Two-dimensional vectorial arrays of functional Photosystem I reaction centers have been prepared on atomically flat derivatized gold surfaces. The nature and extent of orientation were controlled by chemical modification of the surface derivative. For mercaptoacetic acid, 83% of the electron transport vectors were parallel to the surface, whereas with 2-mercaptoethanol 70% were oriented perpendicularly in the “up” position and only 2% were in the “down” position. No preferential orientation was observed with 2-dimethylaminoethanethiol.

• Received 19 March 1997

DOI:https://doi.org/10.1103/PhysRevLett.79.3294