Doctor Piotr Marszalek
Mayo Foundation
Rochester, Minnesota

Tuesday, June 19, 2001
3:00 pm (CT)
3169 Beckman Institute

Abstract

In atomic force microscopy (AFM), single molecules as short as ~20 nm can be stretched vertically between a solid substrate and a miniature elastic cantilever. Since AFM employs stiff force transducers (cantilevers), it can generate large stretching forces (F > 1 nN) that are able to affect molecules' conformations. For example, such forces can mechanically unravel proteins and can trigger transitions in the sugar rings of polysaccharides. Because of its high resolution AFM can identify such mechanical events like a rupture of a single hydrogen bond in the tertiary structure of a protein or a < 1 ? change in the separation of the glycosidic oxygens upon the chair to boat transition in glucose. In addition, mechanical fingerprints produced upon stretching molecules in AFM may be used to reveal their chemical identity.