Biologically significant conformation of the Saccharomyces cerevisiae α‐factor

The conformation of the tridecapeptide α‐factor of the yeast Saccharomyces cerevisiae was examined in both solution and in the presence of lipid vesicles. CD, differential scanning calorimetry, and phosphorus nmr all indicate that this mating pheromone interacts with lipid vesicles. In both aqueous and organic solution of the α‐factor is a flexible molecule that exhibits features of a type II β‐turn spanning the center of the peptide. Two‐dimensional Nuclear Overhauser enhancement spectroscopy gives evidence that the β‐turn is stabilized on interaction of the peptide with lipid vesicles. Our current belief is that the β‐turn may play an important role in the biologically active conformation of the α‐factor.