A putative polyketide-synthesis protein XC5357 from Xanthomonas campestris: Heterologous expression, crystallization and preliminary X-ray analysis

Xanthomonas campestris pv. campestris (Xcc) is a Gram-negative yellow-pigmented bacterium and is the causative agent of black rot, one of the major worldwide diseases of cruciferous crops. It also synthesizes a variety of polyketide metabolites that lead to important antibiotics. XC5357 is a putative 12.2 kDa protein of unknown structure from Xcc that is likely to be essential for polyketide synthesis. It was overexpressed in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. The crystals belong to the triclinic space group P1, with unit-cell parameters a = 43.7, b = 43.7, c = 46.5 Å, α = 65.0, β = 64.9, γ = 73.4°, and diffracted to a resolution of 1.85 Å.