Protein Conformational Changes and Low-Frequency Vibrational Modes: A Similarity Analysis

The study of protein vibration and dynamics is receiving increasing attention among researchers, both from a numerical and experimental perspective. By using terahertz spectroscopy techniques, it has been shown that conformational changes, crucial for protein biological function, are strictly related to low-frequency vibrational modes. These motions generally occur in the terahertz range (~0.1–2 THz) involving large portions of the protein. The present contribution aims at investigating the role of terahertz (expansion-contraction) vibrational modes to protein conformational change from a numerical viewpoint. Modal analysis is performed by using Cα-only coarse-grained mechanical models: the obtained mode shapes are compared, by means of three similarity indexes, to the displacement field of protein conformational change. In particular, lysine-arginine-ornithine (LAO) binding protein is selected as a case study.