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EPR and Mossbauer spectroscopic studies on enoate reductase

1996-01-01Artigo científico Acesso aberto
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dc.contributor.authorCaldeira, Jorge
dc.contributor.authorFeicht, Richard
dc.contributor.authorWhite, Hiltturd
dc.contributor.authorTeixeira, Miguel
dc.contributor.authorMoura, José J. G.
dc.contributor.authorSimon, Helmut
dc.contributor.authorMoura, Isabel
dc.contributor.institutionDQ - Departamento de Química
dc.contributor.institutionCQFB-REQUIMTE - Centro de Química Fina e Biotecnologia (Lab. Associado REQUIMTE)
dc.contributor.institutionInstituto de Tecnologia Química e Biológica António Xavier (ITQB)
dc.contributor.pblASBMB - American Society for Biochemistry and Molecular Biology
dc.date.accessioned2019-09-09T22:37:08Z
dc.date.available2019-09-09T22:37:08Z
dc.date.issued1996-01-01
dc.description.abstractEnoate reductase (EC 1.3.1.31) is a protein isolated from Clostridium tyrobutyricum that contains iron, labile sulfide, FAD, and FMN. The enzyme reduces the α,β carbon-carbon double bond of nonactivated 2-enoates and in a reversible way that of 2-enals at the expense of NADH or reduced methyl viologen. UV-visible and EPR potentiometric titrations detect a semiquinone species in redox intermediate states characterized by an isotropic EPR signal at g = 2.0 without contribution at 580 nm. EPR redox titration shows two widely spread mid-point redox potentials (-190 and -350 mV at pH 7.0), and a nearly stoichiometric amount of this species is detected. The data suggest the semiquinone radical has an anionic nature. In the reduced form, the [Fe- S] moiety is characterized by a single rhombic EPR spectrum, observed in a wide range of temperatures (4.2-60 K) with g values at 2.013, 1.943, and 1.860 (-180 mV at pH 7.0). The g(max) value is low when compared with what has been reported for other iron-sulfur clusters. Mossbauer studies reveal the presence of a [4Fe-4S](+2/+1) center. One of the subcomponents of the spectrum shows an unusually large value of quadrupole splitting (ferrous character) in both the oxidized and reduced states. Substrate binding to the reduced enzyme induces subtle changes in the spectroscopic Mossbauer parameters. The Mossbauer data together with known kinetic information suggest the involvement of this iron-sulfur center in the enzyme mechanism.en
dc.description.versionpublishersversion
dc.description.versionpublished
dc.format.extent6
dc.format.extent192340
dc.identifier.doi10.1074/jbc.271.31.18743
dc.identifier.issn0021-9258
dc.identifier.otherPURE: 14621077
dc.identifier.otherPURE UUID: c20d8404-df56-4936-9899-368d083af1c1
dc.identifier.otherScopus: 0029666154
dc.identifier.otherPubMed: 8702530
dc.identifier.otherWOS: A1996VB68300068
dc.identifier.otherORCID: /0000-0003-4124-6237/work/63725288
dc.identifier.otherORCID: /0000-0002-4726-2388/work/68772370
dc.identifier.urihttp://www.scopus.com/inward/record.url?scp=0029666154&partnerID=8YFLogxK
dc.identifier.urlhttps://www.scopus.com/pages/publications/0029666154
dc.language.isoeng
dc.peerreviewedyes
dc.subjectBiochemistry
dc.subjectMolecular Biology
dc.subjectCell Biology
dc.titleEPR and Mossbauer spectroscopic studies on enoate reductaseen
dc.typejournal article
degois.publication.firstPage18743
degois.publication.issue31
degois.publication.lastPage18748
degois.publication.titleJournal of Biological Chemistry
degois.publication.volume271
dspace.entity.typePublication
rcaap.rightsopenAccess

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