cDNA cloning and sequencing of phospholipase A(2) from the pyloric ceca ofthe starfish Asterina pectinifera

Three cDNA from the pyloric ceca of the starfish Asterina pectinifera, (nam ely, cDNA 1, 2, and 3), encoding phospholipase A(2) (PLA(2)), were isolated and sequenced. These cDNAs were composed of 415 bp with an open reading fr ame of 414 bp at nucleotide positions 1-414, which encodes 138 amino acids including N-terminal Met derived from the PCR primer. The amino acid sequen ce deduced from the cDNA 1 was completely consistent with the sequence dete rmined with the starfish PLA(2) protein, while those deduced from cDNA 2 an d cDNA 3 differed at one and twelve amino acid residual positions, respecti vely, from the sequence of the PLA(2) protein, suggesting the presence of m ultiple forms in the starfish PLA(2). All of the sequences deduced from cDN A 1, 2, and 3 required two amino acid deletions in pancreatic loop region, and sixteen insertions and three deletions in beta-wing region when aligned with the sequence of mammalian pancreatic PLA(2). In phylogenetic tree, th e starfish PLA(2) should be classified into an independent group, but hardl y to the established groups IA and IB. The characteristic structure in the pancreatic loop and beta-wing regions may account for the specific properti es of the starfish PLA(2), e.g. the higher activity and characteristic subs trate specificity compared with commercially available PLA(2) from porcine pancreas. (C) 2000 Elsevier Science Inc. All rights reserved.