Cofactor composition and function of a H2-sensing regulatory hydrogenase as revealed by Mossbauer and EPR spectroscopy

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dc.contributor.authorRoncaroli, Federico
dc.contributor.authorBill, Eckhard
dc.contributor.authorFriedrich, Bärbel
dc.contributor.authorLenz, Oliver
dc.contributor.authorLubitz, Wolfgang
dc.contributor.authorPandelia, Maria-Eirini
dc.date.accessioned2017-10-25T06:25:23Z
dc.date.available2017-10-25T06:25:23Z
dc.date.issued2015
dc.description.abstractThe regulatory hydrogenase (RH) from Ralstonia eutropha H16 acts as a sensor for the detection of environmental H-2 and regulates gene expression related to hydrogenase-mediated cellular metabolism. In marked contrast to prototypical energy-converting [NiFe] hydrogenases, the RH is apparently insensitive to inhibition by O-2 and CO. While the physiological function of regulatory hydrogenases is well established, little is known about the redox cycling of the [NiFe] center and the nature of the iron-sulfur (FeS) clusters acting as electron relay. The absence of any FeS cluster signals in EPR had been attributed to their particular nature, whereas the observation of essentially only two active site redox states, namely Ni-SI and Ni-C, invoked a different operant mechanism. In the present work, we employ a combination of Mossbauer, FTIR and EPR spectroscopic techniques to study the RH, and the results are consistent with the presence of three [4Fe-4S] centers in the small subunit. In the as-isolated, oxidized RH all FeS clusters reside in the EPR-silent 2+ state. Incubation with H2 leads to reduction of two of the [4Fe-4S] clusters, whereas only strongly reducing agents lead to reduction of the third cluster, which is ascribed to be the [4Fe-4S] center in 'proximal' position to the [NiFe] center. In the two different active site redox states, the low-spin FeII exhibits distinct Mossbauer features attributed to changes in the electronic and geometric structure of the catalytic center. The results are discussed with regard to the spectral characteristics and physiological function of H-2-sensing regulatory hydrogenases.en
dc.description.sponsorshipDFG, EXC 314, Unifying Concepts in Catalysisen
dc.identifier.eissn2041-6539
dc.identifier.issn2041-6520
dc.identifier.urihttps://depositonce.tu-berlin.de/handle/11303/6948
dc.identifier.urihttp://dx.doi.org/10.14279/depositonce-6287
dc.language.isoen
dc.rights.urihttps://creativecommons.org/licenses/by/3.0/
dc.subject.ddc540 Chemie und zugeordnete Wissenschaftende
dc.titleCofactor composition and function of a H2-sensing regulatory hydrogenase as revealed by Mossbauer and EPR spectroscopyen
dc.typeArticleen
dc.type.versionpublishedVersionen
dcterms.bibliographicCitation.doi10.1039/c5sc01560j
dcterms.bibliographicCitation.issue8
dcterms.bibliographicCitation.journaltitleChemical Scienceen
dcterms.bibliographicCitation.originalpublishernameRoyal Society of Chemistryde
dcterms.bibliographicCitation.originalpublisherplaceCambridgede
dcterms.bibliographicCitation.pageend4507
dcterms.bibliographicCitation.pagestart4495
dcterms.bibliographicCitation.volume6
tub.accessrights.dnbfree
tub.affiliationFak. 2 Mathematik und Naturwissenschaften::Inst. Chemie::FG Physikalische Chemie / Biophysikalische Chemiede
tub.affiliation.facultyFak. 2 Mathematik und Naturwissenschaftende
tub.affiliation.groupFG Physikalische Chemie / Biophysikalische Chemiede
tub.affiliation.instituteInst. Chemiede
tub.publisher.universityorinstitutionTechnische Universität Berlin

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