COMP 215 |
| We have used computer simulations to study the unusual dynamics, structure, and thermodynamics of water in weakly polar pores and cavities formed by carbon nanotubes, fullerenes, and proteins. In the absence of strong interactions with the pore walls, water molecules tend to form wires or clusters held together by tight and long-lived hydrogen bonds. The structures of water clusters confined into roughly spherical cavities resemble those seen experimentally in gas phase. The thermodynamics of water filling the pores and cavities from an equilibrium solvent is determined by a subtle balance between the substantial loss in hydrogen bond interactions upon removal of water from the bulk phase, compensated by strong hydrogen-bond interactions between confined water molecules, weakly attractive interactions between water and the pore, an entropic gain from filling a void space, and significant rotational freedom of confined water clusters. The simulation results are compared directly to recent high pressure crystallography data for T4 lysozyme that provided a first direct experimental demonstration of a “drying” transition in a protein (Collins et al., Proc. Natl. Acad. Sci. USA 102, 16668, 2005). Implications on a possible role of such interfacial and confined water in protein function will be discussed. |
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Recent Advances in Studies of Molecular Processes at Interfaces
8:30 AM-12:30 PM, Tuesday, August 21, 2007 BCEC -- 156C, Oral
Division of Computers in Chemistry |