CATH Classification

Domain Context

CATH Clusters

Superfamily Peptide methionine sulfoxide reductase.
Functional Family Peptide methionine sulfoxide reductase MsrB

Enzyme Information

1.8.4.12
Peptide-methionine (R)-S-oxide reductase.
based on mapping to UniProt P0A3Q9
Peptide-L-methionine + thioredoxin disulfide + H(2)O = peptide-L- methionine (R)-S-oxide + thioredoxin.
-!- The reaction occurs in the reverse direction to that shown above. -!- Exhibits high specificity for reduction of the R-form of methionine S-oxide, with higher activity being observed with L-methionine S-oxide than with D-methionine S-oxide. -!- While both free and protein-bound methionine (R)-S-oxide act as substrates, the activity with the peptide-bound form is far greater. -!- Plays a role in preventing oxidative-stress damage caused by reactive oxygen species by reducing the oxidized form of methionine back to methionine and thereby reactivating peptides that had been damaged. -!- The reaction proceeds via a sulfenic-acid intermediate. -!- For MsrB2 and MsrB3, thioredoxin is a poor reducing agent but thionein works well.
1.8.4.11
Peptide-methionine (S)-S-oxide reductase.
based on mapping to UniProt P0A3Q9
(1) Peptide-L-methionine + thioredoxin disulfide + H(2)O = peptide-L- methionine (S)-S-oxide + thioredoxin. (2) L-methionine + thioredoxin disulfide + H(2)O = L-methionine (S)-S- oxide + thioredoxin.
-!- The reaction occurs in the reverse direction to that shown above. -!- Exhibits high specificity for the reduction of the S-form of L-methionine S-oxide, acting faster on the residue in a peptide than on the free amino acid. -!- On the free amino acid, it can also reduce D-methionine (S)-S-oxide but more slowly. -!- Plays a role in preventing oxidative-stress damage caused by reactive oxygen species by reducing the oxidized form of methionine back to methionine and thereby reactivating peptides that had been damaged. -!- The reaction proceeds via a sulfenic-acid intermediate. -!- Formerly EC 1.8.4.6.

UniProtKB Entries (1)

P0A3Q9
MSAB1_STRPN
Streptococcus pneumoniae TIGR4
Peptide methionine sulfoxide reductase MsrA/MsrB 1

PDB Structure

PDB 3E0M
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Structural and Kinetic Analysis of an MsrA-MsrB Fusion Protein from Streptococcus pneumoniae
Kim, Y.K., Shin, Y.J., Lee, W.-H., Kim, H.-Y., Hwang, K.Y.
Mol.Microbiol.