Dendrotoxins (Dendroaspis species)

Abstract

Abstract Dendrotoxins block certain voltage-dependent K+ channels in neurones (Harvey and Anderson 1991). They are isolated from venom of three species of African mamba snakes: the Eastern green mamba (Dendroaspis angusticeps), the Western green mamba (D. viridis), and the black mamba (D. polylepis) (Strydom 1973a; Harvey and Karlsson 1980). The dendrotoxins are small basic proteins of 57–60 residues in a single polypeptide chain crosslinked by three disulfide bonds (Fig. 1). Six natural variants have been sequenced: two isoforms of α-dendrotoxin and δ-dendrotoxin from D. angusticeps, toxin I and toxin K from D. polylepis, and Dv-14 from viridis (Strydom 1973b; Joubert and Taljaard 1980;Mehraban et al. 1986). Two related toxins, γ- and y-dendrotoxin, from D. angusticeps have been partially sequenced (Benishin et al. 1988).