Did you try and read the abstract? The meaning of dynamics is quite readily apparent. I've bolded phrases from the abstract that might be helpful.
"The biological activity of protein molecules depends on their structural fluctuations. Recent theoretical studies have helped to clarify the nature and function of these fluctuations. Because proteins are large densely-packed structures their atomic motions can be compared to those that occur in other dense materials. Small motions at short times are similar to what is observed in liquids. Larger motions in proteins are opposed by the forces that stabilise their native structures, resulting in solid-like features. Of special importance is the strong coupling observed between local and collective displacements; this coupling governs the character of many ligand-binding processes and structural transformations that are essential to biological function."