A Designer Protein That Wards Off The Aids VirusJohn Carey
In the mid-1990s, biologist Peter S. Kim discovered how the AIDS virus makes one key move during its deadly attack--and now he has come up with some promising defenses. In the Jan. 12 Science, he reports on findings that could result in new anti-HIV drugs, and even a possible vaccine.
Kim's work revealed that when HIV encounters a vulnerable cell, it shoots a molecular "harpoon" into the victim's membrane. The harpoon molecule, called GP41, then snaps back into a hairpin shape, drawing the virus into contact with the cell's membrane and allowing HIV's genes to enter the cell.
After elucidating the three-dimensional shape of the hairpin, Kim and his colleagues at Massachusetts Institute of Technology sought ways to block the virus' entry. One of their most promising schemes is reported in Science. The group has designed a protein, dubbed 5-Helix, that binds tightly to one end of GP41. As a result, it prevents the hairpin from forming--and blocks infection. It's effective against many strains of HIV, and at low concentrations. "We were pleased with how well it worked," says Kim, incoming vice-president for R&D at Merck & Co.
The findings also provide new strategies for vaccine development, says Kim. If people were immunized with the right bits of GP41, their immune systems might make antibodies that work just like the 5-Helix protein to prevent infection.