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

Kavita Garg, Mihir Ghosh, Tamar Eliash, Jessica H. Van Wonderen, Julea N. Butt, Liang Shi, Xiuyun Jiang, Futera Zdenek, Jochen Blumberger, Israel Pecht, Mordechai Sheves, David Cahen

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Multi-heme cytochrome c (Cytc) proteins are key for transferring electrons out of cells, to enable intracellular oxidation to proceed 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 proteins: MtrF (deca-heme Cytc) and STC (tetra-heme Cytc). Transport is measured across monolayers of these proteins in a solid state configuration between Au electrodes. Both proteins showed 1000× higher conductance than single heme, or heme-free proteins, but similar conductance to monolayers of conjugated organics. Conductance is found to be temperature-independent (320-80 K), suggesting tunneling as the transport mechanism. This mechanism is consistent with I-V curves modelling, results of which could be interpreted by having protein-electrode coupling as rate limiting, rather than transport within the proteins.

Original languageEnglish
Pages (from-to)7304-7310
Number of pages7
JournalChemical Science
Issue number37
StatePublished - 2018
Externally publishedYes

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© The Royal Society of Chemistry 2018.


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