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Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism

Membrane-bound pyrophosphatases (M-PPases), which couple proton/sodium ion transport to pyrophosphate synthesis/hydrolysis, are important in abiotic stress resistance and in the infectivity of protozoan parasites. Here, three M-PPase structures in different catalytic states show that closure of the...

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Autores principales: Li, Kun-Mou, Wilkinson, Craig, Kellosalo, Juho, Tsai, Jia-Yin, Kajander, Tommi, Jeuken, Lars J. C., Sun, Yuh-Ju, Goldman, Adrian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5150537/
https://www.ncbi.nlm.nih.gov/pubmed/27922000
http://dx.doi.org/10.1038/ncomms13596
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author Li, Kun-Mou
Wilkinson, Craig
Kellosalo, Juho
Tsai, Jia-Yin
Kajander, Tommi
Jeuken, Lars J. C.
Sun, Yuh-Ju
Goldman, Adrian
author_facet Li, Kun-Mou
Wilkinson, Craig
Kellosalo, Juho
Tsai, Jia-Yin
Kajander, Tommi
Jeuken, Lars J. C.
Sun, Yuh-Ju
Goldman, Adrian
author_sort Li, Kun-Mou
collection PubMed
description Membrane-bound pyrophosphatases (M-PPases), which couple proton/sodium ion transport to pyrophosphate synthesis/hydrolysis, are important in abiotic stress resistance and in the infectivity of protozoan parasites. Here, three M-PPase structures in different catalytic states show that closure of the substrate-binding pocket by helices 5–6 affects helix 13 in the dimer interface and causes helix 12 to move down. This springs a ‘molecular mousetrap', repositioning a conserved aspartate and activating the nucleophilic water. Corkscrew motion at helices 6 and 16 rearranges the key ionic gate residues and leads to ion pumping. The pumped ion is above the ion gate in one of the ion-bound structures, but below it in the other. Electrometric measurements show a single-turnover event with a non-hydrolysable inhibitor, supporting our model that ion pumping precedes hydrolysis. We propose a complete catalytic cycle for both proton and sodium-pumping M-PPases, and one that also explains the basis for ion specificity.
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spelling pubmed-51505372016-12-21 Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism Li, Kun-Mou Wilkinson, Craig Kellosalo, Juho Tsai, Jia-Yin Kajander, Tommi Jeuken, Lars J. C. Sun, Yuh-Ju Goldman, Adrian Nat Commun Article Membrane-bound pyrophosphatases (M-PPases), which couple proton/sodium ion transport to pyrophosphate synthesis/hydrolysis, are important in abiotic stress resistance and in the infectivity of protozoan parasites. Here, three M-PPase structures in different catalytic states show that closure of the substrate-binding pocket by helices 5–6 affects helix 13 in the dimer interface and causes helix 12 to move down. This springs a ‘molecular mousetrap', repositioning a conserved aspartate and activating the nucleophilic water. Corkscrew motion at helices 6 and 16 rearranges the key ionic gate residues and leads to ion pumping. The pumped ion is above the ion gate in one of the ion-bound structures, but below it in the other. Electrometric measurements show a single-turnover event with a non-hydrolysable inhibitor, supporting our model that ion pumping precedes hydrolysis. We propose a complete catalytic cycle for both proton and sodium-pumping M-PPases, and one that also explains the basis for ion specificity. Nature Publishing Group 2016-12-06 /pmc/articles/PMC5150537/ /pubmed/27922000 http://dx.doi.org/10.1038/ncomms13596 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Li, Kun-Mou
Wilkinson, Craig
Kellosalo, Juho
Tsai, Jia-Yin
Kajander, Tommi
Jeuken, Lars J. C.
Sun, Yuh-Ju
Goldman, Adrian
Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
title Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
title_full Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
title_fullStr Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
title_full_unstemmed Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
title_short Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism
title_sort membrane pyrophosphatases from thermotoga maritima and vigna radiata suggest a conserved coupling mechanism
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5150537/
https://www.ncbi.nlm.nih.gov/pubmed/27922000
http://dx.doi.org/10.1038/ncomms13596
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