Diastereoselective reduction of protein-bound methionine sulfoxide by methionine sulfoxide reductase

Structure of Mycobacterium tuberculosis methionine sulfoxide reductase A in complex with protein-bound methionine.

Peptide methionine sulfoxide reductase (MsrA) repairs oxidative damage to methionine residues arising from reactive oxygen species and reactive nitrogen intermediates. MsrA activity is found in a wide variety of organisms, and it is implicated as one of the primary defenses against oxidative stress. Disruption of the gene encoding MsrA in several pathogenic bacteria responsible for infections i...

Selenium and Methionine Sulfoxide Reduction.

Selenium is an essential trace element because it is present in proteins in the form of selenocysteine residue. Functionally characterized selenoproteins are oxidoreductases. Selenoprotein methionine-R-sulfoxide reductase B1 (MsrB1) is a repair enzyme that reduces ROS-oxidized methionine residues in proteins. Here, we explored a possibility that reversible methionine oxidation is also a mechani...

Complex with Protein-Bound Methionine Methionine Sulfoxide Reductase A in Mycobacterium tuberculosis

Reduction of methionine sulfoxide to methionine by Escherichia coli.

L-Methionine-dl-sulfoxide can support the growth of an Escherichia coli methionine auxotroph, suggesting the presence of an enzyme(s) capable of reducing the sulfoxide to methionine. This was verified by showing that a cell-free extract of E. coli catalyzes the conversion of methionine sulfoxide to methionine. This reaction required reduced nicotinamide adenine dinucleotide phosphate and a gene...

Methionine sulfoxide reductase A is a stereospecific methionine oxidase.

Methionine sulfoxide reductase A (MsrA) catalyzes the reduction of methionine sulfoxide to methionine and is specific for the S epimer of methionine sulfoxide. The enzyme participates in defense against oxidative stresses by reducing methionine sulfoxide residues in proteins back to methionine. Because oxidation of methionine residues is reversible, this covalent modification could also functio...