STRUCTURAL STUDIES OF SNAKE INSULIN CRYSTALS——X-RAY CRYSTALLOGRAPHIC ANALYSIS OF SINGLE CRYSTALS

On the basis of the isolation and crystallization of snake （Zaocys dhumnades dhumna-des, Cantor） insulin, single crystals suitable for X-ray analysis were obtained in citrate buf-fer by micro-method of super-saturation. Resolution of diffraction by the crystal was over4 A, X-ray crystallographic analysis showed that the crystal was cubic with α=67.31 A, itsspace group was P432 and each asymmetric unit contained one molecule of snake insulin.The possible packing of hexamers and the orientation of monomers in the unit cell of snakeinsulin crystal were discussed.