Fig. 1

The definition of the six side-chain environment categories. This figure shows the classification method of side-chain environment. RSA represents the relative accessible surface areas and F represents the fraction of the whole side-chain area covered by polar atoms. If R S A<0.09, the residue will be placed into class B(buried). If 0.09≤R S A<0.36, the residue will be placed into class P(partial buried). If $\mathit{\text{RSA}}\ge 0.36$, the residue will be placed into class E(exposed). Within class B, if F<0.45, the residue will be placed into B ₁, if 0.45≤F<0.58, the residue will be placed into B ₂, and if $F\ge 0.58$, the residue will be divided into class B ₃. In class P, if F<0.67, the reside will be divided into class P ₁, and if $F\ge 0.67$, the reside will placed into class P ₂