ID   ARSM_CLOSP              Reviewed;         270 AA.
AC   A0A0D3MJQ5;
DT   12-APR-2017, integrated into UniProtKB/Swiss-Prot.
DT   27-MAY-2015, sequence version 1.
DT   03-AUG-2022, entry version 19.
DE   RecName: Full=Arsenite methyltransferase {ECO:0000303|PubMed:25790486};
DE            EC=2.1.1.137 {ECO:0000269|PubMed:25790486};
GN   Name=arsM {ECO:0000303|PubMed:25790486};
OS   Clostridium sp.
OC   Bacteria; Firmicutes; Clostridia; Eubacteriales; Clostridiaceae;
OC   Clostridium.
OX   NCBI_TaxID=1506;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, CATALYTIC ACTIVITY, AND
RP   MUTAGENESIS OF CYS-65; CYS-153 AND CYS-203.
RC   STRAIN=BXM;
RX   PubMed=25790486; DOI=10.1093/femsle/fnu003;
RA   Wang P.P., Bao P., Sun G.X.;
RT   "Identification and catalytic residues of the arsenite methyltransferase
RT   from a sulfate-reducing bacterium, Clostridium sp. BXM.";
RL   FEMS Microbiol. Lett. 362:1-8(2015).
CC   -!- FUNCTION: Catalyzes the transfer of a methyl group from AdoMet to
CC       arsenite, producing methylated arsenicals. Involved in the conversion
CC       of As(III) to monomethylarsenic and the conversion of monomethylarsenic
CC       to dimethylarsenic. Reduces the arsenic toxicity in the cell and may
CC       contribute to the global arsenic cycling.
CC       {ECO:0000269|PubMed:25790486}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[thioredoxin]-dithiol + arsenic triglutathione + 2 H2O + S-
CC         adenosyl-L-methionine = [thioredoxin]-disulfide + 3 glutathione +
CC         H(+) + methylarsonous acid + S-adenosyl-L-homocysteine;
CC         Xref=Rhea:RHEA:69460, Rhea:RHEA-COMP:10698, Rhea:RHEA-COMP:10700,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:17826,
CC         ChEBI:CHEBI:29950, ChEBI:CHEBI:50058, ChEBI:CHEBI:57856,
CC         ChEBI:CHEBI:57925, ChEBI:CHEBI:59789, ChEBI:CHEBI:183640;
CC         EC=2.1.1.137; Evidence={ECO:0000269|PubMed:25790486};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 [thioredoxin]-dithiol + arsenic triglutathione + H2O + 2 S-
CC         adenosyl-L-methionine = 2 [thioredoxin]-disulfide + dimethylarsinous
CC         acid + 3 glutathione + 2 H(+) + 2 S-adenosyl-L-homocysteine;
CC         Xref=Rhea:RHEA:69464, Rhea:RHEA-COMP:10698, Rhea:RHEA-COMP:10700,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:23808,
CC         ChEBI:CHEBI:29950, ChEBI:CHEBI:50058, ChEBI:CHEBI:57856,
CC         ChEBI:CHEBI:57925, ChEBI:CHEBI:59789, ChEBI:CHEBI:183640;
CC         EC=2.1.1.137; Evidence={ECO:0000269|PubMed:25790486};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=3 [thioredoxin]-dithiol + arsenic triglutathione + 3 S-
CC         adenosyl-L-methionine = 3 [thioredoxin]-disulfide + 3 glutathione + 3
CC         H(+) + 3 S-adenosyl-L-homocysteine + trimethylarsine;
CC         Xref=Rhea:RHEA:69432, Rhea:RHEA-COMP:10698, Rhea:RHEA-COMP:10700,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:27130, ChEBI:CHEBI:29950,
CC         ChEBI:CHEBI:50058, ChEBI:CHEBI:57856, ChEBI:CHEBI:57925,
CC         ChEBI:CHEBI:59789, ChEBI:CHEBI:183640; EC=2.1.1.137;
CC         Evidence={ECO:0000269|PubMed:25790486};
CC   -!- SIMILARITY: Belongs to the methyltransferase superfamily. Arsenite
CC       methyltransferase family. {ECO:0000305}.
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DR   EMBL; KJ801487; AIM18906.1; -; Genomic_DNA.
DR   AlphaFoldDB; A0A0D3MJQ5; -.
DR   SMR; A0A0D3MJQ5; -.
DR   BRENDA; 2.1.1.137; 1515.
DR   GO; GO:0030791; F:arsenite methyltransferase activity; IEA:UniProtKB-EC.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   GO; GO:0046685; P:response to arsenic-containing substance; IEA:UniProtKB-KW.
DR   Gene3D; 3.40.50.150; -; 1.
DR   InterPro; IPR026669; Arsenite_MeTrfase-like.
DR   InterPro; IPR025714; Methyltranfer_dom.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   PANTHER; PTHR43675; PTHR43675; 1.
DR   Pfam; PF13847; Methyltransf_31; 1.
DR   SUPFAM; SSF53335; SSF53335; 1.
PE   1: Evidence at protein level;
KW   Arsenical resistance; Methyltransferase; S-adenosyl-L-methionine;
KW   Transferase.
FT   CHAIN           1..270
FT                   /note="Arsenite methyltransferase"
FT                   /id="PRO_0000439593"
FT   MUTAGEN         65
FT                   /note="C->S: Cannot methylate arsenite, but can still
FT                   methylate monomethylarsenic."
FT                   /evidence="ECO:0000269|PubMed:25790486"
FT   MUTAGEN         153
FT                   /note="C->S: Lack of activity."
FT                   /evidence="ECO:0000269|PubMed:25790486"
FT   MUTAGEN         203
FT                   /note="C->S: Lack of activity."
FT                   /evidence="ECO:0000269|PubMed:25790486"
SQ   SEQUENCE   270 AA;  29061 MW;  0EBD5A2F604B8404 CRC64;
     MDNIREGVRQ KYAFAIANRG QGCCGSPGCC SDGLSDAADP ITGNLYDESD LQGLDPELIA
     NSFGCGNPTA LMNLNLGEVV LDLGSGSGLD VLLSAKRVGP TGKAYGLDMT DEMLAVAKEN
     QRKSGIENAE FLKGHIEEIP LAAKSIDVII SNCVINLSGD KDKVLKEAYR VLKPQGRFAV
     SDIVIKRPLP EKIRDNILAW AGCIAGAMTE EEYRGKLSRA GFENISLQVT REYNLEDPSL
     RGMLEDLTDG EIKEFQGAMV SCFIRAAKPA