Structure and mechanism of peptide methionine sulfoxide reductase, an "anti-oxidation" enzyme.
Peptide methionine sulfoxide reductase (MsrA) reverses oxidative damage to both free methionine and methionine within proteins. As such, it helps protect the host organism against stochastic damage that can contribute to cell death. The structure of bovine MsrA has been determined in two different modifications, both of which provide different insights into the biology of the protein. There are three cysteine residues located in the vicinity of the active site. Conformational changes in a glycine-rich C-terminal tail appear to allow all three thiols to come together and to participate in catalysis. The structures support a unique, thiol-disulfide exchange mechanism that relies upon an essential cysteine as a nucleophile and additional conserved residues that interact with the oxygen atom of the sulfoxide moiety.
Lowther
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WT
Institute of Molecular Biology, Howard Hughes Medical Institute and Department of Physics, University of Oregon, Eugene, Oregon 97403, USA.
Brot
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N
Weissbach
H
H
Matthews
B W
BW
D000818:Animals; D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D018360:Crystallography, X-Ray; D004229:Dithiothreitol / Q000737:chemistry; D004735:Energy Transfer; D051150:Methionine Sulfoxide Reductases; D008958:Models, Molecular; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013879:Thioredoxins / Q000737:chemistry
D000975:Antioxidants; D013879:Thioredoxins; D010088:Oxidoreductases; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase; D004229:Dithiothreitol