Purification, crystallization and preliminary crystallographic analysis of the biotin–protein ligase from Pyrococcus horikoshii OT3

Biotin–protein ligase is an enzyme that catalyzes the ATP‐dependent biotinylation of a specific lysine residue in acetyl‐CoA carboxylase. The biotin–protein ligase from Pyrococcus horikoshii OT3 has been cloned, overexpressed and purified. Crystallization was performed by the microbatch method or the vapour‐diffusion method using PEG 2000 as a precipitant at 295 K. X‐ray diffraction data have been collected to 1.6 Å resolution from a native crystal and to 1.55 Å resolution from a selenomethionine‐derivative crystal for multiple anomalous dispersion phasing using synchrotron radiation at 100 K. The native crystal belongs to the monoclinic space group P 2 1 , with unit‐cell parameters a = 38.601, b = 78.264, c   =  70.147 Å, β = 101.48°. Assuming a homodimer per asymmetric unit gives a V M value of 2.14 Å 3  Da −1 and a solvent content of 42.5%. Cocrystals with biotin, ADP and biotinyl‐5′‐AMP were prepared and diffraction data sets were collected to 1.6, 1.6 and 1.45 Å resolution, respectively.