Which Multi-Heme Protein Complex Transfers Electrons More Efficiently? Comparing MtrCAB from Shewanella with OmcS from Geobacter

Jiang, Xiuyun, Van Wonderen, Jessica, Butt, Julea, Edwards, Marcus J., Clarke, Tom and Blumberger, Jochen (2020) Which Multi-Heme Protein Complex Transfers Electrons More Efficiently? Comparing MtrCAB from Shewanella with OmcS from Geobacter. The Journal of Physical Chemistry Letters, 11 (21). 9421–9425. ISSN 1948-7185

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Abstract

Microbial nanowires are fascinating biological structures allowing bacteria to transport electrons over micrometers for reduction of extracellular substrates. It was recently established that the nanowires of both Shewanella and Geobacter are made of multi-heme proteins, but while Shewanella employs the 20-heme protein complex MtrCAB, Geobacter uses a redox polymer made of the hexa-heme protein OmcS, begging the question which protein architecture is more efficient in terms of long-range electron transfer. Using a multiscale computational approach we find that OmcS supports electron flows about an order of magnitude higher than MtrCAB due to larger heme-heme electronic couplings and better insulation of hemes from the solvent. We show that heme side chains are an essential structural element in both protein complexes accelerating rate-limiting electron tunnelling steps up to 1000-fold. Our results imply that the alternating stacked/T-shaped heme arrangement present in both protein complexes may be an evolutionarily convergent design principle permitting efficient electron transfer over very long distances.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
Depositing User: LivePure Connector
Date Deposited: 20 Oct 2020 23:58
Last Modified: 24 Nov 2020 01:45
URI: https://ueaeprints.uea.ac.uk/id/eprint/77373
DOI: 10.1021/acs.jpclett.0c02842

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