Molecular cloning of cDNAs encoding insecticidal neurotoxic peptides from the spider Phoneutria nigriventer

From a Phoneutria nigriventer venom gland cDNA library several crones codin g for the insect specific neurotoxin Tx4(6-1) were isolated. cDNA analysis showed that the encoded protein contained three distinct segments, comprisi ng a signal sequence of 16 amino acids, followed by a glutamate-rich sequen ce of 18 amino acids and, finally, the coding region for the mature toxin. The deduced amino acid sequence for the mature polypeptide was identical to the protein sequence determined chemically. In addition, two new putative toxins called Pn4A and Pn4B were characterized and their predicted complete amino acid sequence revealed approximately 78% similarity to Tx4(6-1). (C) 2000 Elsevier Science Ltd. All rights reserved.