Single Amino Acid Substitutions in Lattice Proteins Using Statistical Mechanical Model for Protein Folding

Abstract

The folding of lattice proteins with single amino acid substitutions was studied using a statistical mechanical model for protein folding. All possible single amino acid substitutions were analyzed for two different native conformations, and two amino acid sequences foldable to the given native conformation were considered for each native conformation. First, the transition temperature change Δ T m (ξ i ) with the conformational energy change Δ E (ξ i ) caused by the substitution of the amino acid residue type ξ i at the i -th residue was examined. Although both Δ E (ξ i ) and Δ T m (ξ i ) strongly depend on the amino acid sequence (as a result, these two changes for the two proteins with different amino acid sequences foldable to the same native conformation differ considerably from each other), it is indicated that the correlations between Δ E (ξ i ) and Δ T m (ξ i ) for the given residue i of the two proteins are mainly determined by their native conformations and are less dependent on their amino acid...