Expression, crystallization and preliminary crystallographic analysis of PilZ_XAC1133 from Xanthomonas axonopodis pv. citri

Proteins containing PilZ domains are widespread in Gram-negative bacteria and have recently been shown to be involved in the control of biofilm formation, adherence, aggregation, virulence-factor production and motility. Furthermore, some PilZ domains have recently been shown to bind the second messenger bis(3′→5′)cyclic diGMP. Here, the cloning, expression, purification and crystallization of PilZ_XAC1133, a protein consisting of a single PilZ domain from Xanthomonas axonopodis pv. citri, is reported. The closest PilZ_XAC1133 homologues in Pseudomonas aeruginosa and Neisseria meningitidis control type IV pilus function. Recombinant PilZ_XAC1133 containing selenomethionine was crystallized in space group P6₁. The unit-cell parameters were a = 62.125, b = 62.125, c = 83.543 Å. These crystals diffracted to 1.85 Å resolution and a MAD data set was collected at a synchrotron source. The calculated Matthews coefficient suggested the presence of two PilZ_XAC1133 molecules in the asymmetric unit.