Crystallization and preliminary X-ray crystallographic analysis of the heterodimeric crotoxin complex and the isolated subunits crotapotin and phospholipase A2

摘要

Crotoxin, a potent neurotoxin from the venom of the South American rattlesnake Crotalus durissus terrificus, exists as a heterodimer formed between a phospholipase A2 and a catalytically inactive acidic phospholipase A2 analogue (crotapotin). Large single crystals of the crotoxin complex and of the isolated subunits have been obtained. The crotoxin complex crystal belongs to the orthorhombic space group P21212, with unit-cell parameters a = 38.2, b = 68.7, c = 84.2 Å, and diffracted to 1.75 Å resolution. The crystal of the phospholipase A2 domain belongs to the hexagonal space group P6122 (or its enantiomorph P6522), with unit-cell parameters a = b = 38.7, c = 286.7 Å, and diffracted to 2.6 Å resolution. The crotapotin crystal diffracted to 2.3 Å resolution; however, the highly diffuse diffraction pattern did not permit unambiguous assignment of the unit-cell parameters.