Fig. 1.

E_env (16) vs. chain length. E_env quantifies solvation and hydrophobic effects and has been parameterized by using a database of 500 soluble proteins (small circles) (16). For each protein structure, E_env=∑_i ε(a_i, r_a,i, ρ_Cβ) where for the ith residue a_i, r_a,i, and ρ_Cβ are the amino acid, side chain conformation, and local density of β carbons. Also shown is the E_env for WT KcsA (open circle) and the value E_env that was used as a constraint in the sequence calculations (black circle).