title: Differential expression and geographic variation of the venom phospholipases A2 of Calloselasma rhodostoma and Trimeresurus mucrosquamatus.
abstract: To investigate the geographic variations in venoms of two medically important pitvipers, we have purified and characterized the phospholipases A2 (PLA2s) from the pooled venoms of Calloselasma rhodostoma from Malaysia, Thailand, Indonesia, and Vietnam, as well as the individual venom of Trimeresurus mucrosquamatus collected from both North and South Taiwan. Enzymatic and pharmacological activities of the purified PLA2s were also investigated. The complete amino acid sequences of the purified PLA2s were determined by sequencing the corresponding cDNAs from the venom gland and shown to be consistent with their molecular weight data and the N-terminal sequences. All the geographic venom samples of C. rhodostoma contain a major noncatalytic basic PLA2-homolog and two or three acidic PLA2s in different proportions. These acidic PLA2s contain Glu6-substitutions and show distinct inhibiting specificities toward the platelets from human and rabbit. We also found that the T. mucrosquamatus venoms from North Taiwan but not those from South Taiwan contain an Arg6-PLA2 designated as TmPL-III. Its amino acid sequence is reported for the first time. This enzyme is structurally almost identical to the low- or nonexpressed Arg6-PLA2 from C. rhodostoma venom gland, and thus appears to be a regressing venom component in both of the Asian pitvipers.
authors.affiliation: Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China. bc201@gate.sinica.edu.tw
authors.forename: I H
authors.initials: IH
authors.lastname: Tsai
authors.forename: Y H
authors.initials: YH
authors.lastname: Chen
authors.forename: Y M
authors.initials: YM
authors.lastname: Wang
authors.forename: M Y
authors.initials: MY
authors.lastname: Liau
authors.forename: P J
authors.initials: PJ
authors.lastname: Lu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D003435:Crotalid Venoms / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D014644:Genetic Variation; D054501:Group II Phospholipases A2; D006801:Humans; D007214:Indonesia; D008296:Malaysia; D008969:Molecular Sequence Data; D010741:Phospholipases A / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D054467:Phospholipases A2; D010974:Platelet Aggregation / Q000187:drug effects; D011817:Rabbits; D030162:Reptilian Proteins; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D013624:Taiwan; D013785:Thailand; D014744:Vietnam
chemical_list: D003435:Crotalid Venoms; D030162:Reptilian Proteins; C029748:Trimeresurus venoms; D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2; C426832:TmPL-III protein, Trimeresurus mucrosquamatus