ACTIVE CONFORMATION OF THE PYROKININ PBAN NEUROPEPTIDE FAMILY FOR PHEROMONE BIOSYNTHESIS IN THE SILKWORM

Members of the pyrokinin/pheromone biosynthesis activating neuropeptide family elicit pheromonotropic activity in at least two species of moths. We report that in the silkworm(Bombyx mori) the conformationally constrained octapeptide analog cyclo[Asn-Thr-Ser-Phe-Thr-Pro-Arg-Leu] retains 10% of the pheromonotropic activity of naturally occurring Bom-PBAN-I, a 33 amino acid peptide. Previous data from CD, NMR, and molecular dynamics analyses indicate a type I β-turn conformation for active core residues Thr-Pro-Arg-Leu in the cyclic analog. The rigidity of the well-defined backbone structure of this cyclic pyrokinin/PBAN analog suggests that it represents the conformation necessary to interact with the pheromonotropic receptor site in the silkworm. © 1993 Academic Press, Inc.