Conformation of physalaemin

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 peptidic fragments, physalaemin exhibited a stable molecular structure in solution, giving some insight into the conformation required for interaction at the biological receptor of tachykinins.