Solution structure and dynamics of the outer membrane cytochrome OmcF from Geobacter sulfurreducens

Gene knock-out studies on Geobacter sulfurreducens cells showed that the outer membrane-associated monoheme cytochrome OmcF is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI). In addition, microarray analysis of an OmcF-deficient mutant revealed that many...

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Bibliographic Details
Published in:Biochimica et biophysica acta. Bioenergetics 2017-09, Vol.1858 (9), p.733-741
Main Authors: Dantas, Joana M., Silva, Marta A., Pantoja-Uceda, David, Turner, David L., Bruix, Marta, Salgueiro, Carlos A.
Format: Article
Language:English
Subjects:
Bacterial Proteins - chemistry
Geobacter - chemistry
Geobacter sulfurreducens
Heme - chemistry
Models, Molecular
Motion
NMR
Nuclear Magnetic Resonance, Biomolecular
Outer membrane cytochrome
Oxidation-Reduction
Peptide Fragments - chemistry
Protein Conformation
Recombinant Proteins - chemistry
Redox protein
Solution structure
Solutions
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Summary:Gene knock-out studies on Geobacter sulfurreducens cells showed that the outer membrane-associated monoheme cytochrome OmcF is involved in respiratory pathways leading to the extracellular reduction of Fe(III) and U(VI). In addition, microarray analysis of an OmcF-deficient mutant revealed that many of the genes with decreased transcript level were those whose expression is up-regulated in cells grown with a graphite electrode as electron acceptor, suggesting that OmcF also regulates the electron transfer to electrode surfaces and the concomitant electricity production by G. sulfurreducens in microbial fuel cells. 15N,13C–labeled OmcF was produced and NMR spectroscopy was used to determine the solution structure of the protein in the fully reduced state and the pH-dependent conformational changes. In addition, 15N relaxation NMR experiments were used to characterize the overall and internal backbone dynamics of OmcF. The structure obtained is well-defined, with an average pairwise root mean square deviation of 0.37Å for the backbone atoms and 0.98Å for all heavy atoms. For the first time a solution structure and the protein motions were determined for an outer membrane cytochrome from G. sulfurreducens, which constitutes an important step to understand the extracellular electron transfer mechanism in Geobacter cells. •The solution structure of OmcF from G. sulfurreducens was determined.•The internal dynamics of OmcF was probed by 15N relaxation NMR.•A polypeptide region was proposed to interact with OmcF partners.•The OmcF redox-Bohr center was identified.
ISSN:0005-2728
1879-2650
DOI:10.1016/j.bbabio.2017.03.007