7y46
From Proteopedia
Cryo-EM structure of the Na+,K+-ATPase in the E2.2K+ state after addition of ATP
Structural highlights
FunctionC4IX13_SQUAC This is the non-catalytic component of the active enzyme, which catalyzes the hydrolysis of ATP coupled with the exchange of Na(+) and K(+) ions across the plasma membrane.[RuleBase:RU004369] Publication Abstract from PubMedNa(+) ,K(+) -ATPase (NKA) is one of the most important members of the P-type ion-translocating ATPases and plays a pivotal role in establishing electrochemical gradients for Na(+) and K(+) across the cell membrane. Presented here is a 3.3 A resolution structure of NKA in the E2.2K(+) state solved by cryo-electron microscopy. It is a stable state with two occluded K(+) after transferring three Na(+) into the extracellular medium and releasing inorganic phosphate bound to the cytoplasmic P domain. We describe how the extracellular ion pathway wide open in the E2P state becomes closed and locked in E2.2K(+) , linked to events at the phosphorylation site more than 50 A away. We also show, although at low resolution, how ATP binding to NKA in E2.2K(+) relaxes the gating machinery and thereby accelerates the transition into the next step, that is, the release of K(+) into the cytoplasm, more than 100 times. Cryo-electron microscopy of Na(+) ,K(+) -ATPase reveals how the extracellular gate locks in the E2.2K(+) state.,Kanai R, Cornelius F, Vilsen B, Toyoshima C FEBS Lett. 2022 Oct;596(19):2513-2524. doi: 10.1002/1873-3468.14437. Epub 2022 , Jul 6. PMID:35747985[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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