Single Molecule Studies of Enzyme Functions
The Lee lab develops ingle molecule spectroscopic/microscopic methods and applies them to the study of enzyme functions. Methods of interest include single molecule fluorescence resonance energy transfer, precise localization of macromolecules by fluorescence and light scattering, single photon correlation spectroscopy, and optical trapping. Enzymes of interest include the ribosome and tRNA synthetases.
Single molecule spectroscopy/microscopy provides ways to monitor sub-population dynamics, thereby yielding valuable information complementing ensemble measurements. High sensitivity imaging devices and several innovative signal processing techniques have boosted popularity of single molecule methods in many fields of science and engineering. A few recent additions of single molecule methods to the field of biophysics include single molecule fluorescence resonance energy transfer, nanometer (co)localization of single fluorophores, rotational and translational motion tracking of single particles, and single molecule manipulation with optical or magnetic tweezers.
Studying dynamics of molecules is essential to understand mechanisms of many important enzymatic catalyses. Studying dynamics of asynchronously moving molecules through a multi-step enzymatic reaction requires capability of monitoring sub-population dynamics which can be efficiently achieved with various single molecule methods. My research program focuses on the dynamics of molecules involved in several slow and complex enzymatic processes to understand what roles dynamics of molecules play in the processes - e.g. what are the implications of specific shapes and sizes of an enzyme and a substrate in an enzymatic process. Enzymatic processes of interest include i) translation by the ribosome, ii) non-homologous end-joining of double strand DNA breakage, and iii) tRNA charging by tRNA synthetase. Various single molecule imaging techniques and optical tweezers are utilized to probe and control the dynamics of the molecules involved in the proposed systems. My research program is very much interdisciplinary across physical chemistry, physics, biochemistry, molecular/structural/cellular biology, and nanoscale science/engineering. The goal is to provide i) novel insights into the link between the mechanisms of complex cellular machineries and the fundamental laws of dynamics, and ii) efficient single molecule methods to study and control complex enzymatic reactions.