photoexcitation », The Journal of Physical Chemistry Letters, vol. 9, nᵒ 5, p. 1086-1091, 2018.


  • K. Brettel, M. Byrdin, et M. H. Vos, « Ultrafast Light-Induced Processes in DNA Photolyase and Its Substrate-Bound Complex », in Ultrafast Dynamics at the Nanoscale: Biomolecules and Supramolecular Assemblies, I. Burghardt et S. Haacke, Éd. Penthouse Level, Suntec Tower 3, 8 Temasek Boulevard, Singapore 038988: Pan Stanford Publishing, 2017, p. 65-90.

  • Ultrafast Dynamics at the Nanoscale: Biomolecules and Supramolecular Assemblies. Penthouse Level, Suntec Tower 3, 8 Temasek Boulevard, Singapore 038988: Pan Stanford Publishing, 2017.

  • R. Farran, C. Ducloiset, J. Buendia, N. T. Vo, R. Guillot, Z. Halime, P. Dauban, W. Leibl, M. Sircoglou, et A. Aukauloo, « Light-Induced Activation of the Du Bois [Rh <sup>II</sup> <sub>2</sub> (Esp) <sub>2</sub> ] Catalyst for Nitrogen Atom Transfer Reactions », ChemPhotoChem, vol. 1, nᵒ 12, p. 562-567, 2017.

  • R. Martin, F. Lacombat, A. Espagne, N. Dozova, P. Plaza, J. Yamamoto, P. Müller, K. Brettel, et A. de la Lande, « Ultrafast flavin photoreduction in an oxidized animal (6-4) photolyase through an unconventional tryptophan tetrad », Physical chemistry chemical physics: PCCP, sept. 2017.
    Résumé : Photolyases are flavoenzymes repairing UV-induced lesions in DNA, which may be activated by a photoreduction of their FAD cofactor. In most photolyases, this photoreduction proceeds by electron transfer along a chain of three tryptophan (Trp) residues, connecting the flavin to the protein surface. Much less studied, animal (6-4) photolyases (repairing pyrimidine-pyrimidone (6-4) photoproducts) are particularly interesting as they were recently shown to have a longer electron transfer chain, counting four Trp residues. Using femtosecond polarized transient absorption spectroscopy, we performed a detailed analysis of the photoactivation reaction in the (6-4) photolyase of Xenopus laevis with oxidized FAD. We showed that the excited flavin is very quickly reduced (∼0.5 ps) by a nearby tryptophan residue, yielding FAD˙(-) and WH˙(+) radicals. Subsequent kinetic steps in the picosecond regime were assigned to the migration of the positive charge along the Trp tetrad, in competition with charge recombination. We propose that the positive charge is actually delocalized over various Trp residues during most of the dynamics and that charge recombination essentially occurs through the proximal tryptophanyl radical. Oxidation of the fourth tryptophan is thought to be reached about as fast as that of the third one (∼40 ps), based on a comparison with a mutant protein lacking the distal Trp, implying ultrafast electron transfer between these two residues. This unusual mechanism sheds light on the rich diversity of electron transfer pathways found in various photolyases, and evolution-related cryptochromes alike.
    Mots-clés : B3S, LPB.

  • S. Mendes Marinho, M. - H. Ha-Thi, V. - T. Pham, A. Quaranta, T. Pino, C. Lefumeux, T. Chamaillé, W. Leibl, et A. Aukauloo, « Time-Resolved Interception of Multiple-Charge Accumulation in a Sensitizer-Acceptor Dyad », Angewandte Chemie (International Ed. in English), nov. 2017.
    Résumé : Biomimetic models that contain elements of photosynthesis are fundamental in the development of synthetic systems that can use sunlight to produce fuel. The critical task consists of running several rounds of light-induced charge separation, which is required to accumulate enough redox equivalents at the catalytic sites for the target chemistry to occur. Long-lived first charge-separated state and distinct electronic signatures for the sequential charge accumulated species are essential features to be able to track these events on a spectroscopic ground. Herein, we use a double-excitation nanosecond pump-pump-probe experiment to interrogate two successive rounds of photo-induced electron transfer on a molecular dyad containing a naphthalene diimide (NDI) linked to a [Ru(bpy)3 ](2+) (bpy=bipyridine) chromophore by using a reversible electron donor. We report an unprecedented long-lived two-electron charge accumulation (t=200 μs).
    Mots-clés : B3S, electron transfer, energy conversion, LPB, molecular dyads, photosynthesis, time-resolved spectroscopy.

  • A. Mezzetti et W. Leibl, « Time-resolved infrared spectroscopy in the study of photosynthetic systems », Photosynthesis Research, vol. 131, nᵒ 2, p. 121-144, févr. 2017.
    Résumé : Time-resolved (TR) infrared (IR) spectroscopy in the nanosecond to second timescale has been extensively used, in the last 30 years, in the study of photosynthetic systems. Interesting results have also been obtained at lower time resolution (minutes or even hours). In this review, we first describe the used techniques-dispersive IR, laser diode IR, rapid-scan Fourier transform (FT)IR, step-scan FTIR-underlying the advantages and disadvantages of each of them. Then, the main TR-IR results obtained so far in the investigation of photosynthetic reactions (in reaction centers, in light-harvesting systems, but also in entire membranes or even in living organisms) are presented. Finally, after the general conclusions, the perspectives in the field of TR-IR applied to photosynthesis are described.
    Mots-clés : B3S, Bacterial reaction centers, Carotenoids, Chlorophyll, Electron transfer, FTIR difference spectroscopy, Infrared, Kinetics, Light-harvesting systems, LPB, photosynthesis, Photosynthetic Reaction Center Complex Proteins, Photosystem I, Photosystem II, Proton transfer, Rapid-scan FTIR, Reaction centers, Rhodobacter sphaeroides, Spectroscopy, Fourier Transform Infrared, Step-scan FTIR, Thylakoids, Ubiquinone, Vibrational spectroscopy.

  • D. Moonshiram, A. Picón, A. Vazquez-Mayagoitia, X. Zhang, M. - F. Tu, P. Garrido-Barros, J. - P. Mahy, F. Avenier, et A. Aukauloo, « Elucidating light-induced charge accumulation in an artificial analogue of methane monooxygenase enzymes using time-resolved X-ray absorption spectroscopy », Chemical Communications (Cambridge, England), vol. 53, nᵒ 18, p. 2725-2728, févr. 2017.
    Résumé : We report the use of time-resolved X-ray absorption spectroscopy in the ns-μs time scale to track the light induced two electron transfer processes in a multi-component photocatalytic system, consisting of [Ru(bpy)3](2+)/ a diiron(iii,iii) model/triethylamine. EXAFS analysis with DFT calculations confirms the structural configurations of the diiron(iii,iii) and reduced diiron(ii,ii) states.
    Mots-clés : B3S, LPB.

  • M. Sensi, C. Baffert, L. Fradale, C. Gauquelin, P. Soucaille, I. Meynial-Salles, H. Bottin, L. de Gioia, M. Bruschi, V. Fourmond, C. Léger, et L. Bertini, « Photoinhibition of FeFe Hydrogenase », ACS Catalysis, vol. 7, nᵒ 10, p. 7378-7387, oct. 2017.

  • D. Sorigué, B. Légeret, S. Cuiné, S. Blangy, S. Moulin, E. Billon, P. Richaud, S. Brugière, Y. Couté, D. Nurizzo, P. Müller, K. Brettel, D. Pignol, P. Arnoux, Y. Li-Beisson, G. Peltier, et F. Beisson, « An algal photoenzyme converts fatty acids to hydrocarbons », Science (New York, N.Y.), vol. 357, nᵒ 6354, p. 903-907, sept. 2017.
    Résumé : Although many organisms capture or respond to sunlight, few enzymes are known to be driven by light. Among these are DNA photolyases and the photosynthetic reaction centers. Here, we show that the microalga Chlorella variabilis NC64A harbors a photoenzyme that acts in lipid metabolism. This enzyme belongs to an algae-specific clade of the glucose-methanol-choline oxidoreductase family and catalyzes the decarboxylation of free fatty acids to n-alkanes or -alkenes in response to blue light. Crystal structure of the protein reveals a fatty acid-binding site in a hydrophobic tunnel leading to the light-capturing flavin adenine dinucleotide (FAD) cofactor. The decarboxylation is initiated through electron abstraction from the fatty acid by the photoexcited FAD with a quantum yield >80%. This photoenzyme, which we name fatty acid photodecarboxylase, may be useful in light-driven, bio-based production of hydrocarbons.
    Mots-clés : B3S, LPB.

  • A. G. Tebo, A. Quaranta, C. Herrero, V. L. Pecoraro, et A. Aukauloo, « Intramolecular Photogeneration of a Tyrosine Radical in a Designed Protein », ChemPhotoChem, vol. 1, nᵒ 3, p. 89-92, mars 2017.
    Résumé : Long-distance biological electron transfer occurs through a hopping mechanism and often involves tyrosine as a high potential intermediate, for example in the early charge separation steps during photosynthesis. Protein design allows for the development of minimal systems to study the underlying principles of complex systems. Herein, we report the development of the first ruthenium-linked designed protein for the photogeneration of a tyrosine radical by intramolecular electron transfer.
    Mots-clés : B3S, Electron transfer, LPB, photochemistry, protein design, radicals, Tyrosine.

  • J. Yamamoto, P. Plaza, et K. Brettel, « Repair of (6-4) Lesions in DNA by (6-4) Photolyase: 20 Years of Quest for the Photoreaction Mechanism », Photochemistry and Photobiology, vol. 93, nᵒ 1, p. 51-66, 2017.

  • J. Yamamoto, K. Shimizu, T. Kanda, Y. Hosokawa, S. Iwai, P. Plaza, et P. Müller, « Loss of fourth electron-transferring tryptophan in animal (6-4) photolyase impairs DNA repair activity in bacterial cells », Biochemistry, sept. 2017.
    Résumé : (6-4) photolyases ((6-4)PLs) are flavoproteins that use blue light to repair the UV-induced pyrimidine(6-4)pyrimidone photoproduct in DNA. Their FAD cofactor can be reduced to its repair-active FADH- form by a photoinduced electron transfer reaction. In animal (6-4)PLs, a chain of four Trp residues was suggested to be involved in a step-wise transfer of an oxidation hole from the flavin to the surface of the protein. Here, we investigated the effect of mutation of the fourth Trp on the DNA photorepair activity of Xenopus laevis (6-4)PL (Xl64) in bacterial cells. The photoreduction and photorepair properties of this mutant protein were independently characterized in vitro. Our results demonstrate that the mutation of the fourth Trp in Xl64 drastically impairs the DNA repair activity in cells, and that this effect is due to the inhibition of the photoreduction process. We thereby show that the photoreductive formation of FADH- through the Trp tetrad is essential for the biological function of the animal (6-4)PL. The role of the Trp cascade, and of the fourth Trp in particular, are discussed.
    Mots-clés : B3S, LPB.


  • F. Cailliez, P. Müller, T. Firmino, P. Pernot, et A. de la Lande, « Energetics of Photoinduced Charge Migration within the Tryptophan Tetrad of an Animal (6-4) Photolyase », Journal of the American Chemical Society, vol. 138, nᵒ 6, p. 1904-1915, févr. 2016.
    Résumé : Cryptochromes and photolyases are flavoproteins that undergo cascades of electron/hole transfers after excitation of the flavin cofactor. It was recently discovered that animal (6-4) photolyases, as well as animal cryptochromes, feature a chain of four tryptophan residues, while other members of the family contain merely a tryptophan triad. Transient absorption spectroscopy measurements on Xenopus laevis (6-4) photolyase have shown that the fourth residue is effectively involved in photoreduction but at the same time could not unequivocally ascertain the final redox state of this residue. In this article, polarizable molecular dynamics simulations and constrained density functional theory calculations are carried out to reveal the energetics of charge migration along the tryptophan tetrad. Migration toward the fourth tryptophan is found to be thermodynamically favorable. Electron transfer mechanisms are sought either through an incoherent hopping mechanism or through a multiple sites tunneling process. The Jortner-Bixon formulation of electron transfer (ET) theory is employed to characterize the hopping mechanism. The interplay between electron transfer and relaxation of protein and solvent is analyzed in detail. Our simulations confirm that ET in (6-4) photolyase proceeds out of equilibrium. Multiple site tunneling is modeled with the recently proposed flickering resonance mechanism. Given the position of energy levels and the distribution of electronic coupling values, tunneling over three tryptophan residues may become competitive in some cases, although a hopping mechanism is likely to be the dominant channel. For both reactive channels, computed rates are very sensitive to the starting protein configuration, suggesting that both can take place and eventually be mixed, depending on the state of the system when photoexcitation takes place.
    Mots-clés : Animals, B3S, Deoxyribodipyrimidine Photo-Lyase, Electron Transport, LPB, Molecular Dynamics Simulation, Tryptophan.

  • K. Gibasiewicz, R. Białek, M. Pajzderska, J. Karolczak, G. Burdziński, M. R. Jones, et K. Brettel, « Weak temperature dependence of P + H A − recombination in mutant Rhodobacter sphaeroides reaction centers », Photosynthesis Research, vol. 128, nᵒ 3, p. 243-258, 2016.

  • P. Müller, K. Brettel, L. Grama, M. Nyitrai, et A. Lukacs, « Photochemistry of Wild-Type and N378D Mutant E. coli DNA Photolyase with Oxidized FAD Cofactor Studied by Transient Absorption Spectroscopy », Chemphyschem: A European Journal of Chemical Physics and Physical Chemistry, vol. 17, nᵒ 9, p. 1329-1340, mai 2016.
    Résumé : DNA photolyases (PLs) and evolutionarily related cryptochrome (CRY) blue-light receptors form a widespread superfamily of flavoproteins involved in DNA photorepair and signaling functions. They share a flavin adenine dinucleotide (FAD) cofactor and an electron-transfer (ET) chain composed typically of three tryptophan residues that connect the flavin to the protein surface. Four redox states of FAD are relevant for the various functions of PLs and CRYs: fully reduced FADH(-) (required for DNA photorepair), fully oxidized FADox (blue-light-absorbing dark state of CRYs), and the two semireduced radical states FAD(.-) and FADH(.) formed in ET reactions. The PL of Escherichia coli (EcPL) has been studied for a long time and is often used as a reference system; however, EcPL containing FADox has so far not been investigated on all relevant timescales. Herein, a detailed transient absorption study of EcPL on timescales from nanoseconds to seconds after excitation of FADox is presented. Wild-type EcPL and its N378D mutant, in which the asparagine facing the N5 of the FAD isoalloxazine is replaced by aspartic acid, known to protonate FAD(.-) (formed by ET from the tryptophan chain) in plant CRYs in about 1.5 μs, are characterized. Surprisingly, the mutant protein does not show this protonation. Instead, FAD(.-) is converted in 3.3 μs into a state with spectral features that are different from both FADH(.) and FAD(.-) . Such a conversion does not occur in wild-type EcPL. The chemical nature and formation mechanism of the atypical FAD radical in N378D mutant EcPL are discussed.
    Mots-clés : B3S, CPD photolyase, cryptochrome, Electron transfer, flavin radicals, LPB, Proton transfer.

  • J. S. Plegaria, C. Herrero, A. Quaranta, et V. L. Pecoraro, « Electron transfer activity of a de novo designed copper center in a three-helix bundle fold », Biochimica et Biophysica Acta (BBA) - Bioenergetics, vol. 1857, nᵒ 5, p. 522-530, 2016.


  • J. - F. Cornet, A. Aukauloo, F. Gloaguen, et W. Leibl, « Ingénierie de la photosynthèse artificielle. Verrous et perspectives », L’actualité chimique, p. 69-74, 2015.
    Résumé : La photosynthèse artificielle est une voie prometteuse pour obtenir des carburants stockables à partir d’énergie solaire et d’eau, voire aussi de CO2. Sa mise en œuvre nécessitera néanmoins de surmonter de nombreux verrous, relevant autant de la chimie et de la physique fondamentales que de l’ingénierie. Cet article fait le point sur l’ensemble des problématiques concernées, de l’échelle moléculaire à l’échelle du procédé, de façon intégrée. Il examine sous quelles conditions des performances énergétiques et cinétiques élevées pourront un jour être atteintes et ouvrir ainsi la voie au déploiement industriel à grande échelle de ces procédés de conversion de l’énergie solaire.
    Mots-clés : B3S, LPB.

  • D. de Bellefeuille, M. Orio, A. - L. Barra, A. Aukauloo, Y. Journaux, C. Philouze, X. Ottenwaelder, et F. Thomas, « Redox noninnocence of the bridge in copper(II) salophen and bis(oxamato) complexes », Inorganic Chemistry, vol. 54, nᵒ 18, p. 9013-9026, sept. 2015.
    Résumé : Two square-planar copper(II) complexes of 1,2-bis(2-hydroxy-3,5-di-tert-butylbenzimino)-4,5-bis(dimethylamino)benzene (1) and N-[4,5-bis(dimethylamino)-2-(oxalylamino)benzene]oxamate (2(2-)) were prepared. The crystal structures of the proligands H2L(1) and Et2H2L(2), as well as the corresponding complexes, are reported. The proligands each display a one-electron-oxidation wave, which is assigned to oxidation of the bis(dimethylamino)benzene moiety into a π radical. Complexes 1 and 2(2-) exhibit reversible one-electron-oxidation waves in their cyclic voltammograms (E1/2(1) = 0.14 and E1/2(2) = 0.31 V for 1 and E1/2(1) = -0.47 V vs Fc(+)/Fc for 2(2-)). The first process corresponds to oxidation of the bis(dimethylamino)benzene central ring into a π radical, while the second process for 1 is ascribed to oxidation of the π radical into an α-diiminoquinone. The one-electron-oxidized species 1(+) and 2(-) exhibit intense visible-near-IR absorptions, which are diagnostic of π radicals. They display a triplet signal in their electron paramagnetic resonance spectra, which stem from magnetic coupling between the ligand-radical spin and the copper(II) spin. The zero-field-splitting parameters are larger for 2(-) than 1(+) because of greater delocalization of the spin density onto the coordinated amidato N atoms. Density functional theory calculations support a π-radical nature of the one-electron-oxidized complexes, as well as S = 1 ground spin states. The electrogenerated 1(2+) comprises a closed-shell diiminoquinone ligand coordinated to a copper(II) metal center. Both 1 and 2 catalyze the aerobic oxidation of benzyl alcohol, albeit with different yields.
    Mots-clés : B3S, Benzyl Alcohol, Coordination Complexes, Copper, Electrochemistry, Electron Spin Resonance Spectroscopy, LPB, Molecular Structure, Oxamic Acid, Oxidation-Reduction, Salicylates.

  • C. Ducloiset, P. Jouin, E. Paredes, R. Guillot, M. Sircoglou, M. Orio, W. Leibl, et A. Aukauloo, « Monoanionic Dipyrrin-Pyridine Ligands: Synthesis, Structure and Photophysical Properties: Monoanionic Dipyrrin-Pyridine Ligands », European Journal of Inorganic Chemistry, vol. 2015, nᵒ 32, p. 5405-5410, 2015.

  • C. Herrero, A. Quaranta, M. Sircoglou, K. Sénéchal-David, A. Baron, I. M. Marín, C. Buron, J. - P. Baltaze, W. Leibl, A. Aukauloo, et F. Banse, « Successive light-induced two electron transfers in a Ru–Fe supramolecular assembly: from Ru–Fe(II)–OH2 to Ru–Fe(IV)–oxo », Chem. Sci., vol. 6, nᵒ 4, p. 2323-2327, 2015.

  • M. Malferrari, P. Turina, F. Francia, A. Mezzetti, W. Leibl, et G. Venturoli, « Dehydration affects the electronic structure of the primary electron donor in bacterial photosynthetic reaction centers: evidence from visible-NIR and light-induced difference FTIR spectroscopy », Photochem. Photobiol. Sci., vol. 14, nᵒ 2, p. 238-251, 2015.

  • P. Müller et J. - P. Bouly, « Searching for the mechanism of signalling by plant photoreceptor cryptochrome », FEBS letters, vol. 589, nᵒ 2, p. 189-192, janv. 2015.
    Résumé : Even though the plant photoreceptors cryptochromes were discovered more than 20 years ago, the mechanism through which they transduce light signals to their partner molecules such as COP1 (Constitutive Photomorphogenic 1) or SPA1 (Suppressor of Phytochrome A) still remains to be established. We propose that a negative charge induced by light in the vicinity of the flavin chromophore initiates cryptochrome 1 signalling. This negative charge might expel the protein-bound ATP from the binding pocket, thereby pushing off the C-terminus that covers the ATP pocket in the dark state of the protein. This conformational change should allow for phosphorylation of previously inaccessible amino acids. A partially phosphorylated 'ESSSSGRR-VPE' fragment of the C-terminus could mimic the sequence of the transcription factor HY5 that is essential for binding to the negative regulator of photomorphogenesis COP1. HY5 release through competition for the COP1 binding site could represent the long-sought connection between light activation of cryptochrome and modulation of photomorphogenesis.
    Mots-clés : ATP, B3S, Constitutive Photomorphogenic 1, Cryptochromes, HY5, LPB, Photoreceptor, Plant cryptochrome, Plant Proteins, plants, Protein Binding, Signal Transduction, Signalling, Transcription Factors.

  • P. Müller, J. Yamamoto, R. Martin, S. Iwai, et K. Brettel, « Discovery and functional analysis of a 4th electron-transferring tryptophan conserved exclusively in animal cryptochromes and (6-4) photolyases », Chem. Commun., vol. 51, nᵒ 85, p. 15502-15505, 2015.

  • C. Orain, L. Saujet, C. Gauquelin, P. Soucaille, I. Meynial-Salles, C. Baffert, V. Fourmond, H. Bottin, et C. Léger, « Electrochemical Measurements of the Kinetics of Inhibition of Two FeFe Hydrogenases by O2 Demonstrate That the Reaction Is Partly Reversible », Journal of the American Chemical Society, vol. 137, nᵒ 39, p. 12580-12587, oct. 2015.
    Résumé : The mechanism of reaction of FeFe hydrogenases with oxygen has been debated. It is complex, apparently very dependent on the details of the protein structure, and difficult to study using conventional kinetic techniques. Here we build on our recent work on the anaerobic inactivation of the enzyme [Fourmond et al. Nat. Chem. 2014, 4, 336-342] to propose and apply a new method for studying this reaction. Using electrochemical measurements of the turnover rate of hydrogenase, we could resolve the first steps of the inhibition reaction and accurately determine their rates. We show that the two most studied FeFe hydrogenases, from Chlamydomonas reinhardtii and Clostridium acetobutylicum, react with O2 according to the same mechanism, despite the fact that the former is much more O2 sensitive than the latter. Unlike often assumed, both enzymes are reversibly inhibited by a short exposure to O2. This will have to be considered to elucidate the mechanism of inhibition, before any prediction can be made regarding which mutations will improve oxygen resistance. We hope that the approach described herein will prove useful in this respect.
    Mots-clés : B3S, Catalytic Domain, Electrochemistry, Hydrogenase, Iron-Sulfur Proteins, Kinetics, LPB, Models, Molecular, Oxygen.

  • A. Quaranta, G. Charalambidis, C. Herrero, S. Margiola, W. Leibl, A. Coutsolelos, et A. Aukauloo, « Synergistic "ping-pong" energy transfer for efficient light activation in a chromophore-catalyst dyad », Physical chemistry chemical physics: PCCP, vol. 17, nᵒ 37, p. 24166-24172, oct. 2015.
    Résumé : The synthesis of a porphyrin-Ru(II) polypyridine complex where the porphyrin acts as a photoactive unit and the Ru(II) polypyridine as a catalytic precursor is described. Comparatively, the free base porphyrin was found to outperform the ruthenium based chromophore in the yield of light induced electron transfer. Mechanistic insights indicate the occurrence of a ping-pong energy transfer from the (1)LC excited state of the porphyrin chromophore to the (3)MCLT state of the catalyst and back to the (3)LC excited state of the porphyrin unit. The latter, triplet-triplet energy transfer back to the chromophore, efficiently competes with fast radiationless deactivation of the excited state at the catalyst site. The energy thus recovered by the chromophore allows improved yield of formation of the oxidized form of the chromophore and concomitantly of the oxidation of the catalytic unit by intramolecular charge transfer. The presented results are among the rare examples where a porphyrin chromophore is successfully used to drive an oxidative activation process where reductive processes prevail in the literature.
    Mots-clés : B3S, Catalysis, Energy Transfer, Light, LPB, Molecular Structure, Organometallic Compounds, Porphyrins, Pyridines, Ruthenium.

  • L. Schneider, Y. Mekmouche, P. Rousselot-Pailley, A. J. Simaan, V. Robert, M. Réglier, A. Aukauloo, et T. Tron, « Visible-Light-Driven Oxidation of Organic Substrates with Dioxygen Mediated by a [Ru(bpy)3 ](2+) /Laccase System », ChemSusChem, vol. 8, nᵒ 18, p. 3048-3051, sept. 2015.
    Résumé : Oxidation reactions are highly important chemical transformations that still require harsh reaction conditions and stoichiometric amounts of chemical oxidants that are often toxic. To circumvent these issues, olefins oxidation is achieved in mild conditions upon irradiation of an aqueous solution of the complex [Ru(bpy)3 ](2+) and the enzyme laccase. Epoxide formation is coupled to the light-driven reduction of O2 by [Ru(bpy)3 ](2+) /laccase system. The reactivity can be explained by dioxygen acting both as an oxidative agent and as renewable electron acceptor, avoiding the use of a sacrificial electron acceptor.
    Mots-clés : Alkenes, B3S, Copper, enzyme catalysis, Epoxy Compounds, Laccase, Light, LPB, Models, Molecular, olefins, Organometallic Compounds, Oxidants, oxidation, Oxidation-Reduction, Oxygen, Photochemical Processes, Protein Conformation, Ruthenium.
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Publications majeures avant 2015

-  Avenier F, Herrero C, Leibl W, Desbois A, Guillot R, Mahy JP, Aukauloo A (2013) Photoassisted Generation of a Dinuclear Iron(III) Peroxo Species Leading to Oxygen Atom Transfer Reaction
Angew. Chemie Int. Ed. 52, 3634-3637.

-  Herrero C, Costentin C, Aukauloo A (2011) Converting Photons to Electron and Proton Shifts from Water for Fuel Production. Molecular Solar Fuels. RSC Press, 39-84.

-  Herrero C, Batchelor L, Baron A, El Ghachtouli S, Sheth S, Guillot R, Vauzeilles B, Sircoglou M, Mallah T, Leibl W, Aukauloo A (2012) Click Chemistry as a Convenient Tool for the Incorporation of a Ruthenium Chromophore and a Nickel–Salen Monomer into a Visible-Light-Active Assembly. European Journal of Inorganic Chemistry, 2013, 494-499.

-  Baron A, Herrero C, Quaranta A, Leibl W, Vauzeilles B, Aukauloo A (2012) An efficient and versatile synthetic route for photoactive modular assemblies. Inorg. Chem. 51, 5985-5987.

-  Baron A, Herrero C, Quaranta A, Charlot MF, Leibl W, Vauzeilles B, Aukauloo A (2011) Efficient electron transfer through a triazole link in ruthenium(II) polypyridine type complexes. Chem. Comm. 47, 11011-11013.

-  Herrero C, Quaranta A, Leibl W, Rutherford AW, Aukauloo A (2011) Artificial photosynthetic systems. Using light and water to provide electrons and protons for the synthesis of a fuel. Energy and Environmental Chemistry 4, 2353-2365.

-  Herrero C, Quaranta A, Protti S, Leibl W, Rutherford AW, Fallahpour R, Charlot MF, Aukauloo A (2011) Light driven activation of the [H2O(terpy)MnIII-di-µ-oxo-MnIV(terpy)OH2] unit in a chromophore-catalyst complex. Chem. Asian J. 6 : 1335–1339

-  Herrero C, Hughes JL, Quaranta A, Cox N, Rutherford AW, Leibl W, Aukauloo A (2010) Intramolecular Light Induced Activation of a Salen-Mn(III) Complex by a Ruthenium Photosensitizer. Chemical Communications 46, 7605-7607.

-  Mezzetti A, Blanchet L, de Juan A, Leibl W, Ruckebusch C (2010) Ubiquinol formation in isolated photosynthetic reaction centers monitored by time-resolved differential FTIR in combination with 2D correlation spectroscopy and multivariate curve resolution. Anal. Bioanal. Chemistry, 399, 1999-2014.

-  Herrero C, Lassalle-Kaiser B, Leibl W, Rutherford AW, Aukauloo A (2008) Artificial systems related to light driven electron transfer processes in PSII. Coordination Chemistry Reviews 252, 456-468.

-  Fihri A, Artero A, Razavet M, Baffert C, Leibl W, Fontecave M (2008) Cobaloxime-Based Photocatalytic Devices for Hydrogen Production. Angew. Chemie Int. Ed. 47, 564–567.

-  Sybirna K, Ezanno P, Baffert C, Léger C, Bottin H (2013) Arginine171 of Chlamydomonas reinhardtii [Fe-Fe] hydrogenase HydA1 plays a crucial role in the electron transfer to its catalytic center. Int. Journal of Hydrogen Energy.

-  Baffert C, Sybirna K, Ezanno P, Lautier T, Hajj V, Meynial-Salles I, Soucaille P, Bottin H, Léger C (2012) Covalent Attachment of FeFe Hydrogenases to Carbon Electrodes for Direct Electron Transfer. Analytical Chemistry 84, 7999-8005.

-  Dutheil J., Saenkham P., Sakr S., Leplat C., Ortega-Ramos M., Bottin H., Cournac L., Cassier-Chauvat C., Chauvat F. (2012) The AbrB2 Autorepressor, Expressed from an Atypical Promoter, Represses the Hydrogenase Operon To Regulate Hydrogen Production in Synechocystis Strain PCC6803. Journal Of Bacteriology 194, 5423-5433.

-  Baffert C., Bertini L., Lautier T., Greco C., Sybirna K., Ezanno P., Etienne E., Soucaille P., Bertrand P., Bottin H., Meynial-Salles I., De Gioia L., Leger C.( 2011) CO Disrupts the Reduced H-Cluster of FeFe Hydrogenase. A Combined DFT and Protein Film Voltammetry Study. Journal Of The American Chemical Society 133, 2096-2099.

-  Shi L., Belchik S.M., Plymale A.E., Heald S., Dohnalkova A.C., Sybirna K., Bottin H., Squier T.C., Zachara J.M., Fredrickson J.K. (2011) Purification and Characterization of the [NiFe]-Hydrogenase of Shewanella oneidensis MR-1. Applied And Environmental Microbiology 77, 5584-5590.

-  Sybirna K., Antoine T., Lindberg P., Fourmond V., Rousset M., Mejean V., Bottin H. (2008) Shewanella oneidensis : a new and efficient system for expression and maturation of heterologous [Fe-Fe] hydrogenase from Chlamydomonas reinhardtii. Bmc Biotechnology 8.

-  Byrdin M, Villette S, Espagne A, Eker APM, Brettel K (2008) Polarized Transient Absorption To Resolve Electron Transfer between Tryptophans in DNA Photolyase. J Phys Chem B 112, 6866–6871.

-  Lukacs A, Eker APM, Byrdin M, Brettel K, Vos MH (2008) Electron Hopping through the 15 Å Triple Tryptophan Molecular Wire in DNA Photolyase Occurs within 30 ps. J Am Chem Soc 130, 14394-14395.

-  Byrdin M, Thiagarajan V, Villette S, Espagne A, Brettel K (2009) Use of ruthenium dyes for subnanosecond detector fidelity testing in real time transient absorption. Rev Sci Instrum 80, 043102.

-  Balland V, Byrdin M, Eker APM, Ahmad M, Brettel K (2009) What makes the difference between a cryptochrome and DNA photolyase ? A spectroelectrochemical comparison of the flavin redox transitions. J Am Chem Soc 131, 426-427.

-  Espagne A, Byrdin M, Eker APM, Brettel K (2009) Very Fast Product Release and Catalytic Turnover of DNA Photolyase. ChemBioChem 10, 1777-1780.

-  Byrdin M, Lukacs A, Thiagarajan V, Eker APM, Brettel K, Vos MH (2010) Quantum yield measurements of short-lived photoactivation intermediates in DNA photolyase : Toward a detailed understanding of the triple tryptophan electron transfer chain. J Phys Chem A 114, 3207–3214.

-  Thiagarajan V, Villette S, Espagne A, Eker APM, Brettel K, Byrdin M (2010) DNA repair by photolyase : A novel substrate with low background absorption around 265 nm for transient absorption studies in the UV. Biochemistry 49, 297-303.

-  Brettel K, Byrdin M (2010) Reaction mechanisms of DNA photolyase. Curr Opin Struct Biol 20, 693-701.

-  Chaves I, Pokorny R, Byrdin M, Hoang N, Ritz T, Brettel K, Essen L-O, van der Horst GTJ, Batschauer A, and Ahmad M (2011) The cryptochromes : blue light photoreceptors in plants and animals. Annu Rev Plant Biol 62, 335-364.

-  Gibasiewicz K, Pajzderska M, Potter J A, Fyfeb PK, Dobek A, Brettel K, Jones MR (2011) Mechanism of recombination of the P+HA– radical pair in mutant Rhodobacter sphaeroides reaction centers with modified free energy gaps between P+BA– and P+HA–. J Phys Chem B 115, 13037–13050.

-  Thiagarajan V, Byrdin M, Eker APM, Müller P, Brettel K (2011) Kinetics of cyclobutane thymine dimer splitting by DNA photolyase directly monitored in the UV. Proc Natl Acad Sci USA 10, 9402-9407.

-  Müller P, Brettel K (2012) [Ru(bpy)3]2+ as a reference in transient absorption spectroscopy : differential absorption coefficients for formation of the long-lived 3MLCT excited state. Photochem Photobiol Sci 11, 632-636.

-  Brettel K, Byrdin M (2012) DNA photolyase : Is the nonproductive back electron transfer really
much slower than forward transfer ? Proc Natl Acad Sci USA 109, E1462.

-  Yamamoto J, Martin R, Iwai S, Plaza P, Brettel K (2013) Repair of the (6-4) photoproduct by DNA photolyase requires two photons. Angew. Chemie Int. Ed. 52, 7432-7436.

-  Muller P, Bouly JP, Hitomi K, Balland V, Getzoff ED, Ritz T, Brettel K (2014) ATP binding turns plant cryptochromes into an efficient natural photoswitch. Sci. Reports 4, 5175.

-  Sheth S, Baron A, Herrero C, Vauzeilles B, Aukauloo A, Leibl W (2013) Light-induced Tryptophan radical generation in a click modular assembly of sensitizer-Tryptophan residue. Photochem. Photobiol. Sci. 12, 1074-1078.

-  Herrero C, Quaranta A, Fallahpour R, Leibl W, Aukauloo A (2013) Identification of the Different Mechanisms of Activation of a [RuII(tpy)(bpy)(OH2))2+ Catalyst by Modified Ruthenium Sensitizers in Supramolecular Complexes. J. Phys. Chem C, 117, 9605-9612.

-  Herrero C, Quaranta A, El Ghachtouli S, Vauzeilles B, Leibl W, Aukauloo A (2014) Carbon dioxide reduction via light activation of a ruthenium-Ni(cyclam) complex. Phys. Chem. Chem. Phys., 16, 12067-12072.

-  Malferrari M ; Turina P, Francia F, Mezzetti A, Leibl W, Venturoli G (2014) Dehydration affects the electronic structure of the primary electron donor in bacterial photosynthetic reaction centers : evidence from optical and light-induced difference FTIR spectroscopy. Photochem. Photobiol. Sci. in press.

-  Quaranta A, Qu H, Vencel T, Zhang Y, Leibl W, Leach S, Bensasson RW (2014) Photophysical properties in aqueous solutions of C60 embedded in 2:1 gamma-cyclodextrin/[60]fullerene inclusion complexes. Chemical Physics Letters 614:234-237.

-  Le Caër S, Klein G, Ortiz D, Lima M, Devineau S, Pin S, Brubach JB, Roy P, Pommeret S, Leibl W, Righini R, Renault JP (2014) Effect of myoglobin crowding on the dynamics of water : an infrared study. Phys. Chem. Chem. Phys. 16 : 22841-22852.

-  El Ghachtouli S, Guillot R, Leibl W, Aukauloo A (2014) Intramolecular Photoinduced Electron Transfer in Cobalt(II) Chlathrochelate-Zinc Porphyrin Assemblies Leading to Long-Lived Co(I) Species. Journal of Porphyrins and Phthalocyanines in press.

-  Fourmond V, Greco C, Sybirna K, Baffert C, Wang PH, Ezanno P, Montefiori M, Bruschi M, Meynial-Salles I, Soucaille P, Blumberger J, Bottin H, De Gioia L, Leger C (2014) The oxidative inactivation of FeFe hydrogenase reveals the flexibility of the H-cluster. Nat. Chem. 6, 336-342.

-  Malferrari M, Mezzetti A, Francia F, Venturoli G (2013) Effects of dehydration on light-induced conformational changes in bacterial photosynthetic reaction centers probed by optical and differential FTIR spectroscopy. Biochim. Biophys. Acta Bioenergetics 1827, 328-339.

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