Cloning and characterization of an alpha-neurotoxin-type protein specific for the coral snake Micrurus corallinus

During the cloning of abundant cDNAs expressed in the Micrurus corallinus c oral snake venom gland, we cloned an a-neurotoxin homologue cDNA (nxh1). Tw o others isoforms mere also cloned (nxh3 and nxh7, respectively). The nxh1 cDNA codes for a potential coral snake toxin with a signal peptide of 21 am ino acids plus a predicted mature peptide with 57 amino acids. The deduced protein is highly similar to known toxic three-finger a-neurotoxins, with f our deduced S-S bridges at the same conserved positions. This is the first cDNA coding for a three-finger related protein described so far for coral s nakes. However, the predicted protein does not possess some of the importan t amino acids for the nicotinic acetylcholine receptor interaction, This pr otein was expressed in Escherichia coli as a His-tagged protein that allowe d the rapid purification of the recombinant protein. This protein was used to generate antibodies which recognized the recombinant protein in Western blot and also a single band present in the M. corallinus venom, but not in the venom of 10 other Micrurus species. (C) 2000 Academic Press.