Protein expression, purification, crystallization and crystallographic studies of BPSL0741 from Burkholderia pseudomallei

Abstract

Burkholderia pseudomallei is the causative agent of the lethal disease melioidosis. This bacterium infects animals and humans and is increasingly resistant to multiple antibiotics. Recently, genes associated with survival of the bacterium in the infected host have been identified. One of these genes, bpsl0741, is annotated as a hypothetical protein of 185 amino acids. Here, recombinant BPSL0741 (rBPSL0741) protein was expressed, purified, verified by mass spectrometry, crystallized and analyzed by X-ray diffraction. rBPSL0741 was crystallized by vapor diffusion using a reservoir solution consisting of 0.2 M ammonium acetate, 0.1 M sodium acetate trihydrate pH 4.6, 30% PEG 4000. The crystals diffracted to 2.1 Å resolution using an in-house X-ray diffractometer and belonged to an orthorhombic space group, with unit-cell parameters a = 62.92, b = 64.57, c = 89.16 Å. The Matthews coefficient (V_M) was calculated to be 2.18 ų Da⁻¹, suggesting the presence of two molecules per asymmetric unit and an estimated solvent content of 43.5%. The crystal was deemed to be suitable for further structural studies, which are currently ongoing.