1xw3
From Proteopedia
Crystal Structure of Human Sulfiredoxin (Srx)
Structural highlights
Function[SRXN1_HUMAN] Contributes to oxidative stress resistance by reducing cysteine-sulfinic acid formed under exposure to oxidants in the peroxiredoxins PRDX1, PRDX2, PRDX3 and PRDX4. Does not act on PRDX5 or PRDX6. May catalyze the reduction in a multi-step process by acting both as a specific phosphotransferase and a thioltransferase.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSufiredoxins (Srx) repair the inactivated forms of typical two-Cys peroxiredoxins (Prx) implicated in hydrogen peroxide-mediated cell signaling. The reduction of the cysteine sulfinic acid moiety within the active site of the Prx by Srx involves novel sulfur chemistry and the use of ATP and Mg(2+). The 1.65 A crystal structure of human Srx (hSrx) exhibits a new protein fold and a unique nucleotide binding motif containing the Gly98-Cys99-His100-Arg101 sequence at the N-terminus of an alpha-helix. HPLC analysis of the reaction products has confirmed that the site of ATP cleavage is between the beta- and gamma-phosphate groups. Cys99 and the gamma-phosphate of ATP, modeled within the active site of the 2.0 A ADP product complex structure, are adjacent to large surface depressions containing additional conserved residues. These features and the necessity for significant remodeling of the Prx structure suggest that the interactions between hSrx and typical two-Cys Prxs are specific. Moreover, the concave shape of the hSrx active site surface appears to be ideally suited to interacting with the convex surface of the toroidal Prx decamer. Structural basis for the retroreduction of inactivated peroxiredoxins by human sulfiredoxin.,Jonsson TJ, Murray MS, Johnson LC, Poole LB, Lowther WT Biochemistry. 2005 Jun 21;44(24):8634-42. PMID:15952770[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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