Analysis of the cDNA for phospholipase A2 from honeybee venom glands

Abstract

A cDNA expression library was constructed from worker bee venom glands and screened with an antibody against phospho lipase A2. The nucleotide sequence of a positive clone with the largest insert showed an open reading frame that codes for part of the signal peptide, the pro-region an the entire mature enzyme of the bee venom phospholipase A2 precursor. This sequence differs in the central region from the one determined by Shipolini et al. [FEBS Lett. 17, 39-40 (1971)] in showing, among other exchanges, two additional cysteines. The revised sequence of bee venom phospholipase is similar to the pancreatic enzyme in the spacing of cysteines and the presence of several amino acids known to be part of the active site or the Ca2+-binding region in identical positions. Moreover, these parts of the bee protein can be fitted into the three-dimensional structure determined for the bovine pancreatic phospholipase A2 [Dijkstra et al.(1981) Nature 289, 604-606]. Contrary to earlier suggestions, we therefore conclude that the bee venom enzyme showed some homology to phospholipases from mammalian pancreas and snake venoms.