Protein and solvent dynamics of the water-soluble chlorophyll-binding protein (WSCP)

This study presents quasielastic neutron scattering data of the water-soluble chlorophyll-binding protein (WSCP) and the corresponding buffer solution at room temperature. The contributions of protein and buffer solution to the overall scattering are carefully separated. Otherwise, the fast water dynamics dominating the buffer contribution is likely to mask the slow protein dynamics. In the case of WSCP, the protein scattering can be described by two contributions: i) internal protein dynamics represented by a diffusion in a sphere with an average radius of 2.7 angstrom and ii) global (Brownian) diffusion of theWSCP macromolecule with an upper limit for the translational diffusion coefficient of 9.4.10(-7) cm(2)/s.