A MODEL FOR THE STRUCTURE OF A HOMODIMERIC PROHORMONE - THE PRECURSORTO THE LOCUST NEUROPEPTIDE AKH-I

We have determined the structure in solution of a homodimeric protein that is a precursor to the locust neuropeptide adipokinetic hormone I using nuclear magnetic resonance spectroscopy. This precursor, called P1, is comprised of two 41 residue strands joined by a single inter-ch ain disulphide at Cys39. We have also determined the structure of an e nd product of P1 processing, called APRP1; this is a homodimer compris ed of residues 14-41 of P1. Nuclear Overhauser Effect (nOe) data indic ate that in both P1 and APRP1, residues 22-37 (numbered with respect t o P1) form pairs of alpha-helices, with no evidence for any other seco ndary structure. (C) 1994 Wiley-Liss, Inc.