PMID- 23576738
OWN - NLM
STAT- MEDLINE
DCOM- 20130719
LR  - 20211021
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 110
IP  - 19
DP  - 2013 May 7
TI  - Rate enhancement of bacterial extracellular electron transport involves bound 
      flavin semiquinones.
PG  - 7856-61
LID - 10.1073/pnas.1220823110 [doi]
AB  - Extracellular redox-active compounds, flavins and other quinones, have been 
      hypothesized to play a major role in the delivery of electrons from cellular 
      metabolic systems to extracellular insoluble substrates by a diffusion-based 
      shuttling two-electron-transfer mechanism. Here we show that flavin molecules 
      secreted by Shewanella oneidensis MR-1 enhance the ability of its outer-membrane 
      c-type cytochromes (OM c-Cyts) to transport electrons as redox cofactors, but not 
      free-form flavins. Whole-cell differential pulse voltammetry revealed that the 
      redox potential of flavin was reversibly shifted more than 100 mV in a positive 
      direction, in good agreement with increasing microbial current generation. 
      Importantly, this flavin/OM c-Cyts interaction was found to facilitate a 
      one-electron redox reaction via a semiquinone, resulting in a 10(3)- to 
      10(5)-fold faster reaction rate than that of free flavin. These results are not 
      consistent with previously proposed redox-shuttling mechanisms but suggest that 
      the flavin/OM c-Cyts interaction regulates the extent of extracellular electron 
      transport coupled with intracellular metabolic activity.
FAU - Okamoto, Akihiro
AU  - Okamoto A
AD  - Department of Applied Chemistry, School of Engineering, The University of Tokyo, 
      Tokyo 113-8656, Japan.
FAU - Hashimoto, Kazuhito
AU  - Hashimoto K
FAU - Nealson, Kenneth H
AU  - Nealson KH
FAU - Nakamura, Ryuhei
AU  - Nakamura R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20130401
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Cytochrome c Group)
RN  - 0 (Nucleotides)
RN  - 146-14-5 (Flavin-Adenine Dinucleotide)
RN  - 35919-91-6 (flavin semiquinone)
RN  - 42VZT0U6YR (Heme)
RN  - 7N464URE7E (Flavin Mononucleotide)
RN  - 9007-43-6 (Cytochromes c)
RN  - EC 1.- (MtrC protein, Shewanella)
SB  - IM
CIN - Proc Natl Acad Sci U S A. 2013 May 7;110(19):7537-8. PMID: 23630260
MH  - Biofilms
MH  - Cytochrome c Group/*metabolism
MH  - Cytochromes c/metabolism
MH  - Electrochemistry
MH  - Electrodes
MH  - Electron Spin Resonance Spectroscopy
MH  - *Electron Transport
MH  - Flavin Mononucleotide/metabolism
MH  - Flavin-Adenine Dinucleotide/*analogs & derivatives/metabolism
MH  - Heme/metabolism
MH  - Microscopy, Confocal
MH  - Nucleotides/genetics
MH  - Oxidation-Reduction
MH  - Shewanella/metabolism/*physiology
PMC - PMC3651484
OTO - NOTNLM
OT  - electromicrobiology
OT  - flavin mononucleotide
OT  - iron-reducing bacteria
OT  - microbial fuel cell
OT  - whole-cell voltammetry
COIS- The authors declare no conflict of interest.
EDAT- 2013/04/12 06:00
MHDA- 2013/07/20 06:00
PMCR- 2013/04/01
CRDT- 2013/04/12 06:00
PHST- 2013/04/12 06:00 [entrez]
PHST- 2013/04/12 06:00 [pubmed]
PHST- 2013/07/20 06:00 [medline]
PHST- 2013/04/01 00:00 [pmc-release]
AID - 1220823110 [pii]
AID - 201220823 [pii]
AID - 10.1073/pnas.1220823110 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 2013 May 7;110(19):7856-61. doi: 
      10.1073/pnas.1220823110. Epub 2013 Apr 1.