Atomistic Modeling of Iron Oxide Nanoparticle/Nanocluster Interaction with Shewanella Oneidensis Cytochromes and Electron Transfer Kinetics

Shewanella oneidensis is a metal-reducing bacteria that is capable of reducing dissimilatory metal oxides by transferring electrons through transmembrane cytochromes. Electron transfer (ET) occurs from the interior of the cell to the exterior through the network formed by the hemes in the proteins. In this work, we use an iron oxide nanoparticle/nanocluster to represent the extracellular mineral and study its interaction with the proteins as well as the outer membrane of S. oneidensis. This work investigates the interaction of iron oxide nanoparticles/nanoclusters (NP/NC) with MtrF, an extracellular decaheme cytochrome, and the MtrCAB complex, a transmembrane protein with three subunits and 20 hemes, using a combination of all-atom molecular dynamics simulations and kinetic Monte Carlo simulations. The protein corona formation in bulk water and the corresponding ET kinetic behavior are studied. The effect of the size and curvature of NPs/NCs on protein adsorption and ET behaviors of proteins is examined. Additionally, the interaction of NP/NC with the outer membrane, composed of a lipid bilayer and multiheme cytochrome proteins, is investigated. The stability of the protein complex and ET behavior are also analyzed. This work has important applications in biotechnology.