Methylpurine-DNA glycosylase (IPR003180)

Short name: MPG

Overlapping homologous superfamilies

Family relationships



Methylpurine-DNA glycosylase (MPG, or alkyladenine DNA glycosylase (AAG)) is a base excision-repair protein, catalyzing the first step in base excision repair by cleaving damaged DNA bases within double-stranded DNA to produce an abasic site. MPG bends DNA by intercalating between the base pairs, causing the damaged base to flip out of the double helix and into the enzyme active site for cleavage. It is responsible for the hydrolysis of the deoxyribose N-glycosidic bond, excising 3-methyladenine and 3-methylguanine from damaged DNA [PMID: 18191412, PMID: 10440863, PMID: 11554308, PMID: 9790531, PMID: 11106395, PMID: 14567703, PMID: 14688248, PMID: 15990363, PMID: 12077143, PMID: 14555760, PMID: 12323378]. Its action is induced by alkylating chemotherapeutics, as well as deaminated and lipid peroxidation-induced purine adducts [PMID: 17768096]. MPG without an N-terminal extension excises hypoxanthine with one-third of the efficiency of full-length MPG under similar conditions, suggesting that is function may largely be attributable to the N-terminal extension [PMID: 17716976].

Although AAG represents one of six DNA glycosylase classes, it lacks the helix-hairpin-helix active site motif associated with other base excision repair glycosylases and is structurally distinct from them.

GO terms

Biological Process

GO:0006284 base-excision repair

Molecular Function

GO:0003677 DNA binding
GO:0003905 alkylbase DNA N-glycosylase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.