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Photoreduction of Shewanella oneidensis Extracellular Cytochromes by Organic Chromophores and Dye-Sensitized TiO2.

Published version
Peer-reviewed

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Authors

Ainsworth, Emma V 
Lockwood, Colin WJ 
White, Gaye F 
Hwang, Ee Taek 
Sakai, Tsubasa 

Abstract

The transfer of photoenergized electrons from extracellular photosensitizers across a bacterial cell envelope to drive intracellular chemical transformations represents an attractive way to harness nature's catalytic machinery for solar-assisted chemical synthesis. In Shewanella oneidensis MR-1 (MR-1), trans-outer-membrane electron transfer is performed by the extracellular cytochromes MtrC and OmcA acting together with the outer-membrane-spanning porin⋅cytochrome complex (MtrAB). Here we demonstrate photoreduction of solutions of MtrC, OmcA, and the MtrCAB complex by soluble photosensitizers: namely, eosin Y, fluorescein, proflavine, flavin, and adenine dinucleotide, as well as by riboflavin and flavin mononucleotide, two compounds secreted by MR-1. We show photoreduction of MtrC and OmcA adsorbed on RuII -dye-sensitized TiO2 nanoparticles and that these protein-coated particles perform photocatalytic reduction of solutions of MtrC, OmcA, and MtrCAB. These findings provide a framework for informed development of strategies for using the outer-membrane-associated cytochromes of MR-1 for solar-driven microbial synthesis in natural and engineered bacteria.

Description

Keywords

cytochromes, electron transfer, heme proteins, photocatalysis, photoreduction, Bacterial Outer Membrane Proteins, Catalysis, Coloring Agents, Cytochrome c Group, Electron Transport, Eosine Yellowish-(YS), Ferric Compounds, Flavin Mononucleotide, Light, Metal Nanoparticles, Oxidation-Reduction, Photosensitizing Agents, Shewanella, Titanium

Journal Title

Chembiochem

Conference Name

Journal ISSN

1439-4227
1439-7633

Volume Title

17

Publisher

Wiley
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/K010220/1)
This work was supported by the UK Biotechnology and Biological Sciences Research Council (grants BB/K009753/1, BB/K010220/1, BB/K009885/1, and BB/K00929X/1), the Engineering and Physical Sciences Research Council (EP/M001989/1, PhD studentship 1307196 to E.V.A.), a Royal Society Leverhulme Trust Senior Research Fellowship to J.N.B., the Christian Doppler Research Association, and OMV group.