Research Seminar FRIAS Research Focus Quantum Transport - Jochen Blumbergen: Electron flow through bacterial nanowire proteins / David Leitner: Quantum energy flow and localization in molecules

Abstract Blumberger:

In my talk I will describe our recent efforts to compute the microscopic parameters determining electron transfer in a recently crystallised deca-heme protein (`bacterial nanowire') of the bacterium Shewanella Oneidensis [1], employing fragment orbital density functional theory calculations and molecular dynamics simulation. Comparison between the computed electron flux through the protein, based on sequential electron hopping between the frontier orbitals of the heme groups[2,3], and the experimental solution kinetics on a related protein complex[4] indicates good agreement. We find that electron transport along the heme nanowire is a finely tuned balancing act between the ups and downs on the free energy landscape[5] and heme-heme electronic interactions[3]. Interestingly, at the presence of a finite bias voltage applied to the ends of the protein, calculations based on electron hopping predict currents that are three orders of magnitude lower than measured in AFM experiments [5]. Possible alternative conduction mechanisms that give rise to the high currents observed in experiments will be discussed.