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 P 1, 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.