Proteins are literally the movers and the shakers of the intracellular world. If DNA is the film director, then they are the actors. And much can be learned about cell function and dysfunction by watching proteins on the move.
Until now, scientists have only been able to see this process indirectly. Now researchers at Vanderbilt University in Nashville, Tenn., have come up with a promising new technique that uses a scanning transmission electron microscope (STEM) to view proteins tagged with gold nanoparticles in whole, intact cells.
Determining the locations of proteins in an intact cell could help researchers study cancer processes, as well as understand how viruses break into healthy cells and hijack them, says Vanderbilt University assistant professor of physiology and biophysics Niels de Jonge, who will be presenting his team's results at the AVS Symposium in Nashville, Tenn., held Oct. 30 Nov. 4. The benefits of the new technique could extend beyond biology to the energy and materials sciences, too, suggests de Jonge, giving researchers tools that could help them design better car batteries, for example.
Modern methods of studying protein interactions have limitations. Optical microscopes can capture sweeping vistas of whole, live cells; but though state-of-the-art techniques allow these microscopes to achieve a resolution of just 50 nanometers, the devices are not sensitive enough to zoom in for a close-up on individual proteins, which are only a few nanometers across. Transmission electron microscopes (TEM) can resolve the locations of individual proteins, but at the expense of the whole picture: the cell must be frozen, cut into pieces, and placed in a vacuum in order to be imaged.
To detect proteins in a whole, undamaged cell, the Vanderbilt scientists took advantage of a STEM analysis technique called annular dark-field (ADF) imaging, which involves collecting electrons from a ring around the STEM's electro
|Contact: Catherine Meyers|
American Institute of Physics