Purification, crystallization and preliminary X-ray crystallographic analysis of a phospholipase A₂ from Daboia russelli pulchella

Phospholipases are esterolytic enzymes which hydrolyze glycerophospholipids. The pharmacological efficiency of phospho­lipase A₂ (PLA₂) enzymes is reflected by their specificity towards a tissue or organ. The Russell's viper has been classified into two classes. Class 1 contains Viper russelli russelli, Viper russelli siamensis and Viper russelli formosensis, whereas class 2 contains Daboia russelli pulchella. The sequence identity between the PLA₂s from these two classes is 47%. The novel PLA₂ from Daboia russelli pulchella has been crystallized using the hanging-drop vapour-diffusion method with ammonium sulfate as precipitating agent. Crystals belong to the orthorhombic space group C222₁ with unit-cell parameters a = 77.01, b = 92.29, c = 76.90 Å and two molecules in the asymmetric unit. These crystals diffract to about 2.49 Å resolution using a rotating-anode source.