Fig. 3.

Hydration properties. (a) Radial distribution, g_CO(r), of the distance, r, between the water oxygen atoms and the peptide surface hydrophobic-residue carbon atoms (circles, H1 hydrophobic analog; solid line, H1 peptide calculated for structures with ρ_w^pho ≤ 16.75 nm⁻²). (b) H1 peptide hydration density around hydrophobic, ρ_w^pho (solid line), and hydrophilic, ρ_w^phi (dotted line), residues as a function of the fraction of the solvent-accessible surface area that is hydrophobic, f_pho. Nearly identical results are found when S_pho is used instead of f_pho. ρ_w^pho (ρ_w^phi) is defined here as the number of water molecules, N_w, within a 0.55-nm (0.45-nm) radius cutoff from every hydrophobic (hydrophilic) atom on the peptide surface per unit of exposed hydrophobic (hydrophilic) surface area (ρ_w^pho = N_w/S_pho; ρ_w^phi = N_w/S_phi). ρ_w^pho was also calculated for the H1 hydrophobic analog, and the average value is shown as a gray line.