Crystallization and preliminary X-ray analysis of XC1015, a histidine triad-like protein from Xanthomonas campestris

Histidine-triad (HIT) proteins are a superfamily of nucleotide hydrolases and transferases that contain a conserved HφHφHφφ motif (where φ is a hydrophobic amino acid) and are found in a variety of organisms. In addition to binding to a variety of nucleotides, other biological functions of the HIT superfamily proteins have been discovered and HIT malfunction has been implicated in several human diseases. Structural studies of HIT superfamily proteins are thus of particular interest. In this manuscript, the cloning, expression, crystallization and preliminary X-ray analysis of XC1015, a HIT protein present in the plant pathogen Xanthomonas campestris pathovar campestris, are reported. The XC1015 crystals diffracted to a resolution of 1.3 Å. They are tetragonal and belong to space group P4₃2₁2, with unit-cell parameters a = 40.52, b = 40.52, c = 126.89 Å.