Actin dynamics observed by neutron inelastic scattering

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

Actin is one of the most abundant proteins in eukaryotic cells, and expresses a variety of functions related to cell motility. Actin monomers (G-actin) polymerize into the helical F-actin. It has been shown that the multiple functions of F-actin arise from flexibility of F-actin. For understanding flexibility of F-actin and thereby its multiple functions, it is important to understand dynamic properties of F-actin. We employed elastic incoherent and quasielastic neutron scattering, to characterize dynamic properties of F-actin and G-actin. We showed that the dynamics properties of F-actin and G-actin are different. Furthermore, neutron spin-echo experiments of F-actin and G-actin showed that the motions of F-actin and G-actin on nano-scales, described by single relaxation processes, are different. Diffusion constants obtained suggested the effects of internal motions of the actin-protomers.