Biochemical Journal

Research communication

Identification of the Mg2+-binding site in the P-type ATPase and phosphatase members of the HAD (haloacid dehalogenase) superfamily by structural similarity to the response regulator protein CheY

Ivo S. RIDDER, Bauke W. DIJKSTRA

Abstract

The large HAD (haloacid dehalogenase) superfamily of hydrolases comprises P-type ATPases, phosphatases, epoxide hydrolases and l-2-haloacid dehalogenases. A comparison of the three-dimensional structure of l-2-haloacid dehalogenase with that of the response regulator protein CheY allowed the assignment of a conserved pair of aspartate residues as the Mg2+-binding site in the P-type ATPase and phosphatase members of the superfamily. From the resulting model of the active site, a conserved serine/threonine residue is suggested to be involved in phosphate binding, and a mechanism comprising a phosphoaspartate intermediate is postulated.

  • active site
  • l-2-haloacid dehalogenase
  • catalytic mechanism