Fig. 2.

Equilibrium thermal denaturation of A₂₁ and F_s peptides in GB/SA by using the parm94 and parm-mod force fields. (Upper) The mean number of hydrogen bonds. (Lower) The average number of helices. The curves and error bars are computed as in Fig. 1. Unlike in explicit solvent (Fig. 1), at high temperatures the F_s peptide has the same helical content as A₂₁, and at lower temperatures with the parm94 force field it is less helical. The low-temperature behavior is caused by the experimentally incorrect formation of structures with multiple helices.