Rotational Mobility of Water around Muscle Proteins by High-Resolution Microwave Dielectric Spectroscopy and a Clue to Molecular Mechanism of Muscle Contraction

Abstract

A precision microwave dielectric spectroscopic technique has been developed. This technique enables us to analyze hydration properties of ions, proteins, and other biomolecules. φ-scan method gives an image of the information of spatial distribution of dielectric property of water surrounding protein molecules. Fixed φ analysis gives a direct comparison of hydration properties of different proteins. With this technique we analyzed the state change of F-actin hydration upon binding with myosin, and found that hyper-mobile water (HMW) is induced around F-actin and increased upon binding with myosin S1. Thus, we may obtain further information of collective properties of water surrounding proteins and biomolecules.