methylated-DNA-protein-cysteine methyltransferase; 6-O-methylguanine-DNA methyltransferase; MGMT; O-6-methylguanine-DNA-alkyltransferase (MGMT)

Function

• DNA repair protein
• O6-MGMT removes carcinogen induced O6-methylguanine adducts from DNA which result in G -> A mutations if left unrepaired
• stoichiometrically transfers the methyl group at the O-6 position to a Cys in the enzyme; this is a suicide reaction: the enzyme is irreversibly inactivated (thus technically not an enzyme)

DNA (containing 6-O-methylguanine) + protein L-cysteine = DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine

Cofactor: binds 1 Zn+2

Structure

belongs to the MGMT family

Compartment

nucleus

Pathology

• promoter hypermethylation of the gene & epigenetic silencing is associated with colon, lung, lymphoid & other tumors

More general terms

• O-methyl transferase
• DNA-binding protein
• phosphoprotein

Database

• OMIM: https://mirror.omim.org/entry/156569
• UniProt: http://www.uniprot.org/uniprot/P16455.html