Structural highlights
FunctionA8MI53_ALKOO Has an important function as a repair enzyme for proteins that have been inactivated by oxidation. Catalyzes the reversible oxidation-reduction of methionine sulfoxide in proteins to methionine (By similarity).[HAMAP-Rule:MF_01401] Publication Abstract from PubMedClostridium oremlandii MsrA (CoMsrA) is a natively selenocysteine-containing methionine-S-sulfoxide reductase and classified into a 1-Cys type MsrA. CoMsrA exists as a monomer in solution. Herein, we report evidence that CoMsrA can undergo homodimerization during catalysis. The monomeric CoMsrA dimerizes in the presence of its substrate methionine sulfoxide via an intermolecular disulfide bond between catalytic Cys16 residues. The dimeric CoMsrA is resolved by the reductant glutaredoxin, suggesting the relevance of dimerization in catalysis. The dimerization reaction occurs in a concentration- and time-dependent manner. In addition, the occurrence of homodimer formation in the native selenoprotein CoMsrA is confirmed. We also determine the crystal structure of the dimeric CoMsrA, having the dimer interface around the two catalytic Cys16 residues. A central cone-shaped hole is present in the surface model of dimeric structure, and the two Cys16 residues constitute the base of the hole. Collectively, our biochemical and structural analyses suggest a novel dimerization-mediated mechanism for CoMsrA catalysis that is additionally involved in CoMsrA regeneration by glutaredoxin. Evidence for the Dimerization-Mediated Catalysis of Methionine Sulfoxide Reductase A from Clostridium oremlandii.,Lee EH, Lee K, Kwak GH, Park YS, Lee KJ, Hwang KY, Kim HY PLoS One. 2015 Jun 24;10(6):e0131523. doi: 10.1371/journal.pone.0131523., eCollection 2015. PMID:26107511[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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