Conformation of physalaemin

Abstract

The conformational and spatial configuration of the biologically active undecapeptide physalaemin was studied using 350-MHz 1H NMR. The NMR analyses suggested the existence of a strong hydrogen bond between the amide proton of the Phe7 and a carbonyl group in the N-terminal moiety most likely the Pro4 one. Other bondings were postulated, involving the side-chain amine of Lys6 and the side-chain amide of Asn5 and respectively the side-chain carboxyl of Asp3 and the terminal amide carbonyl of Met-NH2. Thus unlike its shorter peptide fragments, physalaemin exhibited a stable molecular structure in solution, giving some insight into the conformation required for interaction at the biological receptor of tachykinins.