ATOMIC-FORCE MICROSCOPY OF CHOLERA-TOXIN B-OLIGOMERS BOUND TO BILAYERS OF BIOLOGICALLY RELEVANT LIPIDS

Cholera toxin B-oligomer was imaged by atomic force microscopy (AFM) o n biologically relevant model membranes, such as almitoyI-2-oleoyl-sn- glycero-3-phosphoethanolamine and egg yolk phosphatidylcholine at room temperature in solution at a resolution in the range of 1 to 2 nm. In addition, two-dimensional arrays were grown directly on these model m embranes without any special treatment, and were also imaged by AFM. T hese results demonstrate the ability of AFM for imaging membrane prote ins at high resolution without the need of chemical cross-linking, eit her within the membrane or to the substratum.