Unravelling how viruses enter cells.

A team of researchers led by Michael G. Rossman, Hanley Distinguished Professor of Biological Sciences, Purdue University, West Lafayette, Ind., has unlocked the secrets of a receptor that the common cold virus uses as an entryway to infect human cells. Their findings may help slam the door on one of the most troublesome and universal pathogens known to humans.

According to Rossman, the researchers have analyzed in atomic detail the three-dimensional structure of the part of the cellular receptor which binds to a virus that causes the majority of colds in humans. Knowing the structure of this receptor will help scientists unravel the mystery of how cold viruses enter cells, and it may suggest ways for developing drugs that prevent the common cold and other illnesses that are caused by similar viral pathogens. The receptor, called ICAM-1, is made up of a single protein and shaped somewhat like an arm divided into five sections, or domains, extending from a shoulder that penetrates the cellular membrane. Rossman's group has solved the structure of the first two domains, which are located at the "hand" end of the molecule where the virus attaches. Each cell may contain thousands of these receptors on its membrane.

ICAM-1--an acronym for intercellular adhesion molecule one--is one of many types of adhesion molecules found in multicelled organisms. As the name implies, adhesion molecules play a role in binding cells to other molecules or cells. ICAM-1 normally functions to hold infection-fighting white blood cells in place in regions of the body that have been injured or damaged...