Abstract
A Monte Carlo simulation of water in a channel with charges suggests the existence of water in immobile, high density, essentially glasslike form near the charges. The channel model has a conical section with an opening through which water molecules can pass, at the narrow end of the cone, and a cylindrical section at the other end. When the charges are placed near the narrow section of the model, the "glass" effectively blocks the channel; with the charges removed, the channel opens. The effect can be determined from the rate of passage of the water molecules through the pore, from the average orientation of the water molecule, and from distortion of the distribution of molecules. In the simulations carried out to date, no external ions have been considered. In addition to the energy, the Helmholtz free energy has been calculated.
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Selected References
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- Ben-Naim A., Ting K. L., Jernigan R. L. Solvation thermodynamics of biopolymers. I. Separation of the volume and surface interactions with estimates for proteins. Biopolymers. 1989 Jul;28(7):1309–1325. doi: 10.1002/bip.360280711. [DOI] [PubMed] [Google Scholar]
- Beveridge D. L., DiCapua F. M. Free energy via molecular simulation: applications to chemical and biomolecular systems. Annu Rev Biophys Biophys Chem. 1989;18:431–492. doi: 10.1146/annurev.bb.18.060189.002243. [DOI] [PubMed] [Google Scholar]
- Bezanilla F., Armstrong C. M. Negative conductance caused by entry of sodium and cesium ions into the potassium channels of squid axons. J Gen Physiol. 1972 Nov;60(5):588–608. doi: 10.1085/jgp.60.5.588. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dani J. A. Ion-channel entrances influence permeation. Net charge, size, shape, and binding considerations. Biophys J. 1986 Mar;49(3):607–618. doi: 10.1016/S0006-3495(86)83688-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Edmonds D. T. A physical model of sodium channel gating. Eur Biophys J. 1987;14(4):195–201. doi: 10.1007/BF00256352. [DOI] [PubMed] [Google Scholar]
- Eisenman G., Dani J. A. An introduction to molecular architecture and permeability of ion channels. Annu Rev Biophys Biophys Chem. 1987;16:205–226. doi: 10.1146/annurev.bb.16.060187.001225. [DOI] [PubMed] [Google Scholar]
- Green M. E. Electrorheological effects and gating of membrane channels. J Theor Biol. 1989 Jun 22;138(4):413–428. doi: 10.1016/s0022-5193(89)80042-6. [DOI] [PubMed] [Google Scholar]
- Keynes R. D., Rojas E. Kinetics and steady-state properties of the charged system controlling sodium conductance in the squid giant axon. J Physiol. 1974 Jun;239(2):393–434. doi: 10.1113/jphysiol.1974.sp010575. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Keynes R. D., Rojas E. The temporal and steady-state relationships between activation of the sodium conductance and movement of the gating particles in the squid giant axon. J Physiol. 1976 Feb;255(1):157–189. doi: 10.1113/jphysiol.1976.sp011274. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leuchtag H. R. Indications of the existence of ferroelectric units in excitable-membrane channels. J Theor Biol. 1987 Aug 7;127(3):321–340. doi: 10.1016/s0022-5193(87)80110-8. [DOI] [PubMed] [Google Scholar]
- Stühmer W., Conti F., Suzuki H., Wang X. D., Noda M., Yahagi N., Kubo H., Numa S. Structural parts involved in activation and inactivation of the sodium channel. Nature. 1989 Jun 22;339(6226):597–603. doi: 10.1038/339597a0. [DOI] [PubMed] [Google Scholar]
- Zimmerberg J., Bezanilla F., Parsegian V. A. Solute inaccessible aqueous volume changes during opening of the potassium channel of the squid giant axon. Biophys J. 1990 May;57(5):1049–1064. doi: 10.1016/S0006-3495(90)82623-0. [DOI] [PMC free article] [PubMed] [Google Scholar]