INTERACTION MODE OF N-DODECYLPHOSPHORYLCHOLINE, A SUBSTRATE-ANALOG, WITH BOVINE PANCREAS PHOSPHOLIPASE-A2 AS DETERMINED BY X-RAY CRYSTAL ANALYSIS

Three-dimensional structure of a bovine pancreas phospholipase A2 (PLA2) crystal complexed with n-dodecylphosphorylcholine (n-C12PC), a substrate-type inhibitor, has been determined by the X-ray diffraction method. The present conventional R value is 0.275 at 2.3Å resolution. The binding mode of n-C12PC to the PLA2 was clearly indicated, where the dodecyl chain was stably held by the hydrophobic contacts with the N-terminal rigion of PLA2 (Leu-2, Phe-5, and Ile-9), and the choline moiety was contacted with the hydrophobic space created by the side chains of Lys-53 and 56. The present result indicates that remarkable changes from the native PLA2 structure are caused at the N-terminal and middle (residues 60 to 70) regions by the binding of n-C12PC to the enzyme. © 1992.