InterPro: IPR020084 NUDIX hydrolase, conserved site

MutT is a small bacterial protein (~12-15Kd) involved in the GO system [1] responsible for removing an oxidatively damaged form of guanine (8-hydroxy- guanine or 7,8-dihydro-8-oxoguanine) from DNA and the nucleotide pool. 8-oxo-dGTP is inserted opposite dA and dC residues of template DNA with near equal efficiency, leading to A.T to G.C transversions. MutT specifically degrades 8-oxo-dGTP to the monophosphate, with the concomitant release of pyrophosphate. A short conserved N-terminal region of mutT (designated the MutT domain) is also found in a variety of other prokaryotic, viral and eukaryotic proteins [2, 3, 4, 5].

The generic name `NUDIX hydrolases' (NUcleoside DIphosphate linked to some other moiety X) has been coined for this domain family [6]. The family can be divided into a number of subgroups, of which MutT anti- mutagenic activity represents only one type; most of the rest hydrolyse diverse nucleoside diphosphate derivatives (including ADP-ribose, GDP- mannose, TDP-glucose, NADH, UDP-sugars, dNTP and NTP).

This signature covers the core region of the NUDIX domain and contains four conserved glutamate residues [2]. The region spanned by this signature could be part of the active centre of a family of pyrophosphate-releasing NTPases.