Fig. 6.

The potential of mean force in the Φ–Ψ plane averaged over the central seven residues of A₂₁ in the unfolded state with explicit solvent (A) and GB/SA (B). Both are shown at a temperature ≈1.27 times the T_m (456 K and 513 K). Contours are in units of RT at each temperature. Notice that explicit solvent produces a much more diverse distribution of conformations including β, PPII, and left-handed α-helix, but the GB/SA simulation is largely restricted to the α-helical region. This restriction produces a large persistence length and a large mean end-to-end distance with GB/SA compared with explicit solvent. (C) The distribution of end-to-end distances for explicit solvent (red) and GB/SA (black).