Investigation of the active site of the (FeFe) hydrogenase from Desulfovibrio desulfuricans [Elektronische Ressource] / vorgelegt von Alexey Evgenievich Silakov

Investigation of the active siteof the [FeFe] hydrogenase fromDesulfovibrio desulfuricansInaugural-DissertationzurErlangung des Doktorgrades der¨Mathematisch-Naturwissenschaftlichen Fakultatder Heinrich-Heine-Universitat¨ Dusseldorf¨vorgelegt vonAlexey Evgenievich Silakovaus der Russischen Foderation¨Dusseldorf¨ 2007angefertigt amMax-Planck-Institut fur¨ Bioanorganische Chemiein Mulheim¨ an der Ruhrunter Anteilung von Dr. E.Reijerse und Prof.Dr. W.Lubitz.Gedruckt mit der Genehmigung derMathematisch-Naturwissenschaftlichen Fakultat¨der Heinrich-Heine-Universitat¨ Dusseldorf¨Referent: Prof. Dr. W. LubitzKoreferent: Prof. Dr. G. Buldt¨Tag der mundlichen¨ Prufung:¨ 17. 01. 2007AbstractAlexey Evgenievich SilakovHydrogen plays an important role in the metabolism of certain microorganisms, where+ −the reaction H 2H + 2e is catalyzed by metalloenzymes called hydrogenases. The2active site of the [FeFe] hydrogenase (the so called H-cluster) contains a classical [4Fe4S]cluster connected via the sulphur of a cysteine residue to a bi-nuclear cluster. The [2Fe]Hsubcluster is coordinated by CO and CN ligands, which stabilize metals in low-oxidationstates.Several states of the active site can be detected using EPR. The oxidized form of theH-cluster (H ) shows a very characteristic rhombic EPR spectrum. The distal iron of theox[2Fe] subcluster has an exchangeable coordination site.