Scientists Snap an Image of a Piece of HIV Protein

In a groundbreaking discovery, for the first time researchers from the National Institute of Allergy and Infections Diseases (part of National Institutes of Health), Dana-Farber Cancer Institute in Boston, and The Scripps Research Institute in La Jolla have crystallized and captured an atomic-level picture of a key portion of an HIV surface protein as it looks when bound to an infection-fighting antibody. Unlike much of the constantly mutating virus, this protein component is stable and -- more importantly, say the researchers -- appears vulnerable to attack from this specific antibody, known as b12, which can broadly neutralize HIV.

This finding, one of the best leads to come along in years, shows us a critical area of vulnerability on the virus that may be used to target with vaccines, sum up the researchers.


This neutralizing antibody binds to a HIV surface protein called gp120. Until now, no one had succeeded in determining the detailed structure of b12 in complex with gp120. It was extremely difficult to crystallize b12 bound to gp120, say the researchers in the 15 February online issue of Nature, in part due to the inherently flexible nature of the chemical bonds in gp120. To overcome the problem, the investigators created a variety of gp120s and eventually made the protein stiff enough to capture a picture of it in complex with b12. They saw that b12 binds gp120 at the same point where gp120 initially attaches to CD4 (a type of host’s cell surface protein).