title: Amino acid sequence and biological characterization of BlatPLA₂, a non-toxic acidic phospholipase A₂ from the venom of the arboreal snake Bothriechis lateralis from Costa Rica.
abstract: Bothriechis is considered a monophyletic, basal genus of arboreal Neotropical pitvipers distributed across Middle America. The four species found in Costa Rica (B. lateralis, B. schlegeli, B. nigroviridis, B. supraciliaris) differ in their venom proteomic profiles, suggesting that different Bothriechis taxa have evolved diverse trophic strategies. In this study, we isolated a phospholipase A₂ (PLA₂) from B. lateralis venom, aiming at increasing our knowledge on the structural and functional characteristics of group II acidic PLA₂s, whose toxic actions are generally more restricted than those displayed by basic PLA₂s. The new acidic enzyme, BlatPLA₂, occurs as a monomer of 13,917 Da, in contrast to many basic group II PLA₂s which associate into dimers and often display myotoxicity and/or neurotoxicity. Its amino acid sequence of 122 residues predicts an isoelectric point of 4.7, and displays significant differences with previously characterized acidic PLA₂s, with which it shows a maximum sequence identity of 78%. BlatPLA₂ is catalytically active but appears to be devoid of major toxic activities, lacking intravenous or intracerebroventricular lethality, myotoxicity, in vitro anticoagulant activity, and platelet aggregation or inhibition effects. Phylogenetic relationships with similar group II enzymes suggest that BlatPLA₂ may represent a basal sequence to other acidic PLA₂s. Due to the metabolic cost of venom protein synthesis, the presence of a relatively abundant (9%) but non-toxic component is somewhat puzzling. Nevertheless, we hypothesize that BlatPLA₂ could have a role in the pre-digestion of prey, possibly having retained characteristics of ancestral PLA₂s without evolving towards potent toxicity.
authors.affiliation: Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica.
authors.forename: Marco
authors.initials: M
authors.lastname: Van der Laat
authors.forename: Julián
authors.initials: J
authors.lastname: Fernández
authors.forename: Jordi
authors.initials: J
authors.lastname: Durban
authors.forename: Eva
authors.initials: E
authors.lastname: Villalobos
authors.forename: Erika
authors.initials: E
authors.lastname: Camacho
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Calvete
authors.forename: Bruno
authors.initials: B
authors.lastname: Lomonte
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D019295:Computational Biology; D003364:Costa Rica; D003429:Cross Reactions / Q000187:drug effects; D003435:Crotalid Venoms / Q000201:enzymology* / Q000235:genetics; D004487:Edema / Q000139:chemically induced; D007526:Isoelectric Point; D051379:Mice; D008969:Molecular Sequence Data; D054467:Phospholipases A2 / Q000737:chemistry / Q000235:genetics* / Q000633:toxicity; D010802:Phylogeny; D010974:Platelet Aggregation / Q000187:drug effects; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018675:Toxicity Tests; D017819:Viperidae / Q000235:genetics*
chemical_list: D003435:Crotalid Venoms; D054467:Phospholipases A2
keywords: Arboreal snake; Bothriechis lateralis; Phospholipase A(2); Snake venom; Viperidae