5aw0

Kinetics by X-ray crystallography: Tl+-substitution of bound K+ in the E2.MgF42-.2K+ crystal after 55 min

spinqualitylabelsall models 5aw0, resolution 3.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5aw0 is a 3 chain structure with sequence from Squalus acanthias. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.3Å Ligands: CLR, K, MF4, MG, NAG, TL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function C4IX13_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 PubMed Na(+),K(+)-ATPase transfers three Na(+) from the cytoplasm into the extracellular medium and two K(+) in the opposite direction per ATP hydrolysed. The binding and release of Na(+) and K(+) are all thought to occur sequentially. Here we demonstrate by X-ray crystallography of the ATPase in E2.MgF4(2-).2K(+), a state analogous to E2.Pi.2K(+), combined with isotopic measurements, that the substitution of the two K(+) with congeners in the extracellular medium indeed occurs at different rates, substantially faster at site II. An analysis of thermal movements of protein atoms in the crystal shows that the M3-M4E helix pair opens and closes the ion pathway leading to the extracellular medium, allowing K(+) at site II to be substituted first. Taken together, these results indicate that site I K(+) is the first cation to bind to the empty cation-binding sites after releasing three Na(+). Sequential substitution of K(+) bound to Na(+),K(+)-ATPase visualized by X-ray crystallography.,Ogawa H, Cornelius F, Hirata A, Toyoshima C Nat Commun. 2015 Aug 10;6:8004. doi: 10.1038/ncomms9004. PMID:26258479 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also ATPase 3D structures

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