Peptide methionine sulfoxide reductase (MsrA) reverses the oxidative damage to both free methionine and methionine within a protein by catalysing the metal/cofactor independent reduction of the sulphoxide moiety. The reducing equivalents are provided by either DTT or a thioredoxin-regenerating system. The structure of MrsA is of a mixed alpha/beta type, with a two-layer alpha-beta sandwich motif at its core.
Methionine oxidation is a serious problem for cells. It can lead to inviability of the cells if it goes on unchecked, and even in systems where MsrA s present methionine oxidation is still a major cause of random cell damage and has been implicated in a variety of neuro-generative deceases, emphysema, cataractogenesis, rheumatoid arthritis and other general ageing processes.
Defined by 7 residues: CYS:A-60 [auth A-72]TYR:A-91 [auth A-103]GLU:A-103 [auth A-115]ASP:A-138 [auth A-150]TYR:A-143 [auth A-155]CYS:A-206 [auth A-218]CYS:A-215 [auth A-227]