The dynamics of water in small volumes probed by incoherent quasi-elastic neutron scattering

Abstract

ricevuto il 28 Ottobre 1994)Summary. --The dynamics of water molecules occupying very small volumes can be probed by incoherent quasi-elastic neutron scattering. We summarise some results obtained with wet samples of porous silica and hydrated proteins. The movements of the molecules in the vicinity of the substrate are extremely reduced as compared to those of bulk water at the same temperature. Almost only rotational movements subsist and the local diffusion is of the order of that observed in deeply supercooled water.

Small-angle scattering: a view on the properties, structures and structural changes of biological macromolecules in solution

“…The solution-scattering experiments confirm the higher density in the hydration shell predicted from molecular dynamic simulations (Levitt & Sharon, 1988) and more recently from explicit allatom computations of scattering patterns from proteins accounting for the solvent dynamics (Merzel & Smith, 2002a, b), and reported in several crystallographic studies (Badger, 1993 ;Burling et al 1996). Such a denser water layer, where the movements of water molecules are reduced compared to bulk water (Teixeira, 1994), has also been observed in the vicinity of membranes. Proton migration along such a surface is much faster than exchange with bulk water (see e.g.…”