Sandbox Reserved 811: Difference between revisions
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Sodium potassium pump is sensitive to the membrane potential, the binding and dissociation of one of the three Na+ ions is voltage-dependent. | Sodium potassium pump is sensitive to the membrane potential, the binding and dissociation of one of the three Na+ ions is voltage-dependent. | ||
3Na+ are bound to the pump in the E1 conformation, ATP is already bound to the α-subunit. It is open to the intracellular milieu of the cell, once 3 Na+ bound it becomes transiently inaccessible to both sides of the plasma membrane. The binding of the sodium ions induces the movement of the A domain: there is occlusion of 2Na+ and hydrolysis of ATP at the P domain. ADP and Na+ bound at the C-terminal domain are released to the extracellular milieu. The pump adopts the E2 conformation and opens to the exterior of the cell. | 3Na+ are bound to the pump in the E1 conformation, ATP is already bound to the α-subunit. It is open to the intracellular milieu of the cell, once 3 Na+ bound it becomes transiently inaccessible to both sides of the plasma membrane. The binding of the sodium ions induces the movement of the A domain: there is occlusion of 2Na+ and hydrolysis of ATP at the P domain. ADP and Na+ bound at the C-terminal domain are released to the extracellular milieu. The pump adopts the E2 conformation and opens to the exterior of the cell. | ||
There is an exchange between 2Na+ and 2K+. The α-subunit occludes the potassium ions, inorganic phosphate still bound. Pi is coordinated by the loop of Thr 212, Gly 213, Glu 214 and Ser 215. | There is an exchange between 2Na+ and 2K+. The α-subunit occludes the potassium ions, inorganic phosphate still bound. Pi is coordinated by the loop of <scene name='56/568009/Interaction_with_pi/1'>Thr 212, Gly 213, Glu 214 and Ser 215</scene>. | ||
The enzyme converts to the E1 conformation that induces the replacement of Pi by H2O and the release of K+. | The enzyme converts to the E1 conformation that induces the replacement of Pi by H2O and the release of K+. | ||