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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...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2016
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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. |
format | Online Article Text |
id | pubmed-5150537 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
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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