THE STRUCTURE OF THE RODENT AND PORCINE NEUROPEPTIDE GALANIN AND ANTAGONISTS AS DETERMINED BY FTIR AND CD SPECTROSCOPY

FT-IR spectroscopy was used to study the conformation of the porcine neuropeptide galanin, fragments 1-16 of the porcine and human peptides and the antagonists M15 and M35. All peptides were shown to be structureless in aqueous solution. Upon addition to SDS micelles, only porcine galanin and the fragment consisting of amino acids 1-16 showed any evidence of interaction, adopting a helical structure. No interaction could be demonstrated with zwitterionic lipids for any peptide except M15 which formed a thermally unstable helical conformation which unfolded promoting aggregation at around 45 degrees C. Additional studies on rat galanin in various solvent systems were made by using circular dichroism spectroscopy. The results obtained support the observations made by FT-IR spectroscopy.