Dynamics of biomolecules by neutron inelastic scattering

Nakagawa, Hiroshi   

Protein is a functional element in all living organisms. Almost all vital phenomena are mediated by specific proteins. Proteins work in an aqueous environment at ambient temperature, indicating that proteins cannot escape from thermal fluctuations. The magnitude of physiologically relevant input is as the same level as thermal fluctuations. It is widely accepted that the proteins are flexible and mobile. The flexibility and mobility, that is, protein dynamics are essential for protein functions. Understanding of protein dynamics is also important to clarify how the proteins can discriminate physiologically relevant motions from random fluctuations. Neutron incoherent scattering is one of the most powerful techniques to observe protein dynamics quantitatively, for example, vibration and diffusion dynamics. The next-generation neutron source, J-PARC, in Ibaraki was constructed and a several neutron instruments are already working. We expect that the neutron source will open new era for biophysics. Here I will talk about dynamics of protein and its hydration water, and discuss the prospect of the dynamics study of biomolecules at the J-PARC.