Structure—Function Relationship of PBAN/MRCH

Abstract

Pheromone biosynthesis activating neuropeptides (PBANs) (Raina and Klun 1984) are C-terminally amidated neuropeptides that regulate sex pheromone biosynthesis in moths. To date, four different PBAN molecules were isolated and their primary structures have been determined. The first PBAN molecule (33 amino acids) was isolated from Helicoverpa zea (Hez-PBAN; Raina et al. 1989a). Two other molecules were isolated from Bombyx mori, Bom-PBAN-I (33 amino acids), and Bom-PBAN-II (34 amino acids) (Kitamura et al. 1989, 1990). A fourth molecule (33 amino acids) was recently isolated from Lymantria dispar (LydPBAN, Masler et al. 1994). Hez-PBAN shares about 80% homology with BomPBAN and Lyd-PBAN. The C-terminal pentapeptide (Phe-Xxx-Pro-Arg-LeuNH2, Xxx = Ser) of all four PBAN molecules is identical and shares homology with the C-terminal pentapeptide of the pyrokinins, a family of myotropic peptides isolated from Leucophea maderae and Locusta migratoria (Xxx = Ser, Gly, Thr, Val; Schoofs et al. 1993). This C-terminal part is also homologous to the C-terminal region of two other neuropeptides: Pseudaletia separata pheromonotropin (Pss-PT, 18 amino acids) (Matsumoto et al. 1992a) and B. mori diapause hormone (Bom-DH) (Imai et al. 1991). The PBAN gene of H. zea (Davis et al. 1992b; Ma et al. 1994) and the c-DNA of B. mori PBAN (Kawano et al. 1992; Sato et al. 1993) have recently been cloned. In both moths the gene sequences contain, in addition to the PBAN sequence, peptides having the common C-terminal pentapeptide (Phe-Xxx-Pro-Arg-Leu-NH2) (Sato et al. 1993; Ma et al. 1994).