Protease Power Strokes Force Proteins to Unfold
ATP-dependent proteases degrade proteins in the cytosol of cells. Two recent articles, by Aubin-Tam et al. (2011) and Maillard et al. (2011 ), use single-molecule optical tweezers to show directly that these molecular machines use the energy derived from ATP hydrolysis to mechanically unfold and translocate its substrates into the proteolytic chamber.