Visualization of the Interfacial Electrostatic Complementarity: A Method for Analysis of Protein–Protein Interaction Based on Ab Initio Quantum Chemical Calculations

In this study, we report a method for analyzing the protein–protein interaction based on ab initio quantum chemical calculations, which we refer to as “Visualization of the interfacial electrostatic complementarity (VIINEC).” This method visually provides the electrostatic complementarity at the protein–protein interface; in addition, the ratio of the attractive interaction is calculated. Illustrative calculations revealed that VIINEC could successfully quantify the electronic induced fit owing complex formation, which was responsible for 5%–10% of the total electrostatic complementarity. Furthermore, the contribution of each amino acid to the electrostatic complementarity was evaluated, providing useful information for various applications, including rational antibody designs. Interestingly, a part of the mechanism causing the specificity of the protein–protein bindings was also demonstrated using VIINEC. This is an important achievement of this study because the specificity of the biomolecular interactions is essential for biological functions.