Conformational transitions in single protein and polysaccharide molecules studied with AFM techniques

We use single molecule AFM techniques to trigger mechanical unfolding and mechanical unfolding intermediates in the immunoglobulin modules of an engineered polyprotein. Site directed mutagenesis of the immunoglobulin modules results in well defined mechanical phenotypes that are readily detectable with single molecule AFM techniques. In addition to examining the conformational changes of proteins, we can also use similar techniques to trigger chair to boat, and chair inversion transitions in the pyranose rings of single polysaccharide molecules. Our results demonstrate the use of an AFM to detect conformational changes in single molecules with a resolution similar to that of NMR or X-ray diffraction techniques