Conformations of the dermenkephalin backbone in DMSO solution by a new approach to the solution conformations of flexible peptides

Dermenkephalin (DRE, H-Tyr-D-Met-Phe-His-Leu-Met-Asp-NH 2 ), a natural peptide found in frog skin, has high potency and receptor selectivity for δ opioid receptors and has potent in vivo analgesic activity. Structurally the compound is related to both the μ opioid receptor selective dermorphin and the δ opioid receptor selective deltorphins. Interestingly, the N-terminal tetrapeptide of DRE is potent and selective for the μ opioid receptor. Efforts to understand the conformational properties of DRE and their relationships to biological activity are of great importance. We report here a novel approach to analyze conformations of short linear peptides in solution to determine the possible solution conformations of DRE