Sandbox Reserved 969: Difference between revisions
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Ion channels are '''transmembrane proteins''' which allow ions to pass through biological membranes. | Ion channels are '''transmembrane proteins''' which allow ions to pass through biological membranes. | ||
Some of these channels are very selective, others have a low level of selectivity. The NaK channel is a | Some of these channels are very selective, others have a low level of selectivity. The NaK channel is a | ||
'''non-selective''' one : It conduits cations more than anions but it let pass several cations : Na+, K+, Rb+, and Ca2+ <ref> | '''non-selective''' one : It conduits cations more than anions but it let pass several cations : Na+, K+, Rb+, and Ca2+ <ref> PMC3183810 </ref> | ||
Understanding how these channels work is important because in the organism a lot of '''messages''' are transmitted through electric currents (which are '''ionic currents''' across the membrane) : nerves impulse, photoreceptors, etc. Thus, these not very selective NaK channels are very interesting for the inhibition of intercellular messages for instance. | Understanding how these channels work is important because in the organism a lot of '''messages''' are transmitted through electric currents (which are '''ionic currents''' across the membrane) : nerves impulse, photoreceptors, etc. Thus, these not very selective NaK channels are very interesting for the inhibition of intercellular messages for instance. | ||
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The NaK channel is like an '''intracellular gate'''. | The NaK channel is like an '''intracellular gate'''. | ||
The NaK channel have the same general architecture as the K+ channels. In fact, the NaK channel has '''4 subunits''' which are '''symmetric''' with respect to the central axis of the pore. Each subunit is composed of '''3 alpha-helices'''. One of them is a short pore helix which is oblique to the channel axis. The others are the outer and the inner helices and they extend across the lipid membrane. <ref> | The NaK channel have the same general architecture as the K+ channels. In fact, the NaK channel has '''4 subunits''' which are '''symmetric''' with respect to the central axis of the pore. Each subunit is composed of '''3 alpha-helices'''. One of them is a short pore helix which is oblique to the channel axis. The others are the outer and the inner helices and they extend across the lipid membrane. <ref> PMC3183810 </ref> | ||
===Structure of the open or closed complex=== | ===Structure of the open or closed complex=== | ||
