Cation-limited kinetic model for microbial extracellular electron transport via an outer membrane cytochrome C complex

• Okamoto Akihiro

  Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science (NIMS) Department of Applied Chemistry, School of Engineering, The University of Tokyo

• Tokunou Yoshihide

  Department of Applied Chemistry, School of Engineering, The University of Tokyo

• Saito Junki

  Department of Applied Chemistry, School of Engineering, The University of Tokyo

書誌事項

タイトル別名

• Cation-limited kinetic model for microbial extracellular electron transport via an outer membrane cytochrome <i>C</i> complex

抄録

Outer-membrane c-type cytochrome (OM c-Cyt) complexes in several genera of iron-reducing bacteria, such as Shewanella and Geobacter, are capable of transporting electrons from the cell interior to extracellular solids as a terminal step of anaerobic respiration. The kinetics of this electron transport has implications for controlling the rate of microbial electron transport during bioenergy or biochemical production, iron corrosion, and natural mineral cycling. Herein, we review the findings from in-vivo and in-vitro studies examining electron transport kinetics through single OM c-Cyt complexes in Shewanella oneidensis MR-1. In-vitro electron flux via a purified OM c-Cyt complex, comprised of MtrA, B, and C proteins from S. oneidensis MR-1, embedded in a proteoliposome system is reported to be 10- to 100-fold faster compared with in-vivo estimates based on measurements of electron flux per cell and OM c-Cyts density. As the proteoliposome system is estimated to have 10-fold higher cation flux via potassium channels than electrons, we speculate that the slower rate of electron-coupled cation transport across the OM is responsible for the significantly lower electron transport rate that is observed in-vivo. As most studies to date have primarily focused on the energetics or kinetics of interheme electron hopping in OM c-Cyts in this microbial electron transport mechanism, the proposed model involving cation transport provides new insight into the rate detemining step of EET, as well as the role of self-secreted flavin molecules bound to OM c-Cyt and proton management for energy conservation and production in S. oneidensis MR-1.

収録刊行物

• Biophysics and Physicobiology

  Biophysics and Physicobiology 13 (0), 71-76, 2016

  一般社団法人 日本生物物理学会

キーワード

• <i>Shewanella oneidensis</i> MR-1
• electrochemistry
• proton motive force
• iron-reducing bacteira
• flavin

詳細情報

• CRID: 1390001205763456512
• NII論文ID: 130005154008
• DOI: 10.2142/biophysico.13.0_71
• ISSN: 21894779
• Web Site: https://www.jstage.jst.go.jp/article/biophysico/13/0/13_71/_pdf
• 本文言語コード: en
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