[Application of Brownian dynamics to the description of transmembrane ion flow as exemplified by the chloride channel of glycine receptor].
Using the Brownian dynamics of the movement of hydrated ion in a viscous water solution, a mathematical model has been built, which describes the transport of charged particles through a single protein pore in a lipid membrane. The dependences of transmembrane ion currents on ion concentrations in solution have been obtained. It was shown that, if the geometry of a membrane pore is identical to that of the inner part of the glycine receptor channel and there is no ion selectivity, then the values of both chloride and sodium currents are not greater than 0.5 pA at the physiological concentrations of these ions. If local charge heterogeneity caused by charged amino acid residues of transmembrane protein segments is included into the model calculations, the chloride current increases to about 3.7 pA, which exceeds more than seven times the value for sodium ions under the conditions of the complex channel geometry in the range of physiological concentrations of ions in the solution. The model takes changes in the density of charge distribution both inside the channel and near the protein surface into account. The alteration of pore geometry can be also considered as a parameter at the researcher's option. Thus, the model appears as an effective tool for the description of transmembrane currents for other types of membrane channels.
Boronovskiĭ
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SE
Nartsissov
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IaR
D000465:Algorithms; D000595:Amino Acid Sequence; D055592:Biophysical Phenomena; D002462:Cell Membrane / Q000737:chemistry; D018118:Chloride Channels / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D008954:Models, Biological; D008956:Models, Chemical; D008969:Molecular Sequence Data; D018009:Receptors, Glycine / Q000737:chemistry*
D018118:Chloride Channels; D007477:Ions; D018009:Receptors, Glycine