Identification of continuous interaction sites in PLA(2)-based protein complexes by peptide arrays.
Crotoxin (CA.CB) is a beta-neurotoxin from Crotalus durissus terrificus snake venom that is responsible for main envenomation effects upon biting by this snake. It is a heterodimer of an acidic protein (CA) devoid of any biological activity per se and a basic, enzymatically active, PLA(2) counterpart (CB). Both lethal and enzymatic activities of crotoxin have been shown to be inhibited by CNF, a protein from the blood of C. d. terrificus snakes. CNF replaces CA in the CA.CB complex, forming a stable, non-toxic complex CNF.CB. The molecular sites involved in the tight interfacial protein-protein interactions in these PLA(2)-based complexes have not been clearly determined. To help address this question, we used the peptide arrays approach to map possible interfacial interaction sites in CA.CB and CNF.CB. Amino acid stretches putatively involved in these interactions were firstly identified in the primary structure of CB. Further analysis of the interfacial availability of these stretches in the presumed biologically active structure of CB, suggested two interaction main sites, located at the amino-terminus and beta-wing regions. Peptide segments at the carboxyl-terminus of CB were also suggested to play a secondary role in the binding of both CA and CNF.
Fortes-Dias
Consuelo Latorre
CL
Research and Development Center, Fundação Ezequiel Dias (FUNED), R. Conde Pereira Carneiro 80, 30510-010, Belo Horizonte, MG, Brazil. consuelo@funed.mg.gov.br
Santos
Roberta Márcia Marques dos
RM
Magro
Angelo José
AJ
Fontes
Marcos Roberto de Mattos
MR
Chávez-Olórtegui
Carlos
C
Granier
Claude
C
D000818:Animals; D003435:Crotalid Venoms / Q000737:chemistry*; D017839:Crotalus; D003439:Crotoxin / Q000378:metabolism*; D054501:Group II Phospholipases A2 / Q000378:metabolism*; D006801:Humans; D012911:Snakes / Q000378:metabolism*
D003435:Crotalid Venoms; D003439:Crotoxin; D054501:Group II Phospholipases A2; C516287:PLA2G2A protein, human