Conformation of a biologically active C-terminal hexapeptide analog of the pheromone biosynthesis activating neuropeptide by NMR spectroscopy

The solution conformation of a biologically active C-terminal hexapeptide analog of the pheromone biosynthesis activating neuropeptide Tyr-d -Phe-Ser-Pro-Arg-Leu-NH₂ has been studied by NMR spectroscopy. A β-turn conformation was identified from the NOE connectivities observed for the peptide in a mixed solvent of water and DMSO, indicating that this is the biologically active conformation of the peptide. This study also suggests that the use of such an aqueous-like solvent mixture allows the observation of a preferred conformation for small linear peptides in the presence of conformational averaging.