Li, K-M, Wilkinson, C orcid.org/0000-0002-7469-7440, Kellosalo, J et al. (5 more authors) (2016) Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism. Nature Communications, 7. 13596. ISSN 2041-1723
Abstract
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-PPases 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.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2016. 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/ |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) |
Funding Information: | Funder Grant number Royal Society WM120073 Wellcome Trust 091322/Z/10/Z BBSRC BB/M021610/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 08 Nov 2016 09:36 |
Last Modified: | 20 Feb 2019 15:10 |
Published Version: | https://doi.org/10.1038/ncomms13596 |
Status: | Published |
Publisher: | Nature Publishing Group |
Identification Number: | 10.1038/ncomms13596 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106958 |