Aug. 17 (HealthDay News) -- Researchers report they were able to block HIV infections in the lab with synthetic proteins that prevented the virus from entering healthy cells.

In the study, researchers developed synthetic molecules that interfered with the ability of a key HIV protein called gp41 to interact with proteins in host cells.

By interrupting the interaction, HIV could not infect the cells, according to the study that appears online Aug. 17 in the Proceedings of the National Academy of Sciences.

Interactions among proteins occur as part of biological processes, including infections and tumor growth, the researchers explained.

"There's a lot of information transfer that occurs when proteins come together, and one would often like to block that information flow," Samuel Gellman, a chemistry professor at the University of Wisconsin-Madison, said in a news release from the school.

Past attempts to prevent infection by selectively interfering with protein interactions have had limited success, he said. Most drugs are not effective at blocking protein-to-protein interactions.

Short snippets of proteins, or peptides, have been shown to be somewhat effective, but they are easily broken down by enzymes in the body, according to the news release.

The new synthetic peptide-like molecules overcome that because of a modified structure that enzymes have trouble recognizing.

In the study, the synthetic molecules interacted with gp41 to prevent the virus from infecting host cells. The synthetic molecules were altered to improve their ability to withstand enzyme degradation, yet retained the three-dimensional shape necessary to recognize HIV's gp41 protein.

"We want to find an alternate language, an alternate way to express the information that the proteins express so that we can interfere with a conversation that one protein is having with another," Gellman explained.

The idea shows promise in developing treatments for other disease-causing protein interactions as well, including influenza and Ebola virus, Gellman added.

The study was supported by grants from the U.S. National Institutes of Health.

SOURCE: University of Wisconsin-Madison, news release, Aug. 17, 2009