Isolation, purification, crystallization and preliminary X-ray analysis of beta 1-bungarotoxin from Bungarus caeruleus (Indian common krait).

Beta-Bungarotoxin is a heterodimeric neurotoxin consisting of a phospholipase A2 subunit linked by a disulfide bond to a K+ channel binding subunit, which is a member of of the Kunitz protease-inhibitor subfamily. Purified beta1-bungarotoxin was crystallized using microdialysis techniques. The rectangular-shaped crystals are orthorhombic, space group C2221, with unit-cell dimensions a = 80.7, b = 82.5, c = 56.9 A. The crystals have a calculated Vm of 2.35 A3 Da-1 for one molecule in the asymmetric unit. This corresponds to a solvent content of 48%. X-ray intensity data were collected to 2.6 A resolution. The data set is 97.4% complete.