Primary structures and partial toxicological characterization of two phospholipases A2from Micrurus mipartitus and Micrurus dumerilii coral snake venoms.
Snake venom phospholipases A2(PLA2) share high sequence identities and a conserved structural scaffold, but show important functional differences. Only a few PLA2s have been purified and characterized from coral snake (Micrurus spp.) venoms, and their role in envenomation remains largely unknown. In this report, we describe the isolation, sequencing and partial functional characterization of two Micrurus PLA2s: MmipPLA2from Micrurus mipartitus and MdumPLA2from Micrurus dumerilii, two species of clinical importance in Colombia. MmipPLA2consisted of 119 amino acid residues with a predicted pI of 8.4, whereas MdumPLA2consisted of 117 residues with a pI of 5.6. Both PLA2s showed the conserved 'group I' cysteine pattern and were enzymatically active, although MdumPLA2had higher activity. The two enzymes differed notably in their toxicity, with MmipPLA2being highly lethal to mice and mildly myotoxic, whereas MdumPLA2was not lethal (up to 3 μg/g body weight) but strongly myotoxic. MdumPLA2displayed higher anticoagulant activity than MmipPLA2in vitro and caused more sustained edema in the mouse footpad assay. Neither of these enzymes was cytolytic to cultured skeletal muscle C2C12 myotubes. Based on their structural differences, the two enzymes were placed in separate lineages in a partial phylogeny of Micrurus venom PLA2s and this classification agreed with their divergent biological activities. Overall, these findings highlight the structural and functional diversity of Micrurus venom PLA2s.
Programa de Ofidismo y Escorpionismo, Universidad de Antioquia, Medellín, Colombia. Electronic address: ofidpa@gmail.com.
Paola
P
Rey-Suárez
Programa de Ofidismo y Escorpionismo, Universidad de Antioquia, Medellín, Colombia; Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia.
Vitelbina
V
Núñez
Departamento de Ciencias, Universidad Iberoamericana de Ciencias y Tecnología, Chile; Centro de Investigación en Recursos Naturales y Sustentabilidad, Universidad Bernardo O'Higgins, Fábrica 1990, Segundo Piso, Santiago, Chile.
Mónica
M
Saldarriaga-Córdoba
Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica.
Bruno
B
Lomonte
D000595:Amino Acid Sequence; D000818:Animals; D000925:Anticoagulants / Q000633:toxicity; D001777:Blood Coagulation / Q000187:drug effects; D004487:Edema / Q000139:chemically induced / Q000473:pathology*; D004546:Elapid Venoms / Q000737:chemistry / Q000201:enzymology*; D017815:Elapidae / Q000145:classification / Q000378:metabolism*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000473:pathology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology; D054467:Phospholipases A2 / Q000737:chemistry* / Q000633:toxicity*; D010802:Phylogeny; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D000925:Anticoagulants; D004546:Elapid Venoms; D054467:Phospholipases A2
Coral snake; Elapid toxins; Micrurus dumerilii; Micrurus mipartitus; Phospholipase A(2); Venom