Dynamics of hydration water around F-actin detected by neutron scattering

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

The dynamics of the hydration water around F-actin and S1 (which are proteins interacting with each other to produce force in muscle contraction) were investigated by quasielastic neutron scattering (QENS). The QENS measurements were carried out on the solution samples of F-actin and S1 in HO and DO using AMATERAS in MLF/J-PARC, Japan. It was found that the D values (the translational diffusion coefficient) of the hydration water around S1 are smaller than those of bulk water while the values (the residence time) were larger than those of bulk water, suggesting that S1 has typical hydration water, the mobility of which is less than that of bulk water. On the other hand, the D values of the hydration water around F-actin are much closer to those of bulk water although the values were similar to those of S1, suggesting that the hydration water around F-actin has higher mobility than that around other proteins including S1.