Wesley Wong of the Rowland Institute at Harvard and his colleagues have developed a unique optical tweezers system that uses a combination of interference imaging, light modulation and custom software algorithms to achieve the necessary resolution and stability to watch proteins fold. This system, which employs already-existing optical technology components, utilizes 3-D video tracking to measure the lengths of short molecular tethers with angstrom resolution (less than 1 billionth of a meter) and active feedback control for a force stability of femtoNewtons (10^-15 Newtons). Fluctuations can be glimpsed at rates faster than 100,000 frames per second -- all with inexpensive video-imaging. The act of protein folding is quantified by measuring the end-to-end distance of a single molecule while the strength of the tweezers' grip is varied.
The Wong group uses optical tweezers to study the behavior of single molecules under force in order to reveal the nanoscopic workings of biological systems. Together with their collaborators, they have used this approach to expose the molecular feedback mechanism behind the regulation of blood clotting and to determine the dynamic mechanical properties of spectrin, a structural molecule la
|Contact: Angela Stark|
Optical Society of America