We show that activated Collagenase (MMP-1) is an ATP-independent motor enzyme driven by the proteolysis of its substrate, collagen. Inactivation of the enzyme by a single amino acid residue substitution in the active center halts the motor activity without noticeable effect on unbiased diffusion. Monte Carlo simulations using a model similar to a “burnt bridge” Brownian ratchet accurately describe our experimental results and previous observations on kinetics of collagen digestion.
MMP-1 is the first example of an ATP-independent extracellular molecular motor. The biological implications of MMP-1 acting as a molecular ratchet tethered to the cell surface are of considerable interest, suggesting new mechanisms for its role in the tissue remodeling and cell - matrix interaction.
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