DHH phosphoesterase superfamily includes manganese-dependent inorganic pyrophosphatase (family II), Drosophila prune protein and bacterial RecJ exonuclease []. Typically, its members consist of two non-similar domains:domain 1 with parallel sheet of 6 strands and domain 2 with mixed sheet of 5 strands.
This domain is often found adjacent to the DHH domain (), and is called DHHA1 for DHH associated domain. DHHA1 is diagnostic of DHH subfamily 1 members []. This domain is also found in alanyl tRNA synthetase (e.g., ), suggesting that it may have an RNA binding function. The domain is about 60 residues long and contains a conserved GG motif.
This domain is called DHHA2 since it is often associated with the DHH domain () and is diagnostic of DHH subfamily 2 members []. The domain is about 120 residues long and contains a conserved DXK motif at its amino terminus. It is present in inorganic pyrophosphatases and in exopolyphosphatase of Saccharomyces cerevisiae.
This domain is called DHHA2 since it is often associated with the DHH domain and is diagnostic of DHH subfamily 2 members []. The domain is about 120 residues long and contains a conserved DXK motif at its amino terminus. It is present in inorganic pyrophosphatases and in exopolyphosphatase of Saccharomyces cerevisiae.
