Autophosphorylation of rapeseed 2-cys-peroxiredoxin”

ARAN M., CAPORALETTI D., SENN A., TÉLLEZ-IÑÓN M.T., GIROTTI, M.R., LLERA A.S., WOLOSIUK R.A.|

Mar del Plata, RA

Congreso; XLIII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology (SAIB).; 2007

Argentine Society for Biochemistry and Molecular Biology (SAIB).

2-Cys peroxiredoxins(2-Cys Prx) are widely distributed thiol-containing peroxidases that have been implicated in various cellular processes.We have used functional and structural approaches to demonstrate tha rapessed 2-Cys Prx is a direct target for nucleotides.The concerted action of a nucleoside triphosphate and Mg+2 impairs reversibly the peroxidase activity, being purine derivatives more efficient than the pyrimidine counterparts. In particular, structural and site-directed mutagenesis studies are consistent with a mechanism where ATP interacts non -covalently with a region that contains the conserved Cys175. Most importantly, ATP triggers the autophosphorylation of 2-CysPrx upon reduction with thiol-bearing compounds or phosphines followed by oxidation with hydroxides, quinones, tetrathionate, selenate or diamide. Mass spectrometry analysis reveals that 2-cys Prx incorporates the phosphoryl moiety into the Cys175 residue yielding the sulfinic-phosphoryl [Prx-(Cys175)-SO2PO3 ]2 and the sulfonic-phosphoryl[Prx-(Cys175)-SO3PO3]2 anhydrides. hence, teh functional coupling between ATP and 2-Cys Prx brings novel insights not only to the removal of toxic reactive oxigen species but also to mechanisms that link the status of cell energy to the oxidation of reactive cyseine residues.