Internal dynamics of actin detected by neutron scattering

Fujiwara, Satoru; Plazanet, M.*; Matsumoto, Fumiko; Oda, Toshiro*

F-actin expresses a variety of functions related to cell motility. To understand how such multiple functions are possible, it is important to understand dynamical properties of F-actin at various levels from internal dynamics of the monomers through relative motions between the monomers to large-scale motions of F-actin. As a first step towards this ultimate purpose, we carried out elastic incoherent neutron scattering (EINS) experiments and quasi-elastic neutron scattering (QENS) experiments of F-actin and G-actin. It was shown from the EINS experiments that there are differences in the internal dynamics of F-actin and G-actin. Analysis of the QENS spectra on F-actin and G-actin showed that both in F-actin and G-actin, there are at least two populations of motions with distinct amplitudes and rates, that higher hydration ratios make these motions "faster", and that G-actin tends to have the motions with larger amplitudes and higher rates than those in F-actin.