Study of the yeast Saccharomyces cerevisiae F 1 F O ‐ATPase ε‐subunit

The yeast Saccharomyces cerevisiae F 1 F O ‐ATPase ε‐subunit (61 residues) was synthesized by the solid‐phase peptide approach under both acidic and basic strategies. Only the latter strategy allowed us to obtain a pure ε‐subunit. The strong propensity of the protein to produce few soluble dimeric species depending on pH has been proved by size‐exclusion chromatography, electrophoresis and mass spectrometry. A circular dichroism study showed that an aqueous solution containing 30% trifluoroethanol or 200 m M sodium dodecyl sulphate is required for helical folding. In both solvents at acidic pH, the ε‐subunit is soluble and monomeric. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.