title: C-phycocyanin hydration water dynamics in the presence of trehalose: an incoherent elastic neutron scattering study at different energy resolutions.
abstract: We present a study of C-phycocyanin hydration water dynamics in the presence of trehalose by incoherent elastic neutron scattering. By combining data from two backscattering spectrometers with a 10-fold difference in energy resolution we extract a scattering law S(Q,omega) from the Q-dependence of the elastic intensities without sampling the quasielastic range. The hydration water is described by two dynamically different populations--one diffusing inside a sphere and the other diffusing quasifreely--with a population ratio that depends on temperature. The scattering law derived describes the experimental data from both instruments excellently over a large temperature range (235-320 K). The effective diffusion coefficient extracted is reduced by a factor of 10-15 with respect to bulk water at corresponding temperatures. Our approach demonstrates the benefits and the efficiency of using different energy resolutions in incoherent elastic neutron scattering over a large angular range for the study of biological macromolecules and hydration water.
authors.affiliation: Institut de Biologie Structurale Jean-Pierre Ebel, Commissariat à l'Energie Atomique-Centre National de la Recherche Scientifique-Université Joseph Fourier, Grenoble, France. frank.gabel@ibs.fr
authors.forename: Frank
authors.initials: F
authors.lastname: Gabel
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Bellissent-Funel
mesh_terms: D008956:Models, Chemical; D033363:Neutron Diffraction; D010798:Phycocyanin / Q000737:chemistry / Q000378:metabolism*; D014199:Trehalose; D014867:Water / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014867:Water; D010798:Phycocyanin; D014199:Trehalose