Crystallization and preliminary X-ray analysis of a depressant insect toxin from the scorpion Buthus martensii Karsch.

Depressant insect toxins are a distinct group of scorpion neurotoxins for which no three-dimensional structures are yet available. A depressant insect toxin named BmK dITAP3 from the scorpion Buthus martensii Karsch (BmK) has been purified and crystallized. Single crystals of dITAP3 grew in the presence of the detergent CYMAL-6 using the hanging-drop vapour-diffusion method with ammonium sulfate as precipitant. A set of diffraction data to 2.6 A resolution has been collected. Preliminary analysis of the diffraction data indicated that the crystal belonged to space group R3, with unit-cell parameters a = b = 73.29, c = 68.90 A, alpha = beta = 90, gamma = 120 degrees. Assuming two molecules in the asymmetric unit, the estimated solvent content is 53.4%.