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The Pyrenean ibex, an impressive mountain goat that lived in the central Pyrenees in Spain, went extinct in 2000. But a...
Tight budgets are forcing NASA to consider turning off one or more planetary science projects that have completed their...
Ebola is not a stranger to West Africa—an outbreak in the 1990s killed chimpanzees and sickened one researcher. But the...
In an as-yet-unpublished report, an international panel of geoscientists has concluded that a pair of deadly...
Tropical disease experts tried and failed before to eradicate yaws, a rare disfiguring disease of poor countries. Now,...
Since 2002, researchers have reported that agricultural communities in the hot and humid Pacific Coast of Central...
Balkan endemic kidney disease surfaced in the 1950s and for decades defied attempts to finger the cause. It occurred...
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Detailed Look at Molecular Railway Ties
23 December 1997 7:00 pm
WASHINGTON, D.C.--Biophysicists have solved the structure of a protein that makes up the cell's internal rail system, transporting everything from proteins to DNA. The new structure, unveiled here last week at a meeting of the American Society for Cell Biology, may help researchers design better anticancer drugs and fungicides.
The protein, called tubulin, aligns into long tubular filaments that shuttle molecules through the cell and are essential for guiding chromosomes during the line dance of cell division. For years, attempts to use x-ray crystallography to determine tubulin's structure failed because the protein refused to crystallize properly.
Taking another tack, Kenneth Downing and Eva Nogales of the Lawrence Berkeley National Laboratory in California crafted a tubulin sheet just one molecule thick--a simpler task that allowed them to use an alternative technique called electron beam crystallography. They bounced very low energy electrons off the sheet from many different angles to compose a three-dimensional image. The tubulin structure will appear in the 8 January 1998 issue of Nature.
"It's a huge milestone in the cytoskeleton field," says Duke cell biologist Harold Erickson. The structure reveals how tubulin's two parts interlock and which amino acids appear to be crucial for the protein to latch onto other molecules. The structure also shows the binding site of taxol, an important anticancer drug that works by tossing up roadblocks on the microtubule highway. That information might allow researchers to design a family of microtubule disrupters.