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Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens

The bacterium Gs (Geobacter sulfurreducens) is capable of oxidizing a large variety of compounds relaying electrons out of the cytoplasm and across the membranes in a process designated as extracellular electron transfer. The trihaem cytochrome PpcA is highly abundant in Gs and is most probably the...

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Autores principales: Morgado, Leonor, Dantas, Joana M., Simões, Telma, Londer, Yuri Y., Pokkuluri, P. Raj, Salgueiro, Carlos A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Portland Press Ltd. 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3522473/
https://www.ncbi.nlm.nih.gov/pubmed/23030844
http://dx.doi.org/10.1042/BSR20120086
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author Morgado, Leonor
Dantas, Joana M.
Simões, Telma
Londer, Yuri Y.
Pokkuluri, P. Raj
Salgueiro, Carlos A.
author_facet Morgado, Leonor
Dantas, Joana M.
Simões, Telma
Londer, Yuri Y.
Pokkuluri, P. Raj
Salgueiro, Carlos A.
author_sort Morgado, Leonor
collection PubMed
description The bacterium Gs (Geobacter sulfurreducens) is capable of oxidizing a large variety of compounds relaying electrons out of the cytoplasm and across the membranes in a process designated as extracellular electron transfer. The trihaem cytochrome PpcA is highly abundant in Gs and is most probably the reservoir of electrons destined for the outer surface. In addition to its role in electron transfer pathways, we have previously shown that this protein could perform e(−)/H(+) energy transduction. This mechanism is achieved by selecting the specific redox states that the protein can access during the redox cycle and might be related to the formation of proton electrochemical potential gradient across the periplasmic membrane. The regulatory role of haem III in the functional mechanism of PpcA was probed by replacing Met(58), a residue that controls the solvent accessibility of haem III, with serine, aspartic acid, asparagine or lysine. The data obtained from the mutants showed that the preferred e(−)/H(+) transfer pathway observed for PpcA is strongly dependent on the reduction potential of haem III. It is striking to note that one residue can fine tune the redox states that can be accessed by the trihaem cytochrome enough to alter the functional pathways.
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spelling pubmed-35224732012-12-28 Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens Morgado, Leonor Dantas, Joana M. Simões, Telma Londer, Yuri Y. Pokkuluri, P. Raj Salgueiro, Carlos A. Biosci Rep Original Paper The bacterium Gs (Geobacter sulfurreducens) is capable of oxidizing a large variety of compounds relaying electrons out of the cytoplasm and across the membranes in a process designated as extracellular electron transfer. The trihaem cytochrome PpcA is highly abundant in Gs and is most probably the reservoir of electrons destined for the outer surface. In addition to its role in electron transfer pathways, we have previously shown that this protein could perform e(−)/H(+) energy transduction. This mechanism is achieved by selecting the specific redox states that the protein can access during the redox cycle and might be related to the formation of proton electrochemical potential gradient across the periplasmic membrane. The regulatory role of haem III in the functional mechanism of PpcA was probed by replacing Met(58), a residue that controls the solvent accessibility of haem III, with serine, aspartic acid, asparagine or lysine. The data obtained from the mutants showed that the preferred e(−)/H(+) transfer pathway observed for PpcA is strongly dependent on the reduction potential of haem III. It is striking to note that one residue can fine tune the redox states that can be accessed by the trihaem cytochrome enough to alter the functional pathways. Portland Press Ltd. 2012-11-30 /pmc/articles/PMC3522473/ /pubmed/23030844 http://dx.doi.org/10.1042/BSR20120086 Text en © 2013 The Author(s). http://creativecommons.org/licenses/by-nc/2.5/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial Licence (http://creativecommons.org/licenses/by-nc/2.5/) which permits unrestricted non-commercial use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Paper
Morgado, Leonor
Dantas, Joana M.
Simões, Telma
Londer, Yuri Y.
Pokkuluri, P. Raj
Salgueiro, Carlos A.
Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens
title Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens
title_full Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens
title_fullStr Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens
title_full_unstemmed Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens
title_short Role of Met(58) in the regulation of electron/proton transfer in trihaem cytochrome PpcA from Geobacter sulfurreducens
title_sort role of met(58) in the regulation of electron/proton transfer in trihaem cytochrome ppca from geobacter sulfurreducens
topic Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3522473/
https://www.ncbi.nlm.nih.gov/pubmed/23030844
http://dx.doi.org/10.1042/BSR20120086
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