5AW6

Kinetics by X-ray crystallography: Rb+-substitution of bound K+ in the E2.MgF42-.2K+ crystal after 5.5 min

Summary for 5AW6

• Entry DOI: 10.2210/pdb5aw6/pdb
• Related: 5AVQ 5AVR 5AVS 5AVT 5AVU 5AVV 5AVW 5AVX 5AVY 5AVZ 5AW0 5AW1 5AW2 5AW3 5AW4 5AW5 5AW7 5AW8 5AW9
• Descriptor: Na, K-ATPase alpha subunit, 2-acetamido-2-deoxy-beta-D-glucopyranose, Na+,K+-ATPase beta subunit, ... (11 entities in total)
• Functional Keywords: membrane protein, ion pump, atpase, k+ binding, haloacid dehydrogenease superfamily, phosphate analogue, atp-binding, hydrolase, ion transport, nucleotide-binding, phosphoprotein, hydrolase-transport protein complex, kinetics, hydrolase/transport protein
• Biological source: Squalus acanthias (Spiny dogfish); More
• Total number of polymer chains: 3
• Total formula weight: 158242.03

Authors

Ogawa, H.,Cornelius, F.,Hirata, A.,Toyoshima, C. (deposition date: 2015-07-01, release date: 2015-09-02, Last modification date: 2024-10-23)

Primary citation

Ogawa, H.,Cornelius, F.,Hirata, A.,Toyoshima, C.
Sequential substitution of K(+) bound to Na(+),K(+)-ATPase visualized by X-ray crystallography.
Nat Commun, 6:8004-8004, 2015

PubMed Abstract: 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(+).

PubMed: 26258479
DOI: 10.1038/ncomms9004

Experimental method

X-RAY DIFFRACTION (2.8 Å)