InterPro domain: IPR002637

This family contains the Saccharomyces cerevisiae (Baker's yeast) HAM1 protein P47119 and other hypothetical archaeal, bacterial and Caenorhabditis elegans proteins. S. cerevisiae HAM1 was originally identified as a gene that protects against the mutagenic effects of the base analogue 6-N-hydroxylaminopurine (HAP) which can be a natural product of monooxygenase activity on adenine [ 1 , 2 ]. Subsequent studies demonstrated that HAM1 detoxifies abnormal pyrimidine as well as purine nucleotides [ 3 ].

Similarly, a Ham1-related protein from Methanococcus jannaschii is a novel NTPase that has been shown to hydrolyze nonstandard nucleotides such as XTP to XMP and ITP to IMP, but not the standard nucleotides, in the presence of Mg or Mn ions. The enzyme exists as a homodimer [ 4 ].

1. HAM1, the gene controlling 6-N-hydroxylaminopurine sensitivity and mutagenesis in the yeast Saccharomyces cerevisiae. Yeast 12, 17-29
2. Overexpression of the yeast HAM1 gene prevents 6-N-hydroxylaminopurine mutagenesis in Escherichia coli. Acta Biochim. Pol. 45, 645-52
3. Overexpression of HAM1 gene detoxifies 5-bromodeoxyuridine in the yeast Saccharomyces cerevisiae. Curr. Genet. 52, 203-11
4. Structure-based identification of a novel NTPase from Methanococcus jannaschii. Nat. Struct. Biol. 6, 691-6