The Structure and Energetics of Helix Formation by Short Templated Peptides in Aqueous Solution. 2. Characterization of the Helical Structure of Ac-Hel1-Ala6-OH

Analysis of NOE cross-peaks in 1 H NMR ROESY spectra of Ac-Hel 1 -Ala 6 -OH in water and in water−trifluoroethanol mixtures demonstrates that the template Ac-Hel 1 initiates an α-helix in a linked hexa-Ala peptide. Other NMR parameters and circular dichroism spectra are consistent with the presence of an α-helix, frayed at the C-terminus. Effects of NaCl, urea, temperature, and trifluoroethanol on the stability of a short alanine helix are reported.