Immunochemical characterization and role in toxic activities of region 115-129 of myotoxin II, a Lys49 phospholipase A2 from Bothrops asper snake venom
artículo original
Fecha
1998-10Autor
Calderón Fuentes, Leonel
Lomonte, Bruno
Metadatos
Mostrar el registro completo del ítemResumen
The region 115–129 of myotoxin II, a catalytically inactive
Lys49 phospholipase A2, was previously shown to
constitute a heparin-binding site and to be involved in
its cytolytic action in vitro. An immunochemical approach
was utilized to further explore the role of this
region in the toxic activities of myotoxin II. By using a
carrier-linked 13-mer synthetic peptide as immunogen,
rabbit polyclonal antibodies against region 115–
129 were obtained. These antibodies were able to bind
to the native protein and to inhibit its myotoxic and
cytolytic effects in preincubation-type neutralization
experiments. Antibodies to peptide 115–129 formed
precipitating macromolecular complexes in gel immunodiffusion,
demonstrating the oligomeric state of
myotoxin II not only in its crystalline structure
(dimeric), but also in solution. Analyses of the antibody
response to carrier-linked peptide 115–129 and
native myotoxin II suggest that region 115–129, although
potentially immunogenic, is not an immunodominant
B-cell epitope of this protein, failing to elicit
significant antibody responses in animals immunized
with the native toxin. Antibodies to peptide 115–129
cross-reacted with 15 purified class II myotoxic phospholipases
A2 found in snake venoms of the genera
Bothrops, Agkistrodon, Trimeresurus, and Vipera, but
not with the recombinant human class II phospholipase
A2, for which no toxic actions have been described.
Myotoxic phospholipases of the class I (notexin)
and class III (bee venom) groups were not recognized
by antibodies to p115–129. These results
demonstrate that the overall antigenic structure of
region 115–129 is conserved among class II myotoxic
phospholipases A2, despite differences in their corresponding
amino acid sequences. Based on the accumulated
experimental evidence, a model of the myotoxic
region of myotoxin II, and possibly of related class II
Lys49 phospholipase A2 myotoxins, is proposed.
External link to the item
10.1006/abbi.1998.0853Colecciones
- Microbiología [1171]