6JXI

Rb+-bound E2-MgF state of the gastric proton pump (Tyr799Trp)

Summary for 6JXI

• Entry DOI: 10.2210/pdb6jxi/pdb
• Descriptor: Potassium-transporting ATPase alpha chain 1, Potassium-transporting ATPase subunit beta, TETRAFLUOROMAGNESATE(2-), ... (10 entities in total)
• Functional Keywords: p-type atpase, proton pump, gastric, ion pump, membrane protein
• Biological source: Sus scrofa (Pig); More
• Total number of polymer chains: 2
• Total formula weight: 148020.71

Authors

Abe, K.,Irie, K. (deposition date: 2019-04-23, release date: 2019-08-14, Last modification date: 2023-11-22)

Primary citation

Yamamoto, K.,Dubey, V.,Irie, K.,Nakanishi, H.,Khandelia, H.,Fujiyoshi, Y.,Abe, K.
A single K + -binding site in the crystal structure of the gastric proton pump.
Elife, 8:-, 2019

PubMed Abstract: The gastric proton pump (H,K-ATPase), a P-type ATPase responsible for gastric acidification, mediates electro-neutral exchange of H and K coupled with ATP hydrolysis, but with an as yet undetermined transport stoichiometry. Here we show crystal structures at a resolution of 2.5 Å of the pump in the E2-P transition state, in which the counter-transporting cation is occluded. We found a single K bound to the cation-binding site of the H,K-ATPase, indicating an exchange of 1H/1K per hydrolysis of one ATP molecule. This fulfills the energy requirement for the generation of a six pH unit gradient across the membrane. The structural basis of K recognition is resolved and supported by molecular dynamics simulations, establishing how the H,K-ATPase overcomes the energetic challenge to generate an H gradient of more than a million-fold-one of the highest cation gradients known in mammalian tissue-across the membrane.

PubMed: 31436534
DOI: 10.7554/eLife.47701

Experimental method

X-RAY DIFFRACTION (2.6 Å)