Researchers determine structure of key HIV protein

Researchers determined the structure of an important part of the HIV envelope protein that previously eluded detailed description, according to a study published on Monday in Proceedings of the National Academy of Sciences.

The Duke University research team determined the structure of the gp41 membrane proximal external region, which could help to focus HIV vaccine development efforts. The HIV's envelope protein complex is a structure that protrudes from HIV's membrane and infects healthy host cells. The complex contains three copies of the gp41 protein, in addition to a closely related partner protein, gp120.

The researchers said they think about a certain region of gp41, known as MPER, as the vulnerable Achilles' heel of the virus.

"The attractiveness of this region is that, number one, it is relatively conserved," Leonard Spicer, a senior author of the study, said. "Second, this region has two particular sequences of amino acids that code for the binding of important broadly neutralizing antibodies."

The Duke team used protein engineering, sophisticated nuclear magnetic resonance spectroscopy and specialized software to examine the dynamic intermediate step HIV uses to fuse to a host cell. While the pre- and post-fusion steps are stable and well studied, the intermediate step previously made it difficult to visualize with traditional structure determination techniques.

Using the new combination of techniques, the researchers were able to capture the shape of the three-parted MPER.

Researchers may be able to use the findings to target a virus that infected more than 33 million people and killed 30 million more.