Mechanistic Origin of Protein Flexibility of Ubiquitin Family Proteins
Here we investigate the mechanistic origins of protein malleability. We develop a methodology using Single-Molecule Force spectroscopy (SMFS), fluorescence spectroscopy and circular dichroism to probe the native and transition states of Ubiquitin and small ubiquitin-related modifier (SUMO2), to get insights into the protein dynamics and mechanical resistance. Both SUMO2 and Ubiquitin have mechanical clamp which serve as a major resistor to force in SMFS experiments. But we show that the core of the protein actually couples to the clamp and determines its overall malleability. And to top it off we look at the interactions which determine the core flexibility in both the proteins.