Recent Neutron Investigations on Biomolecular Dynamics: From Model Systems towards Complex Macromolecular Machines

Neutron high resolution spectroscopic studies of biomolecular dynamics have been pursued actively in the last decade. They probe macromolecular thermal dynamics in a space-time window of about 1-10A ° and 10-1000 ps, which is involved in biological activity, because this window corresponds to the motions of H-atoms bound to larger groups such as the amino acid side chains. As a result of advances in instrumentation and data analysis methods, it is nowadays possible to obtain quantitative information on the complex low frequency motions exhibited by biologically active systems. In the near future, the advent of new sources and the availability of dedicated instruments will make it possible to extend these studies from "pure" systems, like single proteins, towards more complex ones as protein-lipid and protein-DNA complexes, glyco-lipid systems, ribosomes and even whole cells. Some selected examples highlighting possible future research areas will be illustrated.