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 w hich 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 pres ence of the detergent CYMAL-6 using the hanging-drop vapour-diffusion metho d with ammonium sulfate as precipitant. A set of diffraction data to 2.6 An gstrom resolution has been collected. Preliminary analysis of the diffracti on data indicated that the crystal belonged to space group R3, with unit-ce ll parameters a = b = 73.29, c = 68.90 Angstrom, alpha = beta = 90, gamma = 120 degrees. Assuming two molecules in the asymmetric unit, the estimated solvent content is 53.4%.