title: Rates of intra- and intermolecular electron transfers in hydrogenase deduced from steady-state activity measurements.
abstract: Electrons are transferred over long distances along chains of FeS clusters in hydrogenases, mitochondrial complexes, and many other respiratory enzymes. It is usually presumed that electron transfer is fast in these systems, despite the fact that there has been no direct measurement of rates of FeS-to-FeS electron transfer in any respiratory enzyme. In this context, we propose and apply to NiFe hydrogenase an original strategy that consists of quantitatively interpreting the variations of steady-state activity that result from changing the nature of the FeS clusters which connect the active site to the redox partner, and/or the nature of the redox partner. Rates of intra- and intermolecular electron transfer are deduced from such large data sets. The mutation-induced variations of electron transfer rates cannot be explained by changes in intercenter distances and reduction potentials. This establishes that FeS-to-FeS rate constants are extremely sensitive to the nature and coordination of the centers.
authors: Laboratoire de Bioénergétique et Ingénierie des Protéines, CNRS UPR 9036, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors: Sébastien
authors: S
authors: Dementin
authors: Bénédicte
authors: B
authors: Burlat
authors: Vincent
authors: V
authors: Fourmond
authors: Fanny
authors: F
authors: Leroux
authors: Pierre-Pol
authors: PP
authors: Liebgott
authors: Abbas
authors: A
authors: Abou Hamdan
authors: Christophe
authors: C
authors: Léger
authors: Marc
authors: M
authors: Rousset
authors: Bruno
authors: B
authors: Guigliarelli
authors: Patrick
authors: P
authors: Bertrand