Show simple item record

dc.contributor.authorHorta, Bruno Brasil
dc.contributor.authorde Oliveira, Marcos Antonio [UNESP]
dc.contributor.authorDiscola, Karen Fulan
dc.contributor.authorRosa Cussiol, Jose Renato
dc.contributor.authorSoares Netto, Luis Eduardo
dc.identifier.citationJournal of Biological Chemistry. Bethesda: Amer Soc Biochemistry Molecular Biology Inc, v. 285, n. 21, p. 16051-16065, 2010.
dc.description.abstractThe phytopathogenic bacterium Xylella fastidiosa is the etiological agent of various plant diseases. To survive under oxidative stress imposed by the host, microorganisms express antioxidant proteins, including cysteine-based peroxidases named peroxiredoxins. This work is a comprehensive analysis of the catalysis performed by PrxQ from X. fastidiosa (XfPrxQ) that belongs to a peroxiredoxin class still poorly characterized and previously considered as moderately reactive toward hydroperoxides. Contrary to these assumptions, our competitive kinetics studies have shown that the second-order rate constants of the peroxidase reactions of XfPrxQ with hydrogen peroxide and peroxynitrite are in the order of 107 and 106 M(-1) s(-1), respectively, which are as fast as the most efficient peroxidases. The XfPrxQ disulfides were only slightly reducible by dithiothreitol; therefore, the identification of a thioredoxin system as the probable biological reductant of XfPrxQ was a relevant finding. We also showed by site-specific mutagenesis and mass spectrometry that an intramolecular disulfide bond between Cys-47 and Cys-83 is generated during the catalytic cycle. Furthermore, we elucidated the crystal structure of XfPrxQ C47S in which Ser-47 and Cys-83 lie similar to 12.3 angstrom apart. Therefore, significant conformational changes are required for disulfide bond formation. In fact, circular dichroism data indicated that there was a significant redox-dependent unfolding of alpha-helices, which is probably triggered by the peroxidatic cysteine oxidation. Finally, we proposed a model that takes data from this work as well data as from the literature into account.en
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipLaboratório Nacional de Luz Síncrotron (LNLS)
dc.publisherAmer Soc Biochemistry Molecular Biology Inc
dc.relation.ispartofJournal of Biological Chemistry
dc.sourceWeb of Science
dc.titleStructural and Biochemical Characterization of Peroxiredoxin Q beta from Xylella fastidiosa CATALYTIC MECHANISM and HIGH REACTIVITYen
dcterms.rightsHolderAmer Soc Biochemistry Molecular Biology Inc
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.description.affiliationUniv São Paulo, Dept Genet & Biol Evolut, Inst Biociencias, BR-05508900 São Paulo, Brazil
dc.description.affiliationUniv Estadual Paulista, Dept Biol, BR-11330900 Sao Vicente, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Dept Biol, BR-11330900 Sao Vicente, Brazil
dc.rights.accessRightsAcesso restrito
dc.description.sponsorshipIdLNLS: D03B-MX1 7568
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Biociências, São Vicentept
Localize o texto completo

Files in this item


There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record