Single-particle tracking of DNA origami-enzyme conjugates in the presence of their substrate*

Recent experiments have shown that enzymes can exhibit enhanced diffusion in the presence of their chemical substrates. The fundamental physics governing the enhanced diffusion of enzymes, however, is still unknown. Therefore, new model experimental systems are needed. In this talk, I will describe our efforts to develop a suite of programmable active particles using DNA origami to test hypotheses for the enhanced diffusion of enzymes. In particular, we conjugate enzymes to the surface of DNA origami, in user-prescribed locations and patterns, and look for changes to their diffusion using total internal reflection fluorescence microscopy and single-particle tracking. With the conjugate trajectories in hand, we then calculate the mean squared displacement and the jump-length statistics to infer the diffusion coefficient and whether or not the motion is entirely Brownian. By exploiting the programmability and site-addressability of DNA origami, we anticipate that these experiments will help to shed light on the nature of enzyme motility.