Conformational flexibility of natural enzymes, characterized by marginal stability, displays functional variations. In this work, we uncovered that artificial DNAzymes made of G-quadruplex (GQ)-hemin complexes also display this marginal stability phenomenon. Through single-molecule fluorescent MT-HILO (Magnetic Tweezers coupled with Highly Inclined and Laminated Optical sheet), we recorded the highest peroxidase activity among all known natural or artificial enzymes when the GQ mechanophore inside the DNAzymes was destabilized by an external force. We name enzymes with such force-responsive marginal stability "mechanozymes" to reflect the mechanical modulation of enzymatic activities. To set the stage for mechanical modulation on mechanozymes beyond the single-molecule level, ultrasonication was applied to enhance the catalytic function of a large ensemble of mechanozymes by weakening their GQ mechanophore structures. This work not only established marginal stability in artificial enzymes for the first time, but it also provided unprecedented mechanical modulation on catalytic activities, both of which are expected to have profound ramifications for catalysis exploited across the fields of chemistry and biosciences.
Ji et al. (Mon,) studied this question.