A5036232057- Photosynthetic Processes and Mechanisms
- Photoreceptor and optogenetics research
- Hemoglobin structure and function
- Spectroscopy and Quantum Chemical Studies
- Heme Oxygenase-1 and Carbon Monoxide
- Light effects on plants
- Mass Spectrometry Techniques and Applications
- Neonatal Health and Biochemistry
- Electrochemical sensors and biosensors
- bioluminescence and chemiluminescence research
- Nitric Oxide and Endothelin Effects
- Photochemistry and Electron Transfer Studies
- Erythrocyte Function and Pathophysiology
- Electrochemical Analysis and Applications
- Laser-Matter Interactions and Applications
- Neural dynamics and brain function
- Protein Structure and Dynamics
- Mitochondrial Function and Pathology
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Porphyrin and Phthalocyanine Chemistry
- Photochromic and Fluorescence Chemistry
- Spectroscopy and Laser Applications
- Microbial Fuel Cells and Bioremediation
- Enzyme Structure and Function
École Polytechnique
2016-2025
Centre National de la Recherche Scientifique
2015-2024
Inserm
2015-2024
Université Paris-Saclay
2016-2022
Laboratoire d'Optique Appliquée
1998-2011
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
1997-2009
Ulrich Medical (Germany)
2009
Elisa (Finland)
2009
University of Essex
2009
Institut de Biologie et Technologies
2008-2009
Light makes light work of fatty acids Photosynthetic organisms are notable for their ability to capture energy and use it power biosynthesis. Some algae have gone a step beyond photosynthesis can initiate enzymatic photodecarboxylation acids, producing long-chain hydrocarbons. To understand this transformation, Sorigué et al. brought bear an array structural, computational, spectroscopic techniques fully characterized the catalytic cycle enzyme. These experiments consistent with mechanism...
It is shown that vibrational coherence modulates the femtosecond kinetics of stimulated emission and absorption reaction centers purple bacteria. In DLL mutant Rhodobacter capsulatus, which lacks bacteriopheophytin electron acceptor, oscillations with periods approximately 500 fs possibly also 2 ps were observed, are associated formation excited state. The kinetics, reflect primary processes in sphaeroides R-26, modulated by a period 700 at 796 nm 930 nm. latter case, nm, where state, P*,...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoherent Dynamics during the Primary Electron-Transfer Reaction in Membrane-Bound Centers of Rhodobacter sphaeroidesMarten H. Vos, Michael R. Jones, C. Neil Hunter, Jacques Breton, Jean-Christophe Lambry, and Jean-Louis MartinCite this: Biochemistry 1994, 33, 22, 6750–6757Publication Date (Print):June 7, 1994Publication History Published online1 May 2002Published inissue 7 June...
DNA photolyase is a photoactive flavoprotein that contains three tryptophan residues between the FAD cofactor and protein surface, solvent-exposed Trp being located 14.8 Å from flavin. Photoreduction of neutral radical FADH• form to catalytically active FADH− occurs via electron transfer through this chain. The first step in chain takes 30 ps, second less than 4 ps. Using combination site-directed mutagenesis femtosecond polarization spectroscopy discriminate spectroscopically...
A room-temperature study is reported of the femtosecond spectral evolution stimulated emission band primary electron-transfer precursor P* in bacterial photosynthesis. The was performed with membranes antenna-deficient RCO1 mutant Rhodobacter sphaeroides. time-dependent red shift, reflecting nuclear motion out Franck-Condon region excited state, resolved. Analysis oscillatory features persisting for > 1 ps kinetics revealed main frequencies activated motions at 30, 84, 145, and 192 cm-1....
In Escherichia coli photolyase, excitation of the FAD cofactor in its semireduced radical state (FADH*) induces an electron transfer over approximately 15 A from tryptophan W306 to flavin. It has been suggested that two additional tryptophans are involved chain FADH* <-- W382 W359 W306. To test this hypothesis, we have mutated into redox inert phenylalanine. Ultrafast transient absorption studies showed that, WT excited decayed with a time constant tau 26 ps fully reduced flavin and cation...
Cytochrome c (Cyt c) is a heme protein involved in electron transfer and also apoptosis. Its iron bisaxially ligated to histidine methionine side chains both ferric ferrous redox states are physiologically relevant, as well ligand exchange between internal residue external diatomic molecule. The photodissociation of axial was observed for several proteins including Cyt c, but no time-resolved studies have been reported on c. To investigate how the oxidation state influences primary...
The femtosecond spectral evolution of reaction centers Rhodobacter sphaeroides R-26 was studied at 10 K. Transient spectra in the near infrared region, obtained with 45-fs pulses (pump centered 870 nm and continuum probe pulses), were analyzed associated kinetics specific wavelengths. t = 0-fs transient spectrum is very rich structure; it contains separate induced bands 807 796 a bleaching 760 nm, reflecting strong changes interaction between all pigments upon formation excited state. A...
The interaction of mitochondrial cytochrome (cyt) c with cardiolipin (CL) is involved in the initial stages apoptosis. This can lead to destabilization heme-Met80 bond and peroxidase activity [Basova, L. V., et al. (2007) Biochemistry 46, 3423-3434]. We show that under these conditions carbon monoxide (CO) binds cyt c, very high affinity ( approximately 5 x 10(7) M(-1)), contrast native protein respiratory electron shuttling does not bind CO. Binding CO c-CL complex inhibits its activity....
Despite being highly toxic, carbon monoxide (CO) is also an essential intracellular signalling molecule. The mechanisms of CO-dependent cell are poorly defined, but likely to involve interactions with heme proteins. One such role for CO in ion channel regulation. Here, we examine the interaction KATP channels. We find that activates channels and binding a CXXHX16H motif on SUR2A receptor required increase activity. Spectroscopic kinetic data were used quantify ferrous heme-SUR2A complex....
Recently a novel class of reversible protein photoswitches has been discovered that is based on charge transfer (CT) complex composed the flavin cofactor and substrate‐analogue inhibitor molecule in family sarcosine oxidase flavoproteins. Here, excitation CT band results barrierless dissociation femtosecond timescale followed by its thermally activated reformation, few nanoseconds at ambient temperature. The photoreaction thought to involve well‐defined isomerization without from protein....
We demonstrate vibrational climbing in the CO stretch of carboxyhemoglobin pumped by midinfrared chirped ultrashort pulses. By use spectrally resolved pump-probe measurements, we directly observed induced absorption lines caused excited populations up to v = 6. In some cases, also stimulated emission, providing direct evidence population inversion. This study provides important spectroscopic parameters on strong-field regime, such as transition frequencies and dephasing times 6 7 transition....
Flow of excitation energy within the bacteriochlorin cofactor system bacterial reaction centers has been studied by multicolor transient absorption spectroscopy using differently shaped pulses 30 fs, both at room temperature and 15 K. This approach, which includes analysis free induction decay signals, helps to disentangle processes electronic dephasing, transfer, internal conversion, nuclear motion, all taking place on time scale ∼100 fs. Part excitations (estimated 80−90% temperature) flow...
The fabrication of microcomponents or microstructured surfaces with conventional manufacturing methods - such as turning, milling drilling imposes high demands on the machine behavior. requirements in terms characteristics are currently met by only few ultraprecision tools. A broad range materials as, for example, non-ferrous metals plastics can be machined, producing real three-dimensional structures an optical surface quality
Femtosecond spectroscopy was used to study vibrational dynamics in the first singlet excited state (P*) of primary donor bacterial reaction centers (RC)in which electron transfer have been altered by single amino acid modifications. We studied intracytoplasmic RC-only membranes containing Rhodobacter sphaeroides wild-type RCs and bearing mutations vicinity P, where Tyr M210 modified His, Leu, Trp Phe L181 Tyr. These do not change frequencies main low-frequency activated modes, is consistent...