Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: Kaur, Divya, Khaniya, Umesh, Zhang, Yingying, Gunner, M. R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
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
_version_ 1783715024831774720
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
work_keys_str_mv AT kaurdivya proteinmotifsforprotontransfersthatbuildthetransmembraneprotongradient
AT khaniyaumesh proteinmotifsforprotontransfersthatbuildthetransmembraneprotongradient
AT zhangyingying proteinmotifsforprotontransfersthatbuildthetransmembraneprotongradient
AT gunnermr proteinmotifsforprotontransfersthatbuildthetransmembraneprotongradient