Mug Shot of a Virus

Retroviruses are infectious agents that reproduce by implanting their genetic material into a host cell's DNA.  The virus responsible for AIDS is a retrovirus, as is the virus - shown above - that causes leukemia.

Researchers have known that retroviruses sneak their way into a cell by using a special protein complex on their surface, but the exact shape of this chemical picklock had proven difficult to characterize.

Deborah Fass of the Weizmann Institute in Israel and her colleagues have used electron microscopy to take very detailed 3D pictures of the outer envelope of a retrovirus.  The process involved quick-freezing the viruses in liquid ethane and then capturing snapshots from various angles.

"After years of trying to imagine how the pieces fit together, suddenly we had the real structure right in front of us," Fass said. "Some aspects of it looked familiar, but others were completely unanticipated."

Understanding the protein structures of retroviruses may lead to ways to lock them out of cells.  This work appeared in the 29 March issue of the Proceedings of the National Academy of Sciences.

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-- LiveScience Staff

Credit: Weizmann Institute of Science