Open AccessAmino acid sequence and immunological characterization with monoclonal antibodies of two toxins from the venom of the scorpion Centruroides noxius Hoffmann
Author(s) -
ZAMUDIO Fernando,
SAAVEDRA Rafael,
MARTIN Brian Michael,
GURROLABRIONES Georgina,
HÉRION Pascal,
POSSANI Lourival Domingos
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb16635.x
Subject(s) - venom , epitope , toxin , scorpion toxin , monoclonal antibody , scorpion venoms , chemistry , biology , peptide sequence , biochemistry , scorpion , antibody , immunology , gene
Two toxins, which we propose to call toxins 2 and 3, were purified to homogeneity from the venom of the scorpion Centruroides noxius Hoffmann. The full primary structures of both peptides (66 amino acid residues each) was determined. Sequence comparison indicates that the two new toxins display 79% identity and present a high similarity to previously characterized Centruroides toxins, the most similar toxins being Centruroides‐suffusus toxin 2 and Centruroides limpidus tecomanus toxin 1. Six monoclonal antibodies (mAb) directed against purified fraction II–9.2 (which contains toxins 2 and 3) were isolated in order to carry out the immunochemical characterization of these toxins. mAb BCF2, BCF3, BCF7 and BCF9 reacted only with toxin 2, whereas BCF1 and BCF8 reacted with both toxins 2 and 3 with the same affinity. Simultaneous binding of mAb pairs to the toxin and cross‐reactivity of the venoms of different scorpions with the mAb were examined. The results of these experiments showed that the mAb define four different epitopes (A–D). Epitope A (BCF8) is topographically unrelated to epitopes B (BCF2 and BCF7), C (BCF3) and D (BCF9) but the latter three appear to be more closely related or in close proximity to each other. Epitope A was found in all Centruroides venoms tested as well as on four different purified toxins of C. noxius , and thus seems to correspond to a highly conserved structure. Based on the cross‐reactivity of their venoms with the mAb, Centruroides species could be classified in the following order: Centruroides elegans, Centruroides suffusus suffusus = Centruroides infamatus infamatus, Centruroides limpidus tecomanus, Centruroides limpidus limpidus , and Centruroides limpidus acatlanensis , according to increasing immunochemical relatedness of their toxins to those of Centruroides noxius . All six mAb inhibited the binding of toxin 2 to rat brain synaptosomal membranes, but only mAb BCF2, which belongs to the IgG 2a subclass, displayed a clear neutralizing activity in vivo .