Sequence determination and characterization of a phospholipase A2 isozyme from Trimeresurus gramineus (green habu snake) venom.
In addition to phospholipase A2-I (PLA2-I) reported previously (ODA et al., 1991, Toxicon 29, 157), a new PLA2 named PLA2-II was isolated from Trimeresurus gramineus (green habu snake) venom, and its amino acid sequence was determined by sequencing the native protein and the peptides produced by enzymatic (Achromobacter protease I and clostripain) cleavages of the carboxamidomethylated derivative of the protein. The protein consisted of 122 amino acid residues and His-47, Asp-48, and Asp-98 which have been assumed to be essential for PLA2 activity were conserved. Its sequence similarity to PLA2-I was 79%, with 26 residual differences. In contrast to the unique presence of Phe-28 in PLA2-I, PLA2-II contains Tyr-28 as seen in most of other PLA2s. There was no significant difference between the dissociation constants of PLA2-I and PLA2-II for Ca2+. Secondary structure compositions of PLA2-II were similar to those of PLA2-I and Crotalus atrox PLA2. A striking difference was found between these isozymes in contractile activity of isolated smooth muscle preparation of guinea-pig ileum. PLA2-II was over ten times more potent than PLA2-I, although its lipolytic activity toward egg-yolk was even slightly weaker (73%) than that of PLA2-I. The difference in contractile activities of PLA2-I and PLA2-II could be assumed to be due to discriminative lipid recognition brought about by different amino acid residues at the 58th position (Asp for PLA2-I and Asn for PLA2-II).
Fukagawa
T
T
Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka, Japan.
Matsumoto
H
H
Shimohigashi
Y
Y
Ogawa
T
T
Oda
N
N
Chang
C C
CC
Ohno
M
M
D000421:Alcaligenes / Q000201:enzymology; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002848:Chromatography, DEAE-Cellulose; D003435:Crotalid Venoms / Q000201:enzymology* / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000032:analysis* / Q000494:pharmacology; D008297:Male; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010741:Phospholipases A / Q000032:analysis* / Q000494:pharmacology; D054467:Phospholipases A2
D003435:Crotalid Venoms; D007527:Isoenzymes; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium