Reproducible acquisition of Escherichia coli porin surface topographs by atomic force microscopy.

Crystalline membranes reconstituted from Escherichia coli OmpF porin and phospholipids were adsorbed to freshly cleaved mica and imaged in solution by the atomic force microscope. The extracellular as well as the periplasmic side of the porin trimers could be identified and the conditions to record topographs at 1-nm lateral and 0.1-nm vertical resolution were established.