RESEARCH Areas

Single Molecule Techniques

Single molecule manipulation and observation techniques provide an unparalleled and dramatic means to study biological reactions. In general, these approaches permit direct observation, in real time, of the dynamic properties of individual molecules that would otherwise be lost in the averaging process using conventional ensemble assays. In addition, for DNA motor proteins the potential exists to measure the step size of the motor; to determine the motor's energy consumption (i.e., the number of ATP molecules consumed per catalytic cycle), to find the rate-limiting transitions in the chemomechanical cycle and, to identify steps in a reaction that are sensitive to load by analyzing the force-dependence of enzymatic rates.

The primary, real-time single molecule technique we use combines optical tweezers with video, fluorescence microscopy. This system was originally developed by me while I was a postdoctoral fellow in Steve Kowalczykowski's lab at UC Davis. The system is designed to view DNA motor proteins in action.
The second technique, atomic force microscopy, is used primarily to monitor forces associated with DNA helicase translocation and unwinding.

>> Optical tweezers
>> Atomic Force Microscopy