Dynamics of F-actin, myosin subfragment-1 (S1), and their hydration water studied by quasielastic neutron scattering

Matsuo, Tatsuhito; Arata, Toshiaki*; Oda, Toshiro*; Fujiwara, Satoru

The picosecond dynamics of F-actin, myosin S1, and their hydration water were studied by quasielastic neutron scattering (QENS) at J-PARC. Analysis of the QENS spectra showed that a larger fraction of the atoms of F-actin undergoes the motions with the smaller residence time than S1. It was also found that the mobility of the hydration water of S1, which was evaluated from the translational diffusion coefficient, the residence time, and the rotational correlation time, is lower than that of bulk water, while that of the hydration water of F-actin is close to that of bulk water. These results suggest that the concerted action of rapidly fluctuating F-actin and its hydration water allows F-actin to explore a wide range of the conformational space, which would facilitate the binding of myosin to F-actin.