They may never win an Oscar, but scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have developed techniques for creating accurate movies of biological and chemical molecules, a feat only theorized up until now.
Biological and organic molecules in solution are far more complex than the standard crystalline structures of salt or metals since they are constantly moving and changing over time. These motions have not yet been seen directly, but scientists using the high intensity x-rays at the Advanced Photon Source have measured images that are “blurred” by these motions and have used them to create more accurate movies of molecular motions.
Computer simulations are currently the only way to visualize molecular motions in solution, but researchers have not had a means to check the accuracy of these simulations for complex molecules. For the first time, scientists can see the movements first hand and compare them to their theoretical counterparts.
“The blurring that we see in our solution x-ray patterns are remarkably sensitive to the type of the molecular motion,” senior chemist David Tiede said. “For the first time, we are able to test the accuracy of the simulation and change it to fit data better. Without it, we had no way of knowing how accurate the models were.”
Tiede hopes an improved accuracy in molecular modeling will give insights into the structure and behavior of the molecules. Collaborators at the National Institutes of Health have used this approach to help determine structures of important biological molecules.
Tiede and his collaborators also plan to examine how a structure reacts to an outside stimulus. By using a laser to excite the atoms, he will create a movie that shows how the molecule reacts to the initial laser pulse and also how it returns to a stable condition.
“We hope to establish between ‘good’ and ‘bad’ molecular actors in important chemical processes like photosynthesis, solar energy and catalysts,” Tiede said. “Once we see that, we can make these processes work better.”
Source: Argonne National Laboratory
Related stories:
Researchers identify photosynthetic dimmer switch
In a study of the molecular mechanisms by which plants protect themselves from oxidation damage should they absorb too much sunlight during photosynthesis, a team of researchers has discovered a molecular “dimmer switch” that helps control the flow of solar energy moving through the system of light harvesting proteins. This discovery holds important implications for the future design of artificial photosynthesis systems that could provide the world with a sustainable and secure source of energy.
FSU researchers make observing cell functions easier
Now that the genome (DNA) of humans and many other organisms have been sequenced, biologists are turning their attention to discovering how the many thousands of structural and control genes -- the “worker bees” of living cells that can turn genes on and off -- function.
Previously unseen switch regulates breast cancer response to estrogen
A tiny modification called methylation on estrogen receptors prolongs the life of these growth-driving molecules in breast cancer cells, according to research by scientists at Emory University's Winship Cancer Institute. The results are published in the May 9, 2008 issue of the journal
Molecular Cell.
Researchers Observe Hydrogen-Bond Exchange
Hydrogen bonds are quite small, on the level of a few angstroms. They can also be passed between two different molecules very quickly, at speeds of tens of times per second. But in spite of these properties, researchers have recently observed hydrogen-bond exchange taking place in real-time.
Molecular espionage shows a single HIV enzyme's many tasks
Using ingenious molecular espionage, scientists have found how a single key enzyme, seemingly the Swiss army knife in HIV's toolbox, differentiates and dynamically binds both DNA and RNA as part of the virus' fierce attack on host cells. The work is described this week in the journal
Nature.
Researchers synthesize compound to flush HIV out of hiding
Any hunter will tell you that when your quarry goes into hiding, you have to flush it out to get a good shot at it. Such is the case with HIV, the virus that causes AIDS.
Researchers explain how birds navigate
It has long been known that birds and many other animals including turtles, salamanders and lobsters, use the Earth’s magnetic field to navigate, but the nature of their global positioning systems (GPS) has not been completely understood.
Newly refined antibody therapy may be potent treatment for autoimmune diseases
An old, fickle therapy for a variety of autoimmune diseases is getting a makeover, thanks to a decade-long investigation by Rockefeller University researchers. The original treatment, called intravenous immunoglobulin or IVIG, is an amalgam of specific antibodies made from the pooled blood plasma of thousands of healthy donors.