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Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient
Biological membranes are barriers to polar molecules, so membrane embedded proteins control the transfers between cellular compartments. Protein controlled transport moves substrates and activates cellular signaling cascades. In addition, the electrochemical gradient across mitochondrial, bacterial...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8239185/ https://www.ncbi.nlm.nih.gov/pubmed/34211960 http://dx.doi.org/10.3389/fchem.2021.660954 |
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author | Kaur, Divya Khaniya, Umesh Zhang, Yingying Gunner, M. R. |
author_facet | Kaur, Divya Khaniya, Umesh Zhang, Yingying Gunner, M. R. |
author_sort | Kaur, Divya |
collection | PubMed |
description | Biological membranes are barriers to polar molecules, so membrane embedded proteins control the transfers between cellular compartments. Protein controlled transport moves substrates and activates cellular signaling cascades. In addition, the electrochemical gradient across mitochondrial, bacterial and chloroplast membranes, is a key source of stored cellular energy. This is generated by electron, proton and ion transfers through proteins. The gradient is used to fuel ATP synthesis and to drive active transport. Here the mechanisms by which protons move into the buried active sites of Photosystem II (PSII), bacterial RCs (bRCs) and through the proton pumps, Bacteriorhodopsin (bR), Complex I and Cytochrome c oxidase (CcO), are reviewed. These proteins all use water filled proton transfer paths. The proton pumps, that move protons uphill from low to high concentration compartments, also utilize Proton Loading Sites (PLS), that transiently load and unload protons and gates, which block backflow of protons. PLS and gates should be synchronized so PLS proton affinity is high when the gate opens to the side with few protons and low when the path is open to the high concentration side. Proton transfer paths in the proteins we describe have different design features. Linear paths are seen with a unique entry and exit and a relatively straight path between them. Alternatively, paths can be complex with a tangle of possible routes. Likewise, PLS can be a single residue that changes protonation state or a cluster of residues with multiple charge and tautomer states. |
format | Online Article Text |
id | pubmed-8239185 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-82391852021-06-30 Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient Kaur, Divya Khaniya, Umesh Zhang, Yingying Gunner, M. R. Front Chem Chemistry Biological membranes are barriers to polar molecules, so membrane embedded proteins control the transfers between cellular compartments. Protein controlled transport moves substrates and activates cellular signaling cascades. In addition, the electrochemical gradient across mitochondrial, bacterial and chloroplast membranes, is a key source of stored cellular energy. This is generated by electron, proton and ion transfers through proteins. The gradient is used to fuel ATP synthesis and to drive active transport. Here the mechanisms by which protons move into the buried active sites of Photosystem II (PSII), bacterial RCs (bRCs) and through the proton pumps, Bacteriorhodopsin (bR), Complex I and Cytochrome c oxidase (CcO), are reviewed. These proteins all use water filled proton transfer paths. The proton pumps, that move protons uphill from low to high concentration compartments, also utilize Proton Loading Sites (PLS), that transiently load and unload protons and gates, which block backflow of protons. PLS and gates should be synchronized so PLS proton affinity is high when the gate opens to the side with few protons and low when the path is open to the high concentration side. Proton transfer paths in the proteins we describe have different design features. Linear paths are seen with a unique entry and exit and a relatively straight path between them. Alternatively, paths can be complex with a tangle of possible routes. Likewise, PLS can be a single residue that changes protonation state or a cluster of residues with multiple charge and tautomer states. Frontiers Media S.A. 2021-06-15 /pmc/articles/PMC8239185/ /pubmed/34211960 http://dx.doi.org/10.3389/fchem.2021.660954 Text en Copyright © 2021 Kaur, Khaniya, Zhang and Gunner. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Chemistry Kaur, Divya Khaniya, Umesh Zhang, Yingying Gunner, M. R. Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient |
title | Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient |
title_full | Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient |
title_fullStr | Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient |
title_full_unstemmed | Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient |
title_short | Protein Motifs for Proton Transfers That Build the Transmembrane Proton Gradient |
title_sort | protein motifs for proton transfers that build the transmembrane proton gradient |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8239185/ https://www.ncbi.nlm.nih.gov/pubmed/34211960 http://dx.doi.org/10.3389/fchem.2021.660954 |
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