Transferases;
Transferring one-carbon groups;
Methyltransferases
BRITE hierarchy

DNA-6-O-methylguanine/DNA-4-O-methylthymine:[protein]-L-cysteine S-methyltransferase

(1) DNA (containing 6-O-methylguanine) + protein L-cysteine = DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine [RN:R04314];
(2) DNA (containing 4-O-methylthymine) + protein L-cysteine = DNA (without 4-O-methylthymine) + protein S-methyl-L-cysteine

R04314
Reaction

DNA containing 6-O-methylguanine [CPD:C04250];
protein L-cysteine [CPD:C02743];
DNA [CPD:C00039]

This protein is involved in the repair of methylated DNA. Unlike EC 3.2.2.20, DNA-3-methyladenine glycosidase I and EC 3.2.2.21, DNA-3-methyladenine glycosidase II, which remove the methylated base leaving an apurinic/apyrimidinic site, this enzyme transfers the methyl group from the methylated DNA to an internal cysteine residue, leaving an intact nucleotide. Since the methyl transfer is irreversible, the enzyme can only catalyse a single turnover.

EC 2.1.1.63 created 1982, modified 1983, modified 1999, modified 2003, modified 2017