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WEST LAFAYETTE, Ind. - A detailed look at one of nature's smallest motors is providing scientists with new insights on how some viruses package their genetic material and reveals a new type of biological motor system.
Scientists at Purdue University and the University of Minnesota have solved the three-dimensional structure of the central component of a biological "motor" that powers the DNA packaging system in a virus, providing scientists with their first glimpse of such a motor system.
The study describes atom-by-atom how the core of the tiny motor, just millionths of a millimeter in size, is constructed and suggests how it works to translocate, or pack, long stretches of the virus' genetic material into its outer shell during the process of viral replication.
Details appear in the Dec. 7 issue of the scientific journal Nature.
"This study provides the first knowledge of a DNA packaging motor," says Michael Rossmann, Hanley Distinguished Professor of Biological Sciences at Purdue. "Though other motor systems have been studied in biology, this is the first motor known to translocate genetic material."
Viruses are essentially a simple parasite consisting only of an envelope that contains the genetic material ready for transportation from one host to another. They can reproduce only after infecting a host cell. Once inside a cell, the virus manipulates the cell's machinery to produce all the necessary components, including genetic material, to assemble new viruses. It is here that the biological motor is needed to fill newly assembled envelopes with their genetic material, Rossmann says. The new viruses are then released from the host cell and are free to infect other cells.