Purification, partial characterization, crystallization and preliminary X-ray diffraction of two cysteine-rich secretory proteins from Naja atra and Trimeresurus stejnegeri venoms

Cysteine-rich secretory proteins (CRISPs) are widely distributed in mammals and snake venoms. They possess apparent homology but varying functions. The structure of CRISPs has remained elusive. Two novel members of the family, natrin and stecrisp, have been purified from Naja atra and Trimeresurus stejnegeri venoms, respectively. Their crystals diffract X-rays to resolution limits of 2.1 and 1.6 Å, repectively, and belong to the orthorhombic system with different space groups, unit-cell parameters and numbers of molecules per asymmetric unit. Their structures will contribute a structural basis for further functional studies of this family.