Reduction of low potential electron acceptors requires the CbcL inner membrane cytochrome of Geobacter sulfurreducens

Zacharoff, Lori; Chan, Chi Ho; Bond, Daniel R.

doi:10.1016/j.bioelechem.2015.08.003

Title: Reduction of low potential electron acceptors requires the CbcL inner membrane cytochrome of Geobacter sulfurreducens

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Abstract

The respiration of metals by the bacterium Geobacter sulfurreducens requires electrons generated by metabolism to pass from the interior of the cell to electron acceptors beyond the cell membranes. The G. sulfurreducens inner membrane multiheme c-type cytochrome ImcH is required for respiration to extracellular electron acceptors with redox potentials greater than - 0.1 V vs. SHE, but ImcH is not essential for electron transfer to lower potential acceptors. In contrast, deletion of cbcL, encoding an inner membrane protein consisting of b-type and multiheme c-type cytochrome domains, severely affected reduction of low potential electron acceptors such as Fe(III)-oxides and electrodes poised at - 0.1 V vs. SHE. Catalytic cyclic voltammetry of a ΔcbcL strain growing on poised electrodes revealed a 50 mV positive shift in driving force required for electron transfer out of the cell. In non-catalytic conditions, low-potential peaks present in wild type biofilms were absent in ΔcbcL mutants. Expression of cbcL in trans increased growth at low redox potential and restored features to cyclic voltammetry. This evidence supports a model where CbcL is a component of a second electron transfer pathway out of the G. sulfurreducens inner membrane that dominates when redox potential is at or below - 0.1more » V vs. SHE.« less

Authors:

Zacharoff, Lori;

; Bond, Daniel R.

Publication Date:: Mon Feb 01 00:00:00 EST 2016

Research Org.:: Univ. of Minnesota, Minneapolis, MN (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Biological and Environmental Research (BER); Office of Naval Research (ONR) (United States)

OSTI Identifier:: 1222041

Alternate Identifier(s):: OSTI ID: 1437113

Grant/Contract Number:: SC0006868; N0001410308

Resource Type:: Published Article

Journal Name:: Bioelectrochemistry

Additional Journal Information:: Journal Name: Bioelectrochemistry Journal Volume: 107 Journal Issue: C; Journal ID: ISSN 1567-5394

Publisher:: Elsevier

Country of Publication:: Netherlands

Language:: English

Subject:: 59 BASIC BIOLOGICAL SCIENCES; extracellular respiration; metal reduction; Geobacter; cytochrome; microbial electrochemical cell

Citation Formats


                    Zacharoff, Lori, Chan, Chi Ho, and Bond, Daniel R. Reduction of low potential electron acceptors requires the CbcL inner membrane cytochrome of Geobacter sulfurreducens.  Netherlands: N. p., 2016. 
Web.  doi:10.1016/j.bioelechem.2015.08.003.

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                    Zacharoff, Lori, Chan, Chi Ho, & Bond, Daniel R. Reduction of low potential electron acceptors requires the CbcL inner membrane cytochrome of Geobacter sulfurreducens.  Netherlands.  https://doi.org/10.1016/j.bioelechem.2015.08.003

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                    Zacharoff, Lori, Chan, Chi Ho, and Bond, Daniel R. Mon .  
"Reduction of low potential electron acceptors requires the CbcL inner membrane cytochrome of Geobacter sulfurreducens".  Netherlands.  https://doi.org/10.1016/j.bioelechem.2015.08.003.

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@article{osti_1222041,

  title        = {Reduction of low potential electron acceptors requires the CbcL inner membrane cytochrome of Geobacter sulfurreducens},

  author       = {Zacharoff, Lori and Chan, Chi Ho and Bond, Daniel R.},

  abstractNote = {The respiration of metals by the bacterium Geobacter sulfurreducens requires electrons generated by metabolism to pass from the interior of the cell to electron acceptors beyond the cell membranes. The G. sulfurreducens inner membrane multiheme c-type cytochrome ImcH is required for respiration to extracellular electron acceptors with redox potentials greater than - 0.1 V vs. SHE, but ImcH is not essential for electron transfer to lower potential acceptors. In contrast, deletion of cbcL, encoding an inner membrane protein consisting of b-type and multiheme c-type cytochrome domains, severely affected reduction of low potential electron acceptors such as Fe(III)-oxides and electrodes poised at - 0.1 V vs. SHE. Catalytic cyclic voltammetry of a ΔcbcL strain growing on poised electrodes revealed a 50 mV positive shift in driving force required for electron transfer out of the cell. In non-catalytic conditions, low-potential peaks present in wild type biofilms were absent in ΔcbcL mutants. Expression of cbcL in trans increased growth at low redox potential and restored features to cyclic voltammetry. This evidence supports a model where CbcL is a component of a second electron transfer pathway out of the G. sulfurreducens inner membrane that dominates when redox potential is at or below - 0.1 V vs. SHE.},

  doi          = {10.1016/j.bioelechem.2015.08.003},

  journal      = {Bioelectrochemistry},

  number       = C,

  volume       = 107,

  place        = {Netherlands},

  year         = {Mon Feb 01 00:00:00 EST 2016},

  month        = {Mon Feb 01 00:00:00 EST 2016}

}

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