Summary
Agkicetin-C, a potent glycoprotein Ib antagonist from the venom of the Chinese pit
viper, Deinagkistrodon acutus, has been purified and characterized (5). It is a disulfide-linked
heterodimer containing subunits of 132 and of 123 amino acid residues. Herein, the
complete amino acid sequences were resolved by cloning and nucleotide sequencing of
the cDNAs. The sequences of its subunits are homologous to those of other snake venom
proteins of the C-type (Ca2+-dependent) lectin superfamily. A three-dimensional model of agkicetin-C was constructed
based on the crystal structure of habu coagulation factor IX/X-binding protein. By
careful alignment of all the related sequences available and comparing the 3D-model
of agkicetin-C with structures of other homologous proteins of different functions,
some variable residues of agkicetin-C were identified, which possibly are responsible
for the specificity of this distinct subtype of the C-type lectin-like venom proteins.
Keywords
Glycoprotein Ib - snake - modeling - C-lectin