title: Eastern coral snake Micrurus fulvius venom toxicity in mice is mainly determined by neurotoxic phospholipases A2.
abstract: Here we show for the first time that the venom from an elapid (Micrurus fulvius) contains three finger toxin (3FTxs) peptides with low toxicity but high content of lethal phospholipases A2 (PLA2). The intravenous venom LD50 in mice was 0.3μg/g. Fractionation on a C18 column yielded 22 fractions; in terms of abundance, 58.3% of them were components of 13-14kDa and 24.9% were molecules of 6-7kDa. Two fractions with PLA2 activity represented 33.4% of the whole venom and were the most lethal fractions. Fractions with low molecular mass (<7000Da) partially and reversibly blocked the nicotinic acetylcholine receptor (nAChR), with the exception of one that blocked it completely. The fraction that blocked 100% contained two protein species whose dose-response was determined; the IC50s were 13±1 and 9.5±0.3nM. Despite the apparent effect on nAChR none of the low molecular mass fractions were lethal in mice, at concentrations of 1μg/g. From 2D-PAGE and LC-MS/MS, we identified fourteen species of PLA2, four protein species of C-type lectin, three zinc metalloproteinases, one phosphodiesterase and one 3FTx. The N-terminal amino acid sequence of fractions with biological interest was obtained.
  
  
  CONCLUSIONS
  In contrast with coral snake venoms from South America, M. fulvius has minor amounts of low molecular mass components, but high content of PLA2, which is responsible for the venom lethality of this species. The results reported here contribute to better understanding of envenomation development and to improve antivenom design and production. These findings break from the paradigm that neurotoxicity caused by Micrurus venoms is mainly attributable to 3FTx neurotoxins and encourage future studies on Micrurus evolution and venom specialization. This article is part of a Special Issue entitled Non-model organisms.
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Irene
authors.initials: I
authors.lastname: Vergara
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Martha
authors.initials: M
authors.lastname: Pedraza-Escalona
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Dayanira
authors.initials: D
authors.lastname: Paniagua
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Rita
authors.initials: R
authors.lastname: Restano-Cassulini
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Fernando
authors.initials: F
authors.lastname: Zamudio
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Cesar V F
authors.initials: CV
authors.lastname: Batista
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México.
authors.forename: Lourival D
authors.initials: LD
authors.lastname: Possani
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México. Electronic address: alagon@ibt.unam.mx.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Alagón
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004546:Elapid Venoms / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D017815:Elapidae / Q000378:metabolism*; D005260:Female; D008297:Male; D051379:Mice; D009498:Neurotoxins / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D018733:Nicotinic Antagonists / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D054467:Phospholipases A2 / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity; D011978:Receptors, Nicotinic / Q000378:metabolism
chemical_list: D004546:Elapid Venoms; D009498:Neurotoxins; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; C053972:micrurus venom; D054467:Phospholipases A2
keywords: Coral snake; Mass spectrometry; Micrurus fulvius; Neurotoxicity; Proteome