Direct evidence for heme-assisted solid-state electronic conduction in multi-heme c-type cytochromes. Issue 37 (13th August 2018)

• Record Type: Journal Article
• Authors: Garg, Kavita; Ghosh, Mihir; Eliash, Tamar; van Wonderen, Jessica H.; Butt, Julea N.; Shi, Liang; Jiang, Xiuyun; Zdenek, Futera; Blumberger, Jochen; Pecht, Israel; Sheves, Mordechai; Cahen, David
• Is Part Of: Chemical science. Volume 9:Issue 37(2018)
• Page Start: 7304
• Page End: 7310
• Publication Date: 2018-08-13
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc01716f
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : We study solvent-free electron transport across two multi-heme cytochrome c-type proteins, MtrF and STC, and find that they are better at conducting than non- or mono heme proteins. Abstract : Multi-heme cytochrome c (Cyt c ) 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 Cyt c -type proteins: MtrF (deca-heme Cyt c ) and STC (tetra-heme Cyt c ). 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.