Li , K-M , Wilkinson , C , Kellosalo , J , Tsai , J-Y , Kajander , T , Jeuken , L J C , Sun , Y-J & Goldman , A 2016 , ' Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism ' , Nature Communications , vol. 7 , 13596 . https://doi.org/10.1038/ncomms13596
Title: | Membrane pyrophosphatases from Thermotoga maritima and Vigna radiata suggest a conserved coupling mechanism |
Author: | Li, Kun-Mou; Wilkinson, Craig; Kellosalo, Juho; Tsai, Jia-Yin; Kajander, Tommi; Jeuken, Lars J. C.; Sun, Yuh-Ju; Goldman, Adrian |
Contributor organization: | Institute of Biotechnology Biosciences Biochemistry and Biotechnology |
Date: | 2016-12-06 |
Language: | eng |
Number of pages: | 11 |
Belongs to series: | Nature Communications |
ISSN: | 2041-1723 |
DOI: | https://doi.org/10.1038/ncomms13596 |
URI: | http://hdl.handle.net/10138/172747 |
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-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. |
Subject: |
VACUOLAR H+-PYROPHOSPHATASE
PUMPING PYROPHOSPHATASE CRYSTAL-STRUCTURE ROTARY MECHANISM NA+ SODIUM PROTEINS TRANSLOCATION PURIFICATION TRANSPORT 1182 Biochemistry, cell and molecular biology |
Peer reviewed: | Yes |
Rights: | cc_by |
Usage restriction: | openAccess |
Self-archived version: | publishedVersion |
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