title: Mechanism of O2diffusion and reduction in FeFe hydrogenases.
abstract: FeFe hydrogenases are the most efficient H2-producing enzymes. However, inactivation by O2remains an obstacle that prevents them being used in many biotechnological devices. Here, we combine electrochemistry, site-directed mutagenesis, molecular dynamics and quantum chemical calculations to uncover the molecular mechanism of O2diffusion within the enzyme and its reactions at the active site. We propose that the partial reversibility of the reaction with O2results from the four-electron reduction of O2to water. The third electron/proton transfer step is the bottleneck for water production, competing with formation of a highly reactive OH radical and hydroxylated cysteine. The rapid delivery of electrons and protons to the active site is therefore crucial to prevent the accumulation of these aggressive species during prolonged O2exposure. These findings should provide important clues for the design of hydrogenase mutants with increased resistance to oxidative damage.
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.|Institute of Physical Chemistry, Polish Academy of Science, ul. Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Kubas
authors.affiliation: Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Marseille, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Orain
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.|CIC nanoGUNE, Tolosa Hiribidea 76, 20018 Donostia-San Sebastián, Spain.|IKERBASQUE; Basque Foundation for Science, María Díaz de Haro 3, 48013 Bilbao, Spain.
authors.forename: David
authors.initials: D
authors.lastname: De Sancho
authors.affiliation: Institut de Biologie et de Technologies de Saclay IBITECS, SB2SM, F-91191 Gif sur Yvette, France.|Institut de Biologie Intégrative de la Cellule I2BC, UMR 9198, CEA, CNRS, Université Paris Sud, F-91191 Gif sur Yvette, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Saujet
authors.affiliation: Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Marseille, France.
authors.forename: Matteo
authors.initials: M
authors.lastname: Sensi
authors.affiliation: Université de Toulouse, INSA, UPS, INP, LISBP, INRA:UMR792, CNRS:UMR 5504, 135 avenue de Rangueil, Toulouse 31077 Cedex 04, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Gauquelin
authors.affiliation: Université de Toulouse, INSA, UPS, INP, LISBP, INRA:UMR792, CNRS:UMR 5504, 135 avenue de Rangueil, Toulouse 31077 Cedex 04, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Meynial-Salles
authors.affiliation: Université de Toulouse, INSA, UPS, INP, LISBP, INRA:UMR792, CNRS:UMR 5504, 135 avenue de Rangueil, Toulouse 31077 Cedex 04, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Soucaille
authors.affiliation: Institut de Biologie et de Technologies de Saclay IBITECS, SB2SM, F-91191 Gif sur Yvette, France.|Institut de Biologie Intégrative de la Cellule I2BC, UMR 9198, CEA, CNRS, Université Paris Sud, F-91191 Gif sur Yvette, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Bottin
authors.affiliation: Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Marseille, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Baffert
authors.affiliation: Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Marseille, France.
authors.forename: Vincent
authors.identifier: 0000-0001-9837-6214
authors.initials: V
authors.lastname: Fourmond
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Best
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Jochen
authors.initials: J
authors.lastname: Blumberger
authors.affiliation: Aix Marseille Univ, CNRS, Laboratoire de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée, Marseille, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Léger
mesh_terms: D002384:Catalysis; D003013:Clostridium / Q000201:enzymology; D004058:Diffusion; D055664:Electrochemical Techniques; D006859:Hydrogen / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry* / Q000235:genetics; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D006859:Hydrogen; D006864:Hydrogenase; D010100:Oxygen