title: First crotoxin-like phospholipase A(2) complex from a New World non-rattlesnake species: nigroviriditoxin, from the arboreal Neotropical snake Bothriechis nigroviridis.
abstract: Bothriechis nigroviridis is an arboreal Neotropical pitviper found in Costa Rica and Panamá. A previous proteomic profiling of its venom revealed the presence of proteins with homology to the A and B subunits of crotoxin/Mojave toxin, a heterodimeric phospholipase A2 (PLA2) complex only described in rattlesnake venoms (genera Crotalus and Sistrurus). The native crotoxin-like heterodimer, named nigroviriditoxin, and its A and B subunits were isolated in the present work, and the complete amino acid sequence of the B subunit was determined. The purified A and B components were demonstrated to form a complex when reconstituted under native conditions. Nigroviriditoxin presents features similar to crotoxin, albeit displaying lower toxicity: the A component decreases the PLA2 activity of the B component, and increases its lethal potency in mice. Also in similarity to crotoxin B, nigroviriditoxin B induces myonecrosis. Its 122 amino acid sequence presents 81% identity with crotoxin B. Accordingly, nigroviriditoxin B was cross-recognized by equine antibodies from a Crotalus durissus terrificus antivenom. Phylogenetic analysis shows that the novel PLA2 from B. nigroviridis venom is basal to the branch including all the homologous PLA2 enzymes described in rattlesnakes, and more distant from PLA2s from Bothriechis species. Nigroviriditoxin is the first heterodimeric PLA2 complex found in a non-rattlesnake, Neotropical viperid venom, which displays structural, functional, and immunochemical similarities to crotoxin. The present findings are compatible with the existence of the particular structural trait of crotoxin-like molecules in New World pitvipers before the split of the Meso-South American and the Nearctic clades.
authors.affiliation: Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica. Electronic address: bruno.lomonte@ucr.ac.cr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Lomonte
authors.affiliation: Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica.
authors.forename: Diana
authors.initials: D
authors.lastname: Mora-Obando
authors.affiliation: Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica.
authors.forename: Julián
authors.initials: J
authors.lastname: Fernández
authors.affiliation: Instituto de Biomedicina de Valencia, CSIC, Jaume Roig 11, 46010 Valencia, Spain.
authors.forename: Libia
authors.initials: L
authors.lastname: Sanz
authors.affiliation: Instituto de Biomedicina de Valencia, CSIC, Jaume Roig 11, 46010 Valencia, Spain.
authors.forename: Davinia
authors.initials: D
authors.lastname: Pla
authors.affiliation: Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica.
authors.forename: José María
authors.initials: JM
authors.lastname: Gutiérrez
authors.affiliation: Instituto de Biomedicina de Valencia, CSIC, Jaume Roig 11, 46010 Valencia, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Calvete
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003364:Costa Rica; D003429:Cross Reactions; D003439:Crotoxin / Q000031:analogs & derivatives / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D016013:Likelihood Functions; D046911:Macromolecular Substances / Q000737:chemistry* / Q000378:metabolism; D013058:Mass Spectrometry; D051379:Mice; D008957:Models, Genetic; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010176:Panama; D054467:Phospholipases A2 / Q000378:metabolism*; D010802:Phylogeny; D021122:Protein Subunits / Q000235:genetics; D017422:Sequence Analysis, DNA; D017819:Viperidae
chemical_list: D046911:Macromolecular Substances; D021122:Protein Subunits; C000600589:nigroviriditoxin, Bothriechis nigroviridis; D003439:Crotoxin; D054467:Phospholipases A2
keywords: Bothriechis nigroviridis; Crotoxin; Phospholipase A(2); Snake venom; Viperidae