TAILIEUCHUNG - Báo cáo khoa học: ATP-dependent modulation and autophosphorylation of rapeseed 2-Cys peroxiredoxin

2-Cys peroxiredoxins (2-Cys Prx) are ubiquitous thiol-containing peroxidas-es that have been implicated in antioxidant defense and signal transduction. Although their biochemical features have been extensively studied, little is known about the mechanisms that link the redox activity and non-redox processes. | ễFEBS Journal ATP-dependent modulation and autophosphorylation of rapeseed 2-Cys peroxiredoxin Martin Aran1 Daniel Caporaletti1 Alejandro M. Senn1 Maria T. Tellez de Inon2 Maria R. Girotti1 Andrea S. Llera1 and Ricardo A. Wolosiuk1 1 Institute Leloir IIBBA-CONICET Universidad de Buenos Aires Argentina 2 INGEBI-CONICET Buenos Aires Argentina Keywords 2-Cys peroxiredoxin ATP binding autophosphorylation sulfinic-phosphoryl anhydride sulfonic-phosphorylanhydride Correspondence R. A. Wolosiuk Instituto Leloir Patricias Argentinas 435 C1405BWE Buenos Aires Argentina FaX 54 11 5238 7501 Tel 54 11 5238 7500 E-mail rwolosiuk@ Received 12 November 2007 revised 14 January 2008 accepted 16 January 2008 doi 2-Cys peroxiredoxins 2-Cys Prx are ubiquitous thiol-containing peroxidases that have been implicated in antioxidant defense and signal transduction. Although their biochemical features have been extensively studied little is known about the mechanisms that link the redox activity and non-redox processes. Here we report that the concerted action of a nucleoside triphosphate and Mg2 on rapeseed 2-Cys Prx reversibly impairs the peroxidase activity and promotes the formation of high molecular mass species. Using protein intrinsic fluorescence in the analysis of site-directed mutants we demonstrate that ATP quenches the emission intensity of Trp179 a residue close to the conserved Cys175. More importantly we found that ATP facilitates the autophosphorylation of 2-Cys Prx when the protein is successively reduced with thiol-bearing compounds and oxidized with hydroperoxides or quinones. MS analyses reveal that 2-Cys Prx incorporates the phosphoryl group into the Cys175 residue yielding the sulfinic-phosphoryl Prx- Cys175 -SO2PO32 and the sulfonic-phosphoryl Prx- Cys175 -SO3 PO32- anhydrides. Hence the functional coupling between ATP and 2-Cys Prx gives novel insights into not only the removal of reactive oxygen species but also .

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