X-Ray Laser Reveals Structure of Key Sleeping Sickness Enzyme

An international team of scientists, using the world’s most powerful X-ray laser, has revealed the three-dimensional structure of a key enzyme that contributes to the pathogenicity of the single-celled parasite that causes African trypanosomiasis (or sleeping sickness) in humans. With the elucidation of the 3D structure of the cathepsin B enzyme, it should be possible to design new drugs to inhibit the parasite (Trypanosoma brucei) that causes sleeping sickness, leaving the infected human unharmed. The research team, including several Arizona State University (ASU) scientists, was led by the German Electron Synchrotron (DESY) scientist Dr. Henry Chapman from the Center of Free-Electron Laser Science (CFEL), professor Christian Betzel from the University of Hamburg and Dr. Lars Redecke from the SIAS joint Junior Research Group at the Universities of Hamburg and Lübeck. The team reported its findings on November 29, 2012 in Science. "This is the first new biological structure solved with a free-electron laser," said Dr. Chapman of the development. "These images of an enzyme, which is a drug target for sleeping sickness, are the first results from our new ‘diffract-then-destroy’ snapshot X-ray laser method to show new biological structures which have not been seen before,” explained Dr. John Spence, ASU Regents’ Professor of Physics. “The work was led by the DESY group and used the Linac Coherent Light Source at the U.S. Department of Energy’s SLAC National Accelerator Laboratory." Transferred to its mammalian host by the bite of the tsetse fly, the effects of the parasite are almost always fatal if treatment is not received. The sleeping sickness parasite threatens more than 60 million people in sub-Saharan Africa and annually kills an estimated 30,000 people.
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