Scientists devise method to study membrane proteins

Apr 14, 2004

Scientists at the University of Virginia Health System have come up with a protocol to extract proteins from membranes by using chemicals that allow them to be reversibly folded and refolded. The proteins can then be studied using crystallography or nuclear magnetic resonance imaging. Their work is detailed in the March 23 issue of the “Proceedings of the National Academy of Sciences” (PNAS) and also on the cover of the journal. The paper can be found on the web at: http://www.pnas.org/cgi/content/full/101/12/4065.

“The majority of drugs on the market today are effective because they work on membrane proteins, but our basic knowledge about these proteins lags far behind that of water-soluble proteins,” said Lukas Tamm, professor of molecular physiology and biological physics at U.Va. “We need to develop systems to get enough of these membrane proteins expressed in a cell culture so we can measure their thermodynamic, or energetic, stability,” Tamm said. “This is of practical interest in designing proteins for therapeutic applications because the proteins need to be kept around for a long time. This protocol developed at U.Va. shows for the first time that these proteins can be taken out of their membrane environment and put back in without losing function,” Tamm said. “We also found that the thermodynamic stability, or energy difference, between the folded and unfolded form of membrane proteins depends on the strength of the membrane “rubber band” that the proteins sit in. This energy difference can be predicted, one key variable in the drug discovery process.”

In a commentary on the findings, also in the March 23 issue of PNAS, James Bowie, a professor with the Molecular Biology Institute at the University of California, Los Angeles, wrote that “the new work opens another door to a more quantitative description of the energetics protein-protein and protein-lipid interactions in the (membrane) bilayer… We are finally beginning to obtain quantitative information about membrane protein structure.”

Working with U.Va. colleague Heedeok Hong, Tamm used an aqueous (water) system and a compound called urea, that unravels proteins, to carry out folding studies on a membrane protein of the Escherichia coli bacterium called OmpA. Tamm and Hong demonstrated that the folding of OmpA into the lipid bilayers of a membrane is a reversible, two-state process. They also demonstrated that elastic forces in bilayers, such as curvature stress, can affect the folding of membrane proteins.


Explore further: Berkeley algorithms help researchers understand dark energy

add to favorites email to friend print save as pdf

Related Stories

LiquidPiston unveils quiet X Mini engine prototype

3 hours ago

LiquidPiston has a new X Mini engine which is a small 70 cubic centimeter gasoline powered "prototype. This is a quiet, four-stroke engine with near-zero vibration. The company said it can bring improvements ...

Rare new species of plant: Stachys caroliniana

3 hours ago

The exclusive club of explorers who have discovered a rare new species of life isn't restricted to globetrotters traveling to remote locations like the Amazon rainforests, Madagascar or the woodlands of the ...

New terahertz device could strengthen security

4 hours ago

We are all familiar with the hassles that accompany air travel. We shuffle through long lines, remove our shoes, and carry liquids in regulation-sized tubes. And even after all the effort, we still wonder if these procedures ...

European space plane set for February launch

4 hours ago

Europe's first-ever "space plane" will be launched on February 11 next year, rocket firm Arianespace said Friday after a three-month delay to fine-tune the mission flight plan.

Recommended for you

Tiny magnetic sensor deemed attractive

15 hours ago

Ultra-sensitive magnetic sensor technology pioneered at PML may soon be commercialized for a host of applications from detection of unexploded bombs and underground pipes to geophysical surveying and perhaps ...

Beams come knocking on the LHC's door

15 hours ago

Over the weekend, proton beams came knocking on the Large Hadron Collider's (LHC) door. Shooting from the Super Proton Synchrotron (SPS) and into the two LHC injection lines, the proton beams were stopped ...

Climate control in termite mounds

17 hours ago

When they make their way into homes, some species of termites can be destructive pests. Their fungus-harvesting relatives in Africa and Asia, however, are known for their construction prowess, collectively ...

The secret of dragonflies' flight

17 hours ago

Dragonflies can easily right themselves and maneuver tight turns while flying. Each of their four wings is controlled by separate muscles, giving them exquisite control over their flight.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.