MU researchers decode critical HIV protein

MU scientists have gotten one step closer to unraveling HIV: a team of researchers captured a detailed image of a major protein in the virus, the capsid protein, which may help explain some of the virus’ complexities. The protein was captured by a team led by Dr. Stefan Sarafianos, associate professor of molecular microbiology and immunology and the chancellor’s chair of excellence in molecular virology in the MU School of Medicine.

“The capsid shell acts as an ‘invisibility cloak’ that hides the virus’ genetic information, the genome, while it is being copied in a hostile environment for the virus,” Sarafianos said in a press release. “Fine-tuned capsid stability is critical for successful infection: too stable a capsid shell, and the cargo is never delivered properly; not stable enough, and the contents are detected by our immune defenses, triggering an antiviral response. Capsid stability is a key to the puzzle, and you have to understand its structure to solve it.”

This research was funded by the National Institutes of Health, which gave the team an additional $2.28 million to continue research over the next five years. Sarafianos and his team hope to take their findings and develop new antiviral drugs to combat HIV.

With the photo captured, Sarafiano’s team constructed a model of the protein using X-ray crystallography. They were able to make a 3-D map of the capsid protein by shooting X-rays at the crystal structure they had made and seeing where the rays ricocheted.

The model they created showed water to be a vital part of the protein’s construction.

“We thought, ‘How could some simple water molecules really be of consequence?’” Sarafianos said. “But when we looked carefully, we realized there are thousands of waters that help stabilize the complex capsid scaffold. We hypothesized that this is an essential part of the stability of the whole capsid assembly.”

Images provided by MU News Bureau.