Optical Tweezers: Gene Regulation, Studied One Molecule at a Time
Advances have led to the new field of single molecule biophysics. Single-molecule techniques can record characteristics that are obscured by traditional biochemical approaches, revealing behaviors of individual biomolecules. Prominent among the techniques is the laser-based optical trap, or ‘optical tweezers,’ which uses radiation pressure. Optical traps can now measure biomolecular properties with a precision down the atomic level—achieving a resolution of 1 angstrom over a bandwidth of 100 Hz—while exerting controlled forces in the piconewton range. Among the successes for optical traps have been measurements of the molecular steps produced by motor proteins (for example, kinesin and myosin) and by processive nucleic-acid enzymes (for example, RNA polymerase), determinations of the strengths of noncovalent bonds between proteins, and studies of the energetics and kinetics of structure formation by nucleic acids. Optical trapping instruments have been particularly useful in mapping the energy landscapes for folding RNA molecules. Beyond that, we’re now able to follow the cotranscriptional folding of RNA in real time, as it’s synthesized, revealing how such folding can regulate downstream genes, mediated by structured elements called riboswitches. In recent developments, optical traps have been used in conjunction with single-molecule FRET (Förster Resonance Energy Transfer) to report on the folding configurations and internal degrees of freedom in biomolecules.
Professor Block holds the Ascherman Chair in the Depts. of Applied Physics and Biology at Stanford. He's best-known as a founder of the field known as " single-molecule biophysics." Block holds degrees from Oxford and Caltech and served as faculty at the Rowland Institute and Harvard, then Princeton, prior to joining Stanford in 1999. Block is a member of the National Academy of Sciences, the American Academy of Arts & Sciences, and is a Fellow of the AAAS, the APS, and the BPS. His research lies at the interface of physics and biology, particularly in the study of biomolecular motors, including kinesin and RNA polymerase, and the folding of nucleic acid-based structures. His group pioneered the use of laser-based optical traps to study the nanoscale motions of biomolecules. In what's left of his spare time, he enjoys skiing and playing bluegrass music on the banjo and mandolin.
Tuesday, August 21 at 9:30am to 11:00am
Edgar A. Brown University Union, Student Senate Chambers
602 University Union Clemson, SC