In situ surface adsorption of the protein C hordein using atomic force microscopy

The surface adsorption of the rodlike protein C hordein has been directly i maged in the earliest stages of the process using atomic force microscopy. In a good solvent, 100 mM acetic acid, surface adsorption is marginally fav ored over desorption. However, a slight reduction in the concentration of t he acetic acid leads to a marked increase in surface adsorption. The free s urface is progressively covered to a single molecule thickness, with the mo lecule lying flat on the surface. Comparable in situ experiments on a hydro phobic surface, graphite, show that the protein- protein interaction domina tes the surface adsorption on the hydrophilic surface.