Crystallization and X‐ray diffraction studies of arginine kinase from the white Pacific shrimp Litopenaeus vannamei

Crystals of an unligated monomeric arginine kinase from the Pacific whiteleg shrimp Litopenaeus vannamei ( Lv AK) were successfully obtained using the microbatch method. Crystallization conditions and preliminary X‐ray diffraction analysis to 1.25 Å resolution are reported. Data were collected at 100 K on NSLS beamline X6A. The crystals belonged to space group P 2 1 2 1 2 1 , with unit‐cell parameters a = 56.5, b = 70.2, c = 81.7 Å. One monomer per asymmetric unit was found, with a Matthews coefficient ( V M ) of 2.05 Å 3  Da −1 and 40% solvent content. Initial phases were determined by molecular replacement using a homology model of Lv AK as the search model. Refinement was performed with PHENIX , with final R work and R free values of 0.15 and 0.19, respectively. Biological analysis of the structure is currently in progress.