A single K+-binding site in the crystal structure of the gastric proton pump

Kenta Yamamoto, Vikas Dubey, Katsumasa Irie, Hanayo Nakanishi, Himanshu Khandelia, Yoshinori Fujiyoshi, Kazuhiro Abe

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Resumé

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 A° 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.

OriginalsprogEngelsk
Artikelnummere47701
TidsskrifteLife
Vol/bind8
Antal sider22
ISSN2050-084X
DOI
StatusUdgivet - 22. aug. 2019

Fingeraftryk

Proton Pumps
Adenosine Triphosphatases
Cations
Crystal structure
Binding Sites
Hydrolysis
Membranes
Adenosine Triphosphate
Molecular Dynamics Simulation
Acidification
Stoichiometry
Molecular dynamics
Pumps
Molecules
Computer simulation

Citer dette

Yamamoto, Kenta ; Dubey, Vikas ; Irie, Katsumasa ; Nakanishi, Hanayo ; Khandelia, Himanshu ; Fujiyoshi, Yoshinori ; Abe, Kazuhiro. / A single K+-binding site in the crystal structure of the gastric proton pump. I: eLife. 2019 ; Bind 8.
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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 A° 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.",
keywords = "biochemistry, chemical biology, E. coli, gastric, human, membrane transport, molecular biophysics, P-type ATPase, proton pump, structural biology",
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A single K+-binding site in the crystal structure of the gastric proton pump. / Yamamoto, Kenta; Dubey, Vikas; Irie, Katsumasa; Nakanishi, Hanayo; Khandelia, Himanshu; Fujiyoshi, Yoshinori; Abe, Kazuhiro.

I: eLife, Bind 8, e47701, 22.08.2019.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - A single K+-binding site in the crystal structure of the gastric proton pump

AU - Yamamoto, Kenta

AU - Dubey, Vikas

AU - Irie, Katsumasa

AU - Nakanishi, Hanayo

AU - Khandelia, Himanshu

AU - Fujiyoshi, Yoshinori

AU - Abe, Kazuhiro

PY - 2019/8/22

Y1 - 2019/8/22

N2 - 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 A° 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.

AB - 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 A° 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.

KW - biochemistry

KW - chemical biology

KW - E. coli

KW - gastric

KW - human

KW - membrane transport

KW - molecular biophysics

KW - P-type ATPase

KW - proton pump

KW - structural biology

U2 - 10.7554/eLife.47701

DO - 10.7554/eLife.47701

M3 - Journal article

VL - 8

JO - eLife

JF - eLife

SN - 2050-084X

M1 - e47701

ER -