InterPro domain: IPR015797

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 superfamily [ 6 ]. The superfamily 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).

1. The GO system protects organisms from the mutagenic effect of the spontaneous lesion 8-hydroxyguanine (7,8-dihydro-8-oxoguanine). J. Bacteriol. 174, 6321-5
2. A highly conserved sequence motif defining the family of MutT-related proteins from eubacteria, eukaryotes and viruses. Nucleic Acids Res. 21, 4847
3. Characterization of the mutX gene of Streptococcus pneumoniae as a homologue of Escherichia coli mutT, and tentative definition of a catalytic domain of the dGTP pyrophosphohydrolases. Mol. Microbiol. 11, 323-30
4. Cloning and expression of cDNA for a human enzyme that hydrolyzes 8-oxo-dGTP, a mutagenic substrate for DNA synthesis. J. Biol. Chem. 268, 23524-30
5. The MutT motif family of nucleotide phosphohydrolases in man and human pathogens (review). Int. J. Mol. Med. 4, 79-89
6. The MutT proteins or "Nudix" hydrolases, a family of versatile, widely distributed, "housecleaning" enzymes. J. Biol. Chem. 271, 25059-62