Ultrafast light-driven electron transfer in a Ru(II)tris(bipyridine)-labelled multiheme cytochrome

van Wonderen, Jessica H., Hall, Christopher R., Jiang, Xiuyun, Adamczyk, Katrin, Carof, Antoine, Heisler, Ismael, Piper, Samuel E. H., Clarke, Thomas A. ORCID: https://orcid.org/0000-0002-6234-1914, Watmough, Nicholas J., Sazanovich, Igor V., Towrie, Michael, Meech, Stephen R. ORCID: https://orcid.org/0000-0001-5561-2782, Blumberger, Jochen and Butt, Julea N. ORCID: https://orcid.org/0000-0002-9624-5226 (2019) Ultrafast light-driven electron transfer in a Ru(II)tris(bipyridine)-labelled multiheme cytochrome. Journal of the American Chemical Society, 141 (38). pp. 15190-15200. ISSN 0002-7863

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Abstract

Multiheme cytochromes attract much attention for their electron transport properties. These proteins conduct electrons across bacterial cell walls, along extracellular filaments, and when purified can serve as bionanoelectronic junctions. Thus, it is important and necessary to identify and understand the factors governing electron transfer in this family of proteins. To this end we have used ultra-fast transient absorbance spectroscopy, to define heme-heme electron transfer dynamics in the representative multiheme cytochrome STC from Shewanella oneidensis in aqueous solution. STC was photo-sensitized by site-selective labelling with a Ru(II)(bipyridine)3 dye and the dynamics of light-driven electron transfer described by a kinetic model corroborated by molecular dynamics simulation and density functional theory calculations. With the dye attached adjacent to STC Heme IV, a rate constant of 87 x 106 s-1 was resolved for Heme IV → Heme III electron transfer. With the dye attached adjacent to STC Heme I, at the opposite terminus of the tetraheme chain, a rate constant of 125 x 106 s-1 was defined for Heme I → Heme II electron transfer. These rates are an order of magnitude faster than previously computed values for unlabeled STC. The Heme III/IV and I/II pairs exemplify the T-shaped heme packing arrangement, prevalent in multiheme cytochromes, whereby the adjacent porphyrin rings lie at 90o with edge-edge (Fe-Fe) distances of ≈6 (11) Å. The results are significant in demonstrating the opportunities for pump-probe spectroscopies to resolve inter-heme electron transfer in Ru-labeled multiheme cytochromes.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Chemistry Faculty of Science > School of Biological Sciences Faculty of Science > School of Natural Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Molecular Microbiology Faculty of Science > Research Groups > Chemistry of Light and Energy Faculty of Science > Research Groups > Chemistry of Life Processes Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry Faculty of Science > Research Groups > Energy Materials Laboratory Faculty of Science > Research Groups > Centre for Photonics and Quantum Science
Depositing User:	LivePure Connector
Date Deposited:	02 Sep 2019 15:36
Last Modified:	29 Jun 2023 14:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/72085
DOI:	10.1021/jacs.9b06858

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