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.

From shell to cell: neutron scattering studies of biological water dynamics and coupling to activity

“…By combining EINS data from two spectrometers, Gabel and Bellissent-Funel 8 reported diffusion coefficients of deuterated C-Phycocyanin hydration water, in the presence of trehalose molecules, which are slowed down by a factor of 10-15 with respect to bulk water. As has been pointed out, however, in Gabel et al 9 and by Gabel and Bellissent-Funel 8 , results obtained at different energy resolutions, different wave vector transfers and using different fit models are not directly comparable.…”

Increased molecular mobility in humid silk fibers under tensile stress

“…Thus, we assume a dynamical population c j undergoing unrestricted jump diffusion. The remaining (1 − c j ) of scatterers is composed of a population Φ that undergoes two-site jump diffusion between sites with distance a, and a population (1 − Φ) that diffuses inside a sphere with radius R [16,34,35]:…”

Thermal behaviour of hydrated lysozyme in the presence of sucrose and trehalose by EINS

“…The measured neutron response functions are connected, besides to the structural and dynamical properties of the investigated sample, also with the instrumental features, such as for example the instrumental energy resolution [6][7][8][9], the energy window and the spanned transferred wave vector range [10][11][12][13][14][15][16][17][18]. This implies that the system observables, e.g.…”

“…This implies that the system observables, e.g. distribution functions and mean square displacement (MSD), are influenced by instrumental effects, as, for example, the spatial and dynamical instrumental observation windows [6][7][8][9]. It is well known, in fact, that the instrumental energy resolution, together with the energy window, and the spanned transferred wave vector values determine the time and space ranges of the observable motions.…”