Crystallization and preliminary X-ray diffraction studies of piratoxin III, a D-49 phospholipase A₂ from the venom of Bothrops pirajai

Piratoxin III (PrTX-III) is a phospholipase A₂ (PLA₂, E.C. 3.1.1.4, phosphatide sn-2 acylhydrolase) isolated from Bothrops pirajai. Crystals of PrTX-III were obtained using the vapour-diffusion technique and X-ray diffraction data have been collected to 2.7 Å resolution. The enzyme was crystallized in the space group C2 with unit-cell parameters a = 60.88, b = 100.75, c = 48.19 Å, β = 123.89°. A molecular-replacement solution of the structure has been found using bothropstoxin I from the venom of B. jararacussu as a search model.