Island specific expression of a novel [Lys49]phospholipase A2 (BPIII) in Protobothrops flavoviridis venom in Amami-Oshima, Japan

In search of the transcripts expressed in Protobothrops flavoviridis venom gland, 466 expressed sequence tags (ESTs) were generated from the venom gland cDNA library of P. flavoviridis in Amami-Oshima, Japan. The sequencing of randomly selected cDNA clones followed by identification in similarity search against existing databases led to the finding of a novel lysine-49-phospholipase A(2) ([Lys(49)]PLA(2)) clone. It coded for one amino acid-substituted BPII homologue or two amino acids-substituted BPI homologue in which BPII and BPI are [Lys(49)]PLA(2)s contained in Amami-Oshima and Tokunoshima P. flavoviridis venoms. This isozyme, named BPIII, was isolated from Amami-Oshima P flavoviridis venom. BPIII gave a specific [M + 2H](2+) peak of m/z 736.3 on mass spectrometry (MS) analysis after S-carboxamidomethylation and trypsin digestion when compared with BPII. It became evident from MS analysis after S-carboxamidomethylation and trypsin digestion of the mixed protein peaks ranging from BPI to BPII obtained by fractionation on a carboxymethyl cellulose column of Amami-Oshima and Tokunoshima P flavoviridis venoms that BPIII protein is contained in Amami-Oshima P. flavoviridis venom but not in Tokunoshima R flavoviridis venom. It is for the first time that a protein present in Amami-Oshima P. flavoviridis venom is not found in Tokunoshima P. flavoviridis venom. (C) 2009 Elsevier Ltd. All rights reserved.