Exerting Mechanical Force on Single Protein Molecules
Using AFM force spectroscopy one can measure physiologically relevant pN forces between an AFM tip and a biomolecule with a mean displacement resolution ofabout 0.1 nm. The last 15 years have witnessed an explosion of interest in single molecule force spectroscopy fueled by:
- new possibilities to advance in protein folding,
- possibilities to elucidate molecular mechanisms of various cellular processes, and diseases, and
- efforts to understand the nanomechanical properties of proteins, polysaccharides and DNAs in order todesign biomimetic and/or mechanically functional materials.
In this seminar, we will present several examples of our AFM force spectroscopy data. First, we will present the results of mechanical unfolding of on a recombinant protein comprising an NRR domain from mammalian Notch 1. Notch is a transmembrane cell signaling protein, and understanding its mechanical properties at the single molecule level is expected to help elucidating Notch’s role in processes relevant to embryonic development, tissue homeostasis, and some breast cancers. Second, we will concentrate on elucidating early folding events in a simple model protein from changes of molecular compliance and dissipation factors. Using such measurements, we hope in a future to provide basic understanding of early folding event. Time permitting, we will show how mechanical force can influence the rate and mechanisms of an enzymatic cleavage of a single disulfide bond embedded in a protein.