Ion Channels, Nanotubes in Living Cells
Living cells are surrounded by a lipid bilayer that separates the internal from the external media. As the very hydrophobic nature of the core of the lipid bilayer prevents the exchange of charged species between the interior and exterior of the cell, there are specialized structures inserted in the lipid bilayer that carry out the exchange of ions. These structures are integral membrane proteins that may be classified as transporters, ion pumps and ion channels. Of special interest here are the ion channels which are proteins specialized to conduct ions across the membrane with the distinguishing characteristic that the ionic flow is driven exclusively by the electrochemical gradient of the conducted ionic species. These channels are found in the cell surface membrane and also in membranes of internal cell compartments.
KeywordsSelectivity Filter Electrochemical Gradient Proton Channel Conducting Pore KcsA Channel
Many thanks to Dr. R. Latorre for reading the manuscript. Supported by NIH grant GM030376.
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