Fpg Protein from Escherichia coli

General description

Formamidopyrimidine-DNA glycosylase (Fpg) is a DNA repair enzyme found in Escherichia coli, which contains one zinc atom. Proximal to its C-terminal, it contains a zinc-finger motif of CC/CC type.

Fpg contains two domains separated by a flexible hinge.

Research area: Cell signaling

Application

Fpg Protein from Escherichia coli has been used for the assessment of DNA oxidative damage using comet assay.

Biochem/physiol Actions

Formamidopyrimidine-DNA glycosylase (Fpg) cleaves double-stranded DNA containing the damaged base 8-oxo-7,8-dihydroguanine. It functions as an N-glycosylase and apurinic/apyrimidinic lyase.

Fpg is a key enzyme in the DNA base excision repair pathway (BER). It catalyses the excision of a broad spectrum of modified purines. Fpg has both DNA glycosylase activity that removes the mutated base and AP-lyase activity that releases ribose leaving both 5′- and 3′-phosphorylated ends in the DNA. The zinc finger motif at its C-terminus is responsible for the DNA binding and AP-lyase activity. In addition, its N-terminal proline acts as a nucleophile to produce a Schiff base intermediate that is essential for enzyme action.

Fpg specifically acts on 3′- and 5′-phosphodiester bonds.

Unit Definition

One unit will cleave 50% of 0.5 pmol of double-stranded DNA oligomer substrate (8-oxoguanine−mutated) in 10 min at 25 °C.

Physical form

Solution in 50% glycerol containing 50 mM potassium HEPES, pH 7.5, 1 mM DTT, 1 mM EDTA, and 200 mM NaCl.