A5045264710- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Photosynthetic Processes and Mechanisms
- Metal-Catalyzed Oxygenation Mechanisms
- Metal complexes synthesis and properties
- Electron Spin Resonance Studies
- Spectroscopy and Quantum Chemical Studies
- Trace Elements in Health
- Nitric Oxide and Endothelin Effects
- Porphyrin and Phthalocyanine Chemistry
- Electrochemical Analysis and Applications
- Alzheimer's disease research and treatments
- Photoreceptor and optogenetics research
- Science, Research, and Medicine
- Hemoglobin structure and function
- Innovation, Sustainability, Human-Machine Systems
- Prion Diseases and Protein Misfolding
- Magnetism in coordination complexes
- Photochemistry and Electron Transfer Studies
- Electrocatalysts for Energy Conversion
- Free Radicals and Antioxidants
- Ion channel regulation and function
- Metalloenzymes and iron-sulfur proteins
- Crystal structures of chemical compounds
- Crystallography and molecular interactions
Aix-Marseille Université
2019-2025
Centre National de la Recherche Scientifique
2015-2024
Bioénergétique et Ingénierie des Protéines
2020-2024
Institut de Microbiologie de la Méditerranée
2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2011-2021
CEA Paris-Saclay
2010-2021
Université Paris-Saclay
2008-2021
Institut de Biologie Intégrative de la Cellule
2016-2021
Institut de Biologie et Technologies
2008-2020
Université Paris-Sud
2005-2018
The electronic structures of the native Mn4OxCa cluster and biosynthetically substituted Mn4OxSr oxygen evolving complex (OEC) photosystem II (PSII) core complexes isolated from Thermosynechococcus elongatus, poised in S2 state, were studied by X- Q-band CW-EPR pulsed 55Mn-ENDOR spectroscopy. Both wild type tyrosine D less mutants grown photoautotrophically either CaCl2 or SrCl2 containing media measured. obtained spectra state displayed characteristic, clearly noticeable differences...
Ligand sphere revealed: Cu ions were proposed to be linked the aggregation of amyloid-β peptide in Alzheimer's disease. However, unambiguous identification ligands has remained difficult. The use various EPR spectroscopies with specific isotopic labeling now allowed assignment CuII for both complexes present at physiological pH value (see 3D plots and structures). results indicate that peptide's first two amino acids are important coordination probably aggregation. Detailed facts importance...
The Gly-His-Lys (GHK) peptide and the Asp-Ala-His-Lys (DAHK) sequences are naturally occurring high-affinity copper(II) chelators found in blood plasma hence of biological interest. A structural study copper complexes these peptides was conducted solid state solution by determining their X-ray structures, using a large range spectroscopies, including EPR HYSCORE (hyperfine sub-level correlation), absorption (1)H (13)C NMR spectroscopy. results indicate that structures [Cu(II)(DAHK)] similar...
A new series of six Schiff bases derived from S-methyldithiocarbazate (SMDTC) and S-benzyldithiocarbazate (SBDTC) with methyl levulinate (SMML, SBML), levulinic acid (SMLA, SBLA), 4-carboxybenzaldehyde (SM4CB, SB4CB) were reacted copper(II), producing complexes general formula ML2 (M = Cu(II), L ligand). All compounds characterized using established physicochemical spectroscopic methods. Crystal structures determined for three SBML, SBLA) two Cu(II) (Cu(SMML)2 Cu(SMLA)2). In order to provide...
Artificial photosynthesis: The first photoelectron trade between P680 and the TyrZ–His190 pair of Photosystem II was modeled by a ruthenium(II) trisbipyridine type complex that contains phenol hydrogen atom bonded to an imidazole group. photogenerated phenoxyl radical has been characterized. This opens up way for more complete biomimetic model II. Supporting information this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2005/z461948_s.pdf or from author. Please...
Despite crystallographic structures now available and intensive work in the past decades, little is known about higher redox states of catalytic cycle Photosystem II, enzyme responsible for presence O2 on Earth at beginning process that has produced both biomass fossil fuels. In one highest oxidation states, S3-state, only signals g-values than 4 have been detected so far X-band. this work, we report first time complete X-band EPR spectrum S3-state II. Simulations show that, a spin state S =...
The surface oxidation site (Trp-171) in lignin peroxidase (LiP) required for the reaction with veratryl alcohol a high-redox-potential (1.4 V) substrate, was engineered into Coprinus cinereus (CiP) by introducing Trp residue heme that has similar protein fold but lacks this activity. To create catalytic activity toward CiP, it necessary to reproduce and its negatively charged microenvironment means of triple mutation. resulting D179W+R258E+R272D variant characterized multifrequency EPR...
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a glycolytic enzyme that also functions in transcriptional regulation, oxidative stress, vesicular trafficking, and apoptosis. Because GAPDH required for the insertion of cellular heme into inducible nitric oxide synthase [Chakravarti, R., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 18004–18009], we extensively characterized binding properties GAPDH. Substoichiometric amounts ferric bound to (one per tetramer) form low-spin complex...
Heme iron has many and varied roles in biology. Most commonly it binds as a prosthetic group to proteins, been widely supposed amply demonstrated that subtle variations the protein structure around heme, including heme ligands, are used control reactivity of metal ion. However, role biology now appears also include regulatory responsibility cell; this includes regulation ion channel function. In work, we show cardiac KATP channels regulated by heme. We identify cytoplasmic heme-binding...
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....
ATP-binding cassette (ABC) transporters are ubiquitous membrane proteins responsible for the translocation of a wide diversity substrates across biological membranes. Some them confer multidrug or antimicrobial resistance to cancer cells and pathogenic microorganisms, respectively. Despite wealth structural data gained in last two decades, molecular mechanism these efflux pumps remains elusive, including extent separation between nucleotide-binding domains (NBDs) during transport cycle....
In the present work we report reactivity of [LMnII]2+ toward addition hydrogen peroxide (H2O2) in acetonitrile solution, where L is a pentadentate polypyridine ligand. Formation peroxo complexes evidenced by low-temperature UV–visible spectroscopy, ESI-mass spectrometry, and EPR spectroscopy using parallel as well perpendicular mode detection. The influence medium (basicity, water content) on formation various species investigated. basic nonanhydrous fate reaction mixture solution di-μ-oxo...
The Kae1 (Kinase-associated endopeptidase 1) protein is a member of the recently identified transcription complex EKC and telomeres maintenance KEOPS in yeast. homologues are encoded by all sequenced genomes three domains life. Although annotated as putative endopeptidases, actual functions these universal proteins unknown. Here we show that purified (Pa-Kae1) from Pyrococcus abyssi an iron-protein with novel type ATP-binding site. Surprisingly, this did not exhibit activity vitro but binds...
The flavoprotein Cytochrome P450 reductase (CPR) is the unique electron pathway from NADPH to (CYPs). conformational dynamics of human CPR in solution, which involves transitions a "locked/closed" an "unlocked/open" state, crucial for transfer. To date, however, factors guiding these changes remain unknown. By Site-Directed Spin Labelling coupled Electron Paramagnetic Resonance spectroscopy, we have incorporated non-canonical amino acid onto flavin mononucleotide (FMN) and adenine...
Abstract Understanding protein structure requires studying its dynamics, which is critical to elucidating functional role. Biophysical techniques have revolutionized this field over time, providing remarkable insights into structure‐function relationships. Among these, Site‐Directed Spin Labelling (SDSL) combined with Electron Paramagnetic Resonance (EPR) a powerful method delivering structural data at the residue level, irrespective of size or environment. Traditional nitroxide labels...
Multifrequency (95, 190, and 285 GHz) high-field electron paramagnetic resonance (EPR) spectroscopy has been used to characterize radical intermediates in wild-type Trp191Gly mutant cytochrome c peroxidase (CcP). The EPR spectra of the exchange-coupled oxoferryl−trytophanyl pair that constitutes CcP compound I intermediate [(Fe(IV)O) Trp•+] were analyzed using a spin Hamiltonian incorporated general anisotropic spin−spin interaction term. Perturbation expressions this derived, their...
The photosynthetic oxidation of water to oxygen occurs in photosystem II (PSII) at an active site composed a tetranuclear cluster manganese ions, redox tyrosine, YZ, and two essential cofactors, calcium chloride. Recently, several experimental observations have led the proposal metalloradical catalytic cycle which via hydrogen-atom abstraction by tyrosyl radical from bound cluster. This model predicts close proximity between Yz•, Mn involvement bifurcated hydrogen bond. Magnetic resonance...