Fig. 1.

Computed total helix content (Left) and mean residue ellipticity at 222 nm (Right) for the C peptide as a function of simulation pH. The solid lines with open symbols represent the simulation data obtained at 0.1 M ionic strength, whereas the dashed lines represent the data obtained in pure water. The black lines with filled symbols represent the experimental [θ]₂₂₂ values estimated from the work of Bierzynski et al. (5). The computed helix content is based on the ratio between the number of helical residues and total number of residues. The uncertainty in helix content is estimated to be 2% (see Methods). The computed mean residue ellipticity for all pH values is shifted down by 2,000 deg·cm²·dmol⁻¹ to facilitate the comparison of the pH-induced changes in mean residue ellipticity with experiment.