Molecular cloning of a cDNA encoding a nerve growth factor precursor from the krait, Bungarus multicinctus.

NGFs have been isolated from the venom of many snakes. Here we report the isolation and the sequencing of a nearly full-length NGF cDNA from the Bungarus multicinctus venom gland cDNA library. The structure of the predicted krait precursor resembles that of cobra and of other animals, with a highly conserved mature NGF protein at the carboxy-terminus. Prepro part of the precursors are less conserved. The krait one possesses the presumptive 18 amino residues terminal signal sequence and the two long stretches corresponding to functional domains which are highly conserved alternating with large poorly conserved regions. We discuss particularities in the sequence of the precursor in the krait which may in part explain some earlier results obtained concerning this factor in the krait venom.