Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 26: Frontiers of Electronic-Structure Theory: Focus on the Interface Challenge III (joint session O/CPP/DS/TT)
TT 26.5: Talk
Tuesday, April 2, 2019, 11:45–12:00, H9
Electronic Conduction in Metal Junctions with Multi-Heme Proteins — •Zdenek Futera1, Xiuyun Jiang1, Jan Elsner2, and Jochen Blumberger1,3 — 1Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom — 2University of Cambridge, Robinson College, Grange Road, Cambridge CB3 9AN, United Kingdom — 3Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2 a, D-85748, Garching, Germany
Multi-heme proteins such as STC or MtrF are membrane proteins facilitating long-range electron transfer (ET) across cell membrane in metal-reducing bacteria. We have used classical molecular dynamics (MD) together with electronic-structure calculations based on density functional theory (DFT) to show that in native environment the conducted electrons are transferred by incoherent hopping between the heme cofactors. However, recent experimental measurements of current-voltage (I-V) curves suggested that the ET mechanism changes to coherent electron tunneling in vacuum when the protein is electronically coupled with metal electrodes. To investigate such conditions, we performed MD simulations in accurate gold/protein interaction force field to identify adsorption of STC and MtrF between two gold electrodes. By large-scale DFT calculations of the whole interfacial structure we identified the conduction channels formed predominantly by delocalized heme iron states. Finally, we apply Landauer formalism to compute I-V curves on STC junction using the DFT electronic states corrected for band alignment and discuss the ET mechanism.