There are basically two breakthrough developments here; in order to obtain measurements accurate to 1/10th of a nanometer the light source, a laser
beam in this case, had to be stabilized. Essentially, all of the external optics of the microscope were placed in a sealed box, and all the air was
replaced with He gas. This provides a refractive index that’s much closer to a vacuum than air is.
The second major breakthrough here is the optical trap. While I can’t delve into the details, as it’s not my area of expertise, this particular
optical trap maintains a constant force, which simplifies the observation of such slight motions.
Apparently, this new technique has actually helped resolved some of the fundamental issues re: the mechanism of RNA polymerase that scientists have
debated for years. No doubt other huge gains in knowledge will result from this.
Mostly science makes progress in baby steps. Occasionally, new technologies such as this are conceived that make progress in one giant leap. Great
job!
www.sciencedaily.com
In a second paper published in the Nov. 8 online issue of the journal Physical Review Letters, the scientists offer a detailed description of their
novel device, an advanced version of the "optical trap," which uses infrared light to trap and control the forces on a functional protein, allowing
researchers to monitor the molecule's every move in real time.
"In the Nature experiment, we carried out the highest-resolution measurement ever made of an individual protein," says Steven Block, professor of
applied physics and of biological sciences. "We obtained measurements accurate to one angstrom, or one-tenth of a nanometer. That's a distance
equivalent to the diameter of a single hydrogen atom, and about 10 times finer than any previous such measurement."
The development of an ultra-stable optical trapping system with angstrom resolution is "a major advance," says Charles Yanofsky, the Morris
Herzstein Professor of Biological Sciences at Stanford and a pioneer of modern molecular genetics. The new device is like "adding movies to stills in
understanding enzyme action," he says.
Please visit the link provided for the complete story.
As one of the researchers mentioned this is going to blow the world of molecular biophysics wide open… several other fields, including proteomics,
and other protein related disciplines.
Until now for the most part motion in proteins has been inferred by trapping protein in various ‘states’ with different crystal structures and
calculating likely trajectories of atoms. This is a whole new ball game though. Now were talking about working, functional proteins, being observed
performing there work. We now have the capability to actually visualize biological molecular machines at the atomic level. I would have never believed
it 10 years ago.
I found the news release at Science Daily, but there are two peer reviewed articles available. The articles are subscription only, but I'll have them
downloaded later. U2U me if you want a copy… we can make arrangements.
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[edit on 18-11-2005 by asala]