ID   MSRAB_STRGC             Reviewed;         311 AA.
AC   Q9LAM9; A8AUY7;
DT   02-MAY-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2000, sequence version 1.
DT   10-JUN-2026, entry version 133.
DE   RecName: Full=Peptide methionine sulfoxide reductase MsrA/MsrB;
DE   Includes:
DE     RecName: Full=Peptide methionine sulfoxide reductase MsrA;
DE              Short=Protein-methionine-S-oxide reductase;
DE              EC=1.8.4.11;
DE     AltName: Full=Peptide-methionine (S)-S-oxide reductase;
DE              Short=Peptide Met(O) reductase;
DE   Includes:
DE     RecName: Full=Peptide methionine sulfoxide reductase MsrB;
DE              EC=1.8.4.12;
DE     AltName: Full=Peptide-methionine (R)-S-oxide reductase;
GN   Name=msrAB; Synonyms=msrA; OrderedLocusNames=SGO_0278;
OS   Streptococcus gordonii (strain Challis / ATCC 35105 / BCRC 15272 / CH1 /
OS   DL1 / V288).
OC   Bacteria; Bacillati; Bacillota; Bacilli; Lactobacillales; Streptococcaceae;
OC   Streptococcus.
OX   NCBI_TaxID=467705;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND FUNCTION.
RX   PubMed=10678908; DOI=10.1128/iai.68.3.1061-1068.2000;
RA   Vriesema A.J.M., Dankert J., Zaat S.A.J.;
RT   "A shift from oral to blood pH is a stimulus for adaptive gene expression
RT   of Streptococcus gordonii CH1 and induces protection against oxidative
RT   stress and enhanced bacterial growth by expression of msrA.";
RL   Infect. Immun. 68:1061-1068(2000).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Challis / ATCC 35105 / BCRC 15272 / CH1 / DL1 / V288;
RX   PubMed=17720781; DOI=10.1128/jb.01023-07;
RA   Vickerman M.M., Iobst S., Jesionowski A.M., Gill S.R.;
RT   "Genome-wide transcriptional changes in Streptococcus gordonii in response
RT   to competence signaling peptide.";
RL   J. Bacteriol. 189:7799-7807(2007).
CC   -!- FUNCTION: Has an important function as a repair enzyme for proteins
CC       that have been inactivated by oxidation. Catalyzes the reversible
CC       oxidation-reduction of methionine sulfoxide in proteins to methionine
CC       (By similarity). Involved in protection against oxidative stress when
CC       the bacterium enters the host bloodstream and required for maximal
CC       growth under aerobic and anaerobic conditions. {ECO:0000250,
CC       ECO:0000269|PubMed:10678908}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-methionyl-[protein] + [thioredoxin]-disulfide + H2O = L-
CC         methionyl-(S)-S-oxide-[protein] + [thioredoxin]-dithiol;
CC         Xref=Rhea:RHEA:14217, Rhea:RHEA-COMP:10698, Rhea:RHEA-COMP:10700,
CC         Rhea:RHEA-COMP:12313, Rhea:RHEA-COMP:12315, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:16044, ChEBI:CHEBI:29950, ChEBI:CHEBI:44120,
CC         ChEBI:CHEBI:50058; EC=1.8.4.11;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[thioredoxin]-disulfide + L-methionine + H2O = L-methionine
CC         (S)-S-oxide + [thioredoxin]-dithiol; Xref=Rhea:RHEA:19993, Rhea:RHEA-
CC         COMP:10698, Rhea:RHEA-COMP:10700, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:29950, ChEBI:CHEBI:50058, ChEBI:CHEBI:57844,
CC         ChEBI:CHEBI:58772; EC=1.8.4.11;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-methionyl-[protein] + [thioredoxin]-disulfide + H2O = L-
CC         methionyl-(R)-S-oxide-[protein] + [thioredoxin]-dithiol;
CC         Xref=Rhea:RHEA:24164, Rhea:RHEA-COMP:10698, Rhea:RHEA-COMP:10700,
CC         Rhea:RHEA-COMP:12313, Rhea:RHEA-COMP:12314, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:16044, ChEBI:CHEBI:29950, ChEBI:CHEBI:45764,
CC         ChEBI:CHEBI:50058; EC=1.8.4.12;
CC   -!- SIMILARITY: In the N-terminal section; belongs to the MsrA Met
CC       sulfoxide reductase family. {ECO:0000305}.
CC   -!- SIMILARITY: In the C-terminal section; belongs to the MsrB Met
CC       sulfoxide reductase family. {ECO:0000305}.
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DR   EMBL; AF128264; AAF36477.1; -; Genomic_DNA.
DR   EMBL; CP000725; ABV11083.1; -; Genomic_DNA.
DR   RefSeq; WP_011999808.1; NC_009785.1.
DR   AlphaFoldDB; Q9LAM9; -.
DR   SMR; Q9LAM9; -.
DR   STRING; 467705.SGO_0278; -.
DR   KEGG; sgo:SGO_0278; -.
DR   eggNOG; COG0225; Bacteria.
DR   eggNOG; COG0229; Bacteria.
DR   HOGENOM; CLU_031040_1_0_9; -.
DR   BRENDA; 1.8.4.12; 5934.
DR   Proteomes; UP000001131; Chromosome.
DR   GO; GO:0005737; C:cytoplasm; IEA:TreeGrafter.
DR   GO; GO:0033744; F:L-methionine (S)-S-oxide reductase activity; IEA:RHEA.
DR   GO; GO:0033743; F:peptide-methionine (R)-S-oxide reductase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0008113; F:peptide-methionine (S)-S-oxide reductase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0030091; P:protein repair; IEA:InterPro.
DR   GO; GO:0006979; P:response to oxidative stress; IEA:InterPro.
DR   FunFam; 3.30.1060.10:FF:000007; Peptide methionine sulfoxide reductase msrA/msrB; 1.
DR   FunFam; 2.170.150.20:FF:000003; Peptide methionine sulfoxide reductase MsrB; 1.
DR   Gene3D; 2.170.150.20; Peptide methionine sulfoxide reductase; 1.
DR   Gene3D; 3.30.1060.10; Peptide methionine sulphoxide reductase MsrA; 1.
DR   HAMAP; MF_01401; MsrA; 1.
DR   HAMAP; MF_01400; MsrB; 1.
DR   InterPro; IPR002569; Met_Sox_Rdtase_MsrA_dom.
DR   InterPro; IPR036509; Met_Sox_Rdtase_MsrA_sf.
DR   InterPro; IPR028427; Met_Sox_Rdtase_MsrB.
DR   InterPro; IPR002579; Met_Sox_Rdtase_MsrB_dom.
DR   InterPro; IPR011057; Mss4-like_sf.
DR   NCBIfam; TIGR00401; msrA; 1.
DR   NCBIfam; TIGR00357; peptide-methionine (R)-S-oxide reductase MsrB; 1.
DR   PANTHER; PTHR10173; METHIONINE SULFOXIDE REDUCTASE; 1.
DR   PANTHER; PTHR10173:SF60; PEPTIDE METHIONINE SULFOXIDE REDUCTASE MSRA_MSRB 1; 1.
DR   Pfam; PF01625; PMSR; 1.
DR   Pfam; PF01641; SelR; 1.
DR   SUPFAM; SSF51316; Mss4-like; 1.
DR   SUPFAM; SSF55068; Peptide methionine sulfoxide reductase; 1.
DR   PROSITE; PS51790; MSRB; 1.
PE   3: Inferred from homology;
KW   Multifunctional enzyme; Oxidoreductase; Reference proteome.
FT   CHAIN           1..311
FT                   /note="Peptide methionine sulfoxide reductase MsrA/MsrB"
FT                   /id="PRO_0000138516"
FT   DOMAIN          172..295
FT                   /note="MsrB"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01126"
FT   REGION          1..155
FT                   /note="Peptide methionine sulfoxide reductase A"
FT   ACT_SITE        10
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        284
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01126"
SQ   SEQUENCE   311 AA;  35672 MW;  7D4B7CAF81DBE692 CRC64;
     MAEIYLAGGC FWGLEEYFSR IEGVKKTTVG YANGQVESTN YQLIHQTDHA ETVHLIYDEK
     RVSLREILLY YFRVIDPLSV NKQGNDVGRQ YRTGVYYTNQ ADKAVIEQVF AEQEKQLGQK
     IAVELEPLRH YVLAEDYHQD YLKKNPGGYC HINVNDAYQP LVDPGQYEKP TDAELKEQLT
     QEQYQVTQLS ATERPFHNAY NATFEEGIYV DVTTGEPLFF AGDKFESGCG WPSFSRPIAR
     EVLRYYEDKS HGMERIEVRS RSGNAHLGHV FTDGPESAGG LRYCINSAAL RFIPKEKMEA
     EGYAYLLQHM K
//