Crystallization and preliminary X-ray study of biosynthetic alanine racemase from Pseudomonas aeruginosa PAO1.

Biosynthetic alanine racemase (AlrPA) from Pseudomonas aeruginosa PAO1 carrying a His6 tag was expressed in Escherichia coli BL21 (DE3) cells and purified by Ni(2+)-chelating affinity and anion-exchange chromatography for X-ray crystallographic analysis. Crystals were grown by the hanging-drop vapour-diffusion method at 289 K in a solution consisting of 4%(v/v) Tacsimate pH 5.0, 14%(w/v) polyethylene glycol 3350 with a protein concentration of 8 mg ml(-1). The crystal diffracted to 2.76 Å resolution and belonged to the orthorhombic space group P212121, with unit-cell parameters a = 74.12, b = 76.97, c = 154.80 Å, α = β = γ = 90°.