Single-molecule biophysics. Our laboratory employs microscopy techniques in conjunction with magnetic tweezers to study reactions catalyzed by enzymes engaged in DNA metabolism one-at-a-time. Employing single-molecule techniques we can circumvent ensemble averaging, thereby being able to the investigate sequences of molecular events, conformation dynamics, and protein-protein interactions. We are particularly interested in helicases because individuals with mutations in these motor proteins are susceptible to cancer.
DNA mechanical properties. During DNA metabolism this biopolymer is stretched, bended and/or twisted resulting in conformations and deformations crucial in gene regulation. An ongoing project explores new DNA substrates that mimic some of these forms using single-molecule force spectroscopy. We are also studying substrates that can provide information about the elastic properties and energetics of the compacted forms of the DNA of prokaryotic organisms.
Development of fluorescence essays. In this project we are testing strategies to alter the photophysical properties of adenine and tryptophan (Trp) in order to enhance their emission properties. Recently, we increased the room temperature phosphorescence of the Trp residue in proteins. This was accomplished by forcing the interaction between molecular perturbers and Trp through the formation of ternary cyclodextrin inclusions complexes. This finding is important because phosphorescence lifetime measurements will allow studies of slow molecular events such as protein conformation dynamics.
