Blog
About

  • Record: found
  • Abstract: found
  • Article: found
Is Open Access

Cell-secreted Flavins Bound to Membrane Cytochromes Dictate Electron Transfer Reactions to Surfaces with Diverse Charge and pH

Read this article at

Bookmark
      There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

      Abstract

      The variety of solid surfaces to and from which microbes can deliver electrons by extracellular electron transport (EET) processes via outer-membrane c-type cytochromes (OM c-Cyts) expands the importance of microbial respiration in natural environments and industrial applications. Here, we demonstrate that the bifurcated EET pathway of OM c-Cyts sustains the diversity of the EET surface in Shewanella oneidensis MR-1 via specific binding with cell-secreted flavin mononucleotide (FMN) and riboflavin (RF). Microbial current production and whole-cell differential pulse voltammetry revealed that RF and FMN enhance EET as bound cofactors in a similar manner. Conversely, FMN and RF were clearly differentiated in the EET enhancement by gene-deletion of OM c-Cyts and the dependency of the electrode potential and pH. These results indicate that RF and FMN have specific binding sites in OM c-Cyts and highlight the potential roles of these flavin-cytochrome complexes in controlling the rate of electron transfer to surfaces with diverse potential and pH.

      Related collections

      Most cited references 33

      • Record: found
      • Abstract: found
      • Article: not found

      T-Coffee: A novel method for fast and accurate multiple sequence alignment.

      We describe a new method (T-Coffee) for multiple sequence alignment that provides a dramatic improvement in accuracy with a modest sacrifice in speed as compared to the most commonly used alternatives. The method is broadly based on the popular progressive approach to multiple alignment but avoids the most serious pitfalls caused by the greedy nature of this algorithm. With T-Coffee we pre-process a data set of all pair-wise alignments between the sequences. This provides us with a library of alignment information that can be used to guide the progressive alignment. Intermediate alignments are then based not only on the sequences to be aligned next but also on how all of the sequences align with each other. This alignment information can be derived from heterogeneous sources such as a mixture of alignment programs and/or structure superposition. Here, we illustrate the power of the approach by using a combination of local and global pair-wise alignments to generate the library. The resulting alignments are significantly more reliable, as determined by comparison with a set of 141 test cases, than any of the popular alternatives that we tried. The improvement, especially clear with the more difficult test cases, is always visible, regardless of the phylogenetic spread of the sequences in the tests. Copyright 2000 Academic Press.
        Bookmark
        • Record: found
        • Abstract: found
        • Article: not found

        Bug juice: harvesting electricity with microorganisms.

         Derek Lovley (2006)
        It is well established that some reduced fermentation products or microbially reduced artificial mediators can abiotically react with electrodes to yield a small electrical current. This type of metabolism does not typically result in an efficient conversion of organic compounds to electricity because only some metabolic end products will react with electrodes, and the microorganisms only incompletely oxidize their organic fuels. A new form of microbial respiration has recently been discovered in which microorganisms conserve energy to support growth by oxidizing organic compounds to carbon dioxide with direct quantitative electron transfer to electrodes. These organisms, termed electricigens, offer the possibility of efficiently converting organic compounds into electricity in self-sustaining systems with long-term stability.
          Bookmark
          • Record: found
          • Abstract: found
          • Article: not found

          Iron and manganese in anaerobic respiration: environmental significance, physiology, and regulation.

          Dissimilatory iron and/or manganese reduction is known to occur in several organisms, including anaerobic sulfur-reducing organisms such as Geobacter metallireducens or Desulfuromonas acetoxidans, and facultative aerobes such as Shewanella putrefaciens. These bacteria couple both carbon oxidation and growth to the reduction of these metals, and inhibitor and competition experiments suggest that Mn(IV) and Fe(III) are efficient electron acceptors similar to nitrate in redox abilities and capable of out-competing electron acceptors of lower potential, such as sulfate (sulfate reduction) or CO2 (methanogenesis). Field studies of iron and/or manganese reduction suggest that organisms with such metabolic abilities play important roles in coupling the oxidation of organic carbon to metal reduction under anaerobic conditions. Because both iron and manganese oxides are solids or colloids, they tend to settle downward in aquatic environments, providing a physical mechanism for the movement of oxidizing potential into anoxic zones. The resulting biogeochemical metal cycles have a strong impact on many other elements including carbon, sulfur, phosphorous, and trace metals.
            Bookmark

            Author and article information

            Affiliations
            [1 ]Departments of Earth Sciences and Biological Sciences, University of Southern California , Los Angeles, CA 90089
            [2 ]Department of Applied Chemistry, University of Tokyo , Bunkyo-ku, Tokyo, 113-8654
            [3 ]Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science , Wako, Saitama 351-0198, Japan
            [4 ]J. Craig Venter Institute , San Diego, CA 92121
            Author notes
            Journal
            Sci Rep
            Sci Rep
            Scientific Reports
            Nature Publishing Group
            2045-2322
            11 July 2014
            2014
            : 4
            4092373
            srep05628
            10.1038/srep05628
            Copyright © 2014, Macmillan Publishers Limited. All rights reserved

            This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder in order to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

            Categories
            Article

            Uncategorized

            Comments

            added an editorial note to Shewanella

            To further elucidate the role of flavins in extracellular electron transfer (EET) in Shewanella, Okamoto et al perform an electrochemical investigation and conclude that rather than randomly mediating EET in their soluble forms, different flavins interact specifically with their respective outer membrane cytochromes in a bifurcated EET mechanism.

            2016-03-21 13:40 UTC
            +1

            Comment on this article