InterPro domain: IPR006549

This group of proteins is a part of the haloacid dehalogenase (HAD) superfamily of aspartate-nucleophile hydrolases. The Class III subfamilies are characterised by the lack of any domains located either between the first and second conserved catalytic motifs (as in the Class I subfamilies) or between the second and third conserved catalytic motifs (as in the Class II subfamilies) of the superfamily domain [ 1 , 2 ]. The IIIA subfamily contains five major clades: histidinol-phosphatase [ 3 ], histidinol-phosphatase-related protein, DNA 3-phosphatase and sequences related to YqeG and YrbI.

In the case of histidinol phosphatase and PNK-3'-phosphatase, this entry represents a domain of a bifunctional system. In the histidinol phosphatase HisB, a C-terminal domain is an imidazoleglycerol-phosphate dehydratase which catalyses a related step in histidine biosynthesis [ 4 ]. In PNK-3'-phosphatase, N- and C-terminal domains constitute the polynucleotide kinase and DNA-binding components of the enzyme.

1. Computer analysis of bacterial haloacid dehalogenases defines a large superfamily of hydrolases with diverse specificity. Application of an iterative approach to database search. J. Mol. Biol. 244, 125-32
2. MDP-1 is a new and distinct member of the haloacid dehalogenase family of aspartate-dependent phosphohydrolases. Biochemistry 40, 12704-11
3. Gene structure in the histidine operon of Escherichia coli. Identification and nucleotide sequence of the hisB gene. Mol. Gen. Genet. 202, 42-7