Quantitative Correlation of Solvent Polarity with the α‐/3₁₀‐Helix Equilibrium: A Heptapeptide Behaves as a Solvent‐Driven Molecular Spring

Abstract

The long and the short of it: Just by changing the polarity of the solvent the highly folded heptapeptide Ac-[Aib-L-(αMe)Val-Aib]2-L-His-NH2 converts from an α into a 310 helix (see picture). The equilibrium constant between the two conformations correlates with the empirical solvent polarity parameter E. Molecular dynamics calculations show that the peptide elongates (310 helix) or shortens (α helix) on switching from one conformation to the other. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2003/z51015_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.