Geobacter bacteria usually prevail among other microorganisms in soils and sediments where Fe(III) reduction has a central role. This reduction is achieved by extracellular electron transfer (EET), where the electrons are exported from the interior of the cell to the surrounding environment. Periplasmic cytochromes play an important role in establishing an interface between inner and outer membrane electron transfer components. In addition, periplasmic cytochromes, in particular nanowire cytochromes that contain at least 12 haem groups, have been proposed to play a role in electron storage in conditions of an environmental lack of electron acceptors. Up to date, no redox partners have been identified in Geobacter sulfurreducens, and concomitantly, the EET and electron storage mechanisms remain unclear. In this work, NMR chemical shift perturbation measurements were used to probe for an interaction between the most abundant periplasmic cytochrome PpcA and the dodecahaem cytochrome GSU1996, one of the proposed nanowire cytochromes in G. sulfurreducens. The perturbations on the haem methyl signals of GSU1996 and PpcA showed that the proteins form a transient redox complex in an interface that involves haem groups from two different domains located at the C-terminal of GSU1996. Overall, the present study provides for the first time a clear evidence for an interaction between periplasmic cytochromes that might be relevant for the EET and electron storage pathways in G. sulfurreducens.
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March 2017
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This confocal microscopic image of an intestinal epithelium exposed to osmotic stress shows localization of nuclei and distribution of tight junction proteins, occludin (green) and ZO-1 (red). Discontinuous junctional distribution of these proteins is an indicator of disrupted tight junctions. For more information please see study by Gangwar et al. in this issue, pages 731–749. Image provided by R.K. Rao
Research Article|
February 20 2017
Interaction studies between periplasmic cytochromes provide insights into extracellular electron transfer pathways of Geobacter sulfurreducens
Ana P. Fernandes;
Ana P. Fernandes
1UCIBIO-Requimte, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
2Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Oeiras, Portugal
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Tiago C. Nunes;
Tiago C. Nunes
1UCIBIO-Requimte, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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Catarina M. Paquete;
2Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Oeiras, Portugal
Correspondence: Catarina M. Paquete ([email protected]) or Carlos A. Salgueiro ([email protected])
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Carlos A. Salgueiro
1UCIBIO-Requimte, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
Correspondence: Catarina M. Paquete ([email protected]) or Carlos A. Salgueiro ([email protected])
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Publisher: Portland Press Ltd
Received:
November 23 2016
Revision Received:
January 13 2017
Accepted:
January 16 2017
Accepted Manuscript online:
January 16 2017
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society
2017
Biochem J (2017) 474 (5): 797–808.
Article history
Received:
November 23 2016
Revision Received:
January 13 2017
Accepted:
January 16 2017
Accepted Manuscript online:
January 16 2017
Citation
Ana P. Fernandes, Tiago C. Nunes, Catarina M. Paquete, Carlos A. Salgueiro; Interaction studies between periplasmic cytochromes provide insights into extracellular electron transfer pathways of Geobacter sulfurreducens. Biochem J 1 March 2017; 474 (5): 797–808. doi: https://doi.org/10.1042/BCJ20161022
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