Nuclear Physics(DNP)
Physique nucléaire (DPN)

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Nancy FORDE
UC Berkeley

Using Optical Tweezers to Study Single-Molecule Reactions in Real Time*

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The ability to exert force on single molecules offers an experimental means to probe mechanical processes and to see beyond ensemble-averaged behaviours. Optical tweezers, which use a focused laser beam to manipulate micron-sized refractive particles with nanometer precision, allow us to exert and detect forces on the picoNewton scale. By attaching molecules of interest to these particles, we can determine molecular response to applied mechanical force. In this talk, I will discuss our recent experiments that take advantage of previously characterized elastic properties of DNA in order to follow the movement of RNA polymerase along DNA in real time. RNA polymerase is a molecular motor that catalyzes synthesis of an RNA polymer chain, converting chemical energy into mechanical force causing directed movement along the DNA template. By studying this transcription reaction by single molecules of RNA polymerase, and applying a mechanical force to assist or oppose translocation along DNA, we have been able to follow, and in some cases alter, the reaction kinetics in real time.

*In collaboration with C. Bustamante1,2,3 and D. Izhaky1, 1Howard Hughes Medical Institute, 2Department of Molecular and Cell Biology, and 3Department of Physics, University of California, Berkeley.

*In collabaration with: D Izhaky UC Berkeley,C Bustamante UC Berkeley.