POSSIBLE USE OF DNAS IN SINGLE MOLECULE FORCE SPECTROSCOPY TO PROBE SINGLE PROTEIN UNFOLDING SIGNATURES

Abstract

Using atomic force microscope (AFM) to characterize single protein mechanics has certain limitations in terms of obtaining and recognizing single protein unfolding signals. This led us to develop a new approach through using DNA molecules as markers to probe the unfolding of our proteins. One of the basic protein parameters that can be extracted is the unfolding structure. We used AFM and Magnetic Tweezers to study Alpha-Catenin unfolding, with the former giving poorer results. We aim to couple DNA micromechanics and streptavidin-biotin interaction specificity to more unambiguously identify protein signals. We provided a working protocol to immobilize DNA for AFM manipulation. There is a stable DNA overstretching force range of 50 - 70 pN and a clear force plateau extension of ~ 50% of the fabricated DNA contour length, which can provide the two important marker parameters for protein identification.