CRYSTAL-STRUCTURE DETERMINATION OF BASIC PHOSPHOLIPASE A(2) FROM VENOM OF AGKISTRODON HALYS PALLAS BY MOLECULAR REPLACEMENT METHOD

Basic phospholipase A(2) (BPLA(2)) from the venom of Agkistrodon halys pallas has a strong ability to hemolyze erythrocytes. The asymmetrica l unit of P2(1)2(1)2(1) crystal of BPLA(2) contains two molecules. Sel f-rotation function was used to study the orientation relationship of these two molecules. Cross-rotation and translation functions were the n used to determine the orientations and positions of the two molecule s in the unit cell. The model building and preliminary structure refin ement;were carried out. The result shows that the two molecules in the asymmetrical unit of orthorhombic crystal are related by a non-crysta llographic 2-fold symmetry axis.