Cytochrome c Provides an Electron-Funneling Antenna for Efficient Photocurrent Generation in a Reaction Center Biophotocathode

Friebe, Vincent M., Millo, Diego, Swainsbury, David J.K., Jones, Michael R. and Frese, Raoul N. (2017) Cytochrome c Provides an Electron-Funneling Antenna for Efficient Photocurrent Generation in a Reaction Center Biophotocathode. ACS Applied Materials and Interfaces, 9 (28). pp. 23379-23388. ISSN 1944-8244

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The high quantum efficiency of photosynthetic reaction centers (RCs) makes them attractive for bioelectronic and biophotovoltaic applications. However, much of the native RC efficiency is lost in communication between surface-bound RCs and electrode materials. The state-of-the-art biophotoelectrodes utilizing cytochrome c (cyt c) as a biological wiring agent have at best approached 32% retained RC quantum efficiency. However, bottlenecks in cyt c-mediated electron transfer have not yet been fully elucidated. In this work, protein film voltammetry in conjunction with photoelectrochemistry is used to show that cyt c acts as an electron-funneling antennae that shuttle electrons from a functionalized rough silver electrode to surface-immobilized RCs. The arrangement of the two proteins on the electrode surface is characterized, revealing that RCs attached directly to the electrode via hydrophobic interactions and that a film of six cyt c per RC electrostatically bound to the electrode. We show that the additional electrical connectivity within a film of cyt c improves the high turnover demands of surface-bound RCs. This results in larger photocurrent onset potentials, positively shifted half-wave reduction potentials, and higher photocurrent densities reaching 100 μA cm-2. These findings are fundamental for the optimization of bioelectronics that utilize the ubiquitous cyt c redox proteins as biological wires to exploit electrode-bound enzymes.

Item Type: Article
Additional Information: Funding Information: M.R.J. and D.J.K.S. acknowledge support from the Biotechnology and Biological Sciences Research Council of the U.K. (project BB/I022570/1). R.N.F. acknowledges support from the Dutch Science Foundation NWO for a vidi grant, and D.M. for a veni grant (no. 722.011.003). Molecular graphics were performed with the UCSF Chimera package. Chimera is developed by the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco (supported by NIGMS P41-GM103311). Publisher Copyright: © 2017 American Chemical Society.
Uncontrolled Keywords: biophotoelectrochemistry,biophotovoltaics,biosolar cells,cytochrome c,reaction center,materials science(all) ,/dk/atira/pure/subjectarea/asjc/2500
Faculty \ School: Faculty of Science > School of Biological Sciences
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Depositing User: LivePure Connector
Date Deposited: 17 Aug 2022 12:31
Last Modified: 22 Oct 2022 07:55
DOI: 10.1021/acsami.7b03278

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