Cloning of cDNAs encoding C-type lectins from Elapidae snakes Bungarus fasciatus and Bungarus multicinctus.

A number of C-type lectins with various biological activities have been purified and characterized from Viperidae snake venoms. In contrast, only a few reports could be found in literature concerning the C-type lectins in Elapidae snake venoms. Based on the published cDNA sequences of C-type lectins from Viperidae snake venoms, oligonucleotide primers were designed and used to screen the cDNA libraries made from the venom glands of Bungarus fasciatus and Bungarus multicinctus. This allowed the cloning of three full length cDNAs encoding C-type lectins. The encoded proteins, named BFL-1, BFL-2 and BML, exhibit high degrees of sequence identities with Viperidae snake venom saccharide-binding lectins (around 60% with Trimeresurus stejnegeri venom lectin, Crotalus atrox venom lectin and Agkistrodon piscivorus venom lectin). They show much less identities with other venom C-type lectin-like proteins (around 30% with the platelet glycoprotein Ib-binding protein from Agkistrodon blomhoffi venom and the factor IX/X-binding protein from Trimeresurus flavoviridis venom). The cDNAs revealed that the precursors contain potential signal peptides characterized by a hydrophobic core. To our knowledge, these are the first cDNA cloning of group VII C-type lectins (Drickamer K. 1993. Prog. Nucleic Acid Res. Mol. Biol. 45, 207-232) from Elapidae snake venom glands.