title: Relativistic DFT calculation of the reaction cycle intermediates of [NiFe] hydrogenase: a contribution to understanding the enzymatic mechanism.
abstract: Structures and spectroscopic observables of the paramagnetic intermediates of the enzymatic reaction cycle of the metalloenzyme [NiFe] hydrogenase were calculated using relativistic density functional theory (DFT) within the zero-order regular approximation (ZORA). By comparing experimental and calculated magnetic resonance parameters (g- and hyperfine tensors) for the states Ni-A, Ni-B, Ni-C, Ni-L, and Ni-CO the details of the atomic composition of these paramagnetic intermediates could be elucidated that are mostly not available from X-ray structure analysis. In general, good agreement between calculated and experimental observables could be obtained. A detailed picture of the changes of the active center during the catalytic cycle was deduced from the obtained structures. Based on these results, a consistent model for the sequence of redox states including protonation steps is proposed which is important for understanding the mechanism of the [NiFe] hydrogenase.
authors.affiliation: Max-Volmer-Laboratorium für Biophysikalische Chemie, Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stein
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lubitz
mesh_terms: D002248:Carbon Monoxide / Q000494:pharmacology; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D045286:Desulfovibrio gigas / Q000201:enzymology; D004578:Electron Spin Resonance Spectroscopy; D006864:Hydrogenase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction
chemical_list: D002248:Carbon Monoxide; C043296:nickel-iron hydrogenase; D006864:Hydrogenase