New method to describe the HIV sugar barrier

scientists at the Scripps Institute and Los Alamos National Laboratory have developed a new way to map out unprecedented details of the smooth sugar molecules of HIV. These molecules protect HIV from the immune system. The paper was published recently in the Proceedings of the National Academy of Sciences.
these maps will give researchers a more complete picture of why antibodies respond to certain points of the virus and not to others, and may lead to the development of new vaccines for the most vulnerable and accessible sites of HIV and other viruses.
these sugar molecules, or "polysaccharies," are loose, viscous and act as shields because antibodies are difficult to grasp and block from entering the protein's surface. HIV and many other viruses, including the new coronavirus, form these shields on the outermost prickly protein.
we now have a way to capture the complete structure of these ever-changing polysaccharid barriers, which largely determines where antibodies can but cannot bind to viruses like HIV," he said. Zachary Berndsen, a postdoctoral student at the Scripps Institute and lead author of the study, said.
make these sugary molecules anti-antibody-resistant and prevent researchers from capturing them using traditional atomic-scale imaging techniques. In the new study, scientists developed a technique that maps these elusive molecules to the surface of the HIV python (Env) in detail for the first time.
combined cryogenic electron microscopes with sophisticated computer modeling and molecular recognition techniques. Cryogenic electron microscopes rely on thousands of individual snapshots to create a clear image, so highly flexible molecules like polysaccharies can only appear in fuzzy form if they appear. But by combining cryogenic electron microscopes with other techniques, researchers were able to recover lost polysaccharose signals and use them to map vulnerable bits on Env's surface.
new combination approach reveals the structure and extremely detailed dynamic properties of the HIV polysaccharose barrier and helps the team better understand how these complex dynamics affect the characteristics observed in cryogenic electronscopes. The team observed that individual polysaccharies did not swing randomly on the surface of the hedgehog protein, as previously thought, but rather gathered in a clump of "shrubs". (Source: Lu Yi, China Science Journal)
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