Electronic coupling between azurin and gold at different protein/substrate orientations.
By means of constrained classical molecular dynamics simulations, we have computed the structure of azurin deposited on a Au(111) surface at different possible orientations and the azimuthal forces acting on the protein at each sampled conformation. We have then evaluated the effect of the angular variation on the speed of electron tunneling between the protein redox site and the metal surface. We find that the azurin/gold electronic coupling has a strong dependence on the molecular orientation and is greatly enhanced by inclining the protein to lie as flat as possible on the surface. We discuss the implications of our results for scanning probe microscopy experiments in which tunneling currents are measured while the protein is subjected to mechanical forces exerted by the tip of the instrument.
Venkat
Anurag Setty
AS
National Research Center on nanoStructures and bioSystems at Surfaces S3 of INFM-CNR, Modena, Italy.
Corni
Stefano
S
Di Felice
Rosa
R
D016880:Anisotropy; D001400:Azurin / Q000737:chemistry* / Q000648:ultrastructure*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003198:Computer Simulation; D004581:Electronics; D006046:Gold / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011485:Protein Binding; D055672:Static Electricity; D013499:Surface Properties
D020099:Coated Materials, Biocompatible; D046911:Macromolecular Substances; D001400:Azurin; D006046:Gold