title: Biochemical and functional studies of ColTx-I, a new myotoxic phospholipase A2 isolated from Crotalus oreganus lutosus (Great Basin rattlesnake) snake venom.
abstract: Commonly, phospholipases A2 (PLA2s) play key roles in the pathogenesis of the local tissue damage characteristic of crotaline and viperine snake envenomations. Crotalus oreganus lutosus snake venom has not been extensively studied; therefore, the characterization of its components represents a valuable biotechnological tool for studying pathophysiological processes of envenoming and for gaining a deeper understanding of its biological effects. In this study, for the first time, a basic PLA2 myotoxin, ColTx-I, was purified from C. o. lutosus through two chromatographic steps. ColTx-I is monomeric with calculated molecular mass weight (Mw) of 14,145 Da and a primary structure closely related to basic PLA2s from viperid venoms. The pure enzyme has a specific activity of 15.87 ± 0.65 nmol/min/mg at optimal conditions (pH 8.0 and 37 °C). ColTx-I activity was found to be dependent on Ca(2+), as its substitution by other ionic species as well as the addition of chelating agents significantly reduced its phospholipase activity. In vivo, ColTx-I triggered dose-dependent inflammatory responses, measured using the paw edema model, with an increase in IL-6 levels, systemic and local myotoxicity, characterized by elevated plasma creatine kinase activity. ColTx-I induced a complex series of degenerative events associated with edema, inflammatory infiltrate and skeletal muscle necrosis. These biochemical and functional results suggest that ColTx-I, a myotoxic and inflammatory mediator, plays a relevant role in C. o. lutosus envenomation. Thus, detailed studies on its mechanism of action, such as evaluating the synergism between ColTx-I and other venom components may reveal targets for the development of more specific and effective therapies.
authors.affiliation: Department of Biochemistry and Tissue Biology, Institute of Biology, Campinas State University (UNICAMP), Campinas, SP, Brazil; IKIAM - Universidad Regional Amazónica, Tena, Napo, Ecuador; International Network of Ecuadorian Snakes Venoms Studies (RIEVSE), Ecuador.
authors.forename: J R
authors.initials: JR
authors.lastname: Almeida
authors.affiliation: Department of Biochemistry and Tissue Biology, Institute of Biology, Campinas State University (UNICAMP), Campinas, SP, Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: Resende
authors.affiliation: CCO, Universidade Federal de São João del Rei, Divinópolis, MG, Brazil.
authors.forename: A G
authors.initials: AG
authors.lastname: Silva
authors.affiliation: CCO, Universidade Federal de São João del Rei, Divinópolis, MG, Brazil.
authors.forename: R I M A
authors.initials: RI
authors.lastname: Ribeiro
authors.affiliation: Oswaldo Cruz Fundation (FIOCRUZ), CEBio, Fiocruz Rondônia and Federal University of Rondônia, Porto Velho, RO, Brazil; International Network of Ecuadorian Snakes Venoms Studies (RIEVSE), Ecuador.
authors.forename: R G
authors.initials: RG
authors.lastname: Stábeli
authors.affiliation: Oswaldo Cruz Fundation (FIOCRUZ), CEBio, Fiocruz Rondônia and Federal University of Rondônia, Porto Velho, RO, Brazil; International Network of Ecuadorian Snakes Venoms Studies (RIEVSE), Ecuador.
authors.forename: A M
authors.initials: AM
authors.lastname: Soares
authors.affiliation: Oswaldo Cruz Fundation (FIOCRUZ), CEBio, Fiocruz Rondônia and Federal University of Rondônia, Porto Velho, RO, Brazil; International Network of Ecuadorian Snakes Venoms Studies (RIEVSE), Ecuador.
authors.forename: L A
authors.initials: LA
authors.lastname: Calderon
authors.affiliation: Department of Biochemistry and Tissue Biology, Institute of Biology, Campinas State University (UNICAMP), Campinas, SP, Brazil.
authors.forename: S
authors.initials: S
authors.lastname: Marangoni
authors.affiliation: IKIAM - Universidad Regional Amazónica, Tena, Napo, Ecuador; International Network of Ecuadorian Snakes Venoms Studies (RIEVSE), Ecuador. Electronic address: biomol2@hotmail.com.
authors.forename: S L
authors.initials: SL
authors.lastname: Da Silva
mesh_terms: D000818:Animals; D003435:Crotalid Venoms / Q000737:chemistry*; D017839:Crotalus; D051379:Mice; D054467:Phospholipases A2 / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D010802:Phylogeny; D030162:Reptilian Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein
chemical_list: D003435:Crotalid Venoms; D030162:Reptilian Proteins; D054467:Phospholipases A2
keywords: Biological activities; Crotalus oreganus lutosus; Myotoxin; Phospholipase A(2); Snake venom