Dresden 2014 – wissenschaftliches Programm

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PV: Plenarvorträge

PV XVIII

PV XVIII: Plenarvortrag

Freitag, 4. April 2014, 08:30–09:15, HSZ 01

Optical Tweezers: Gene Regulation, Studied One Molecule at a Time — •Steven Block — Depts. of Applied Physics and Biology, Stanford University, Stanford CA, U.S.A.

Technical advances have led to the birth a new field, dubbed "single molecule biophysics." Single-molecule methods can record molecular characteristics that are otherwise obscured by traditional, ensemble-based approaches, revealing rich new behaviors. An entire arsenal of techniques with single-molecule sensitivity has now been developed. Prominent among these technologies has been the optical trap, or "optical tweezers," which is based on radiation pressure from an infrared laser. When combined with suitable in vitro assays for function, optical trapping microscopes can measure molecular properties with exquisite precision, down the atomic level (currently achieving a resolution of ~1 angstrom in a bandwidth of ~100 Hz), while exerting controlled forces in the piconewton (pN) range. Ultrasensitive systems for measuring force and displacement permit the nanomechanical properties of single molecules to be explored noninvasively. Among the notable successes for optical traps have been measurements of the fundamental steps (and forces) generated by motor proteins and processive nucleic acid enzymes, the strengths of noncovalent bonds between proteins, and the kinetics and energetics of folding in biopolymers, including DNA and RNA. This talk will give special attention to recent success in following the co-transcriptional folding of a nascent RNA molecule in real time as it is synthesized by RNA polymerase, and how its folding can regulate gene expression.