Cloning, crystallization and preliminary X-ray studies of XC2981 from Xanthomonas campestris, a putative CutA1 protein involved in copper-ion homeostasis.

Divalent metal ions play key roles in all living organisms, serving as cofactors for many proteins involved in a variety of electron-transfer activities. However, copper ions are highly toxic when an excessive amount is accumulated in a cell. CutA1 is a protein found in all kingdoms of life that is believed to participate in copper-ion tolerance in Escherichia coli, although its specific function remains unknown. Several crystal structures of multimeric CutA1 with different rotation angles and degrees of interaction between trimer interfaces have been reported. Here, the cloning, expression, crystallization and preliminary X-ray analysis of XC2981, a possible CutA1 protein present in the plant pathogen Xanthomonas campestris, are reported. The XC2981 crystals diffracted to a resolution of 2.6 A. They are cubic and belong to space group I23, with unit-cell parameters a = b = c = 130.73 A.