Direct evidence for heme-assisted solid-state electronic conduction in multi-heme c-type cytochromes

Garg, Kavita, Ghosh, Mihir, Eliash, Tamar, van Wonderen, Jessica H., Butt, Julea N., Shi, Liang, Jiang, Xiuyun, Zdeněk, Futera, Blumberger, Jochen, Pecht, Israel, Sheves, Mordechai and Cahen, David (2018) Direct evidence for heme-assisted solid-state electronic conduction in multi-heme c-type cytochromes. Chemical Science, 9 (37). pp. 7304-7310. ISSN 2041-6520

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Multi-heme cytochrome c (CytC) proteins are key for transferring electrons out of cells, to enable intracellular oxidation to proceed, also in the absence of O2. In these proteins most of the hemes are arranged in a linear array suggesting a facile path for electronic conduction. To test this, we studied solvent free electron transport across two multi-heme CytC-type: MtrF (deca-heme CytC) and STC (tetra-heme CytC). Transport is measured across monolayers of these proteins in solid state configuration between Au electrodes. Both proteins showed 1,000x higher conductance than single heme, or heme-free proteins, but similar to monolayers of conjugated organics. Conductances are found to be temperature-independent (320-80K), suggesting tunneling as the transport mechanism based on present experimental data. This mechanism is consistent with modelling the I-V curves, results of which could be interpreted by having protein-electrode coupling as rate limiting, rather than transport within the proteins.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
Depositing User: LivePure Connector
Date Deposited: 30 Jul 2018 09:30
Last Modified: 13 Oct 2021 01:41
DOI: 10.1039/C8SC01716F

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