Researchers at the University of Michigan said they used computer models to develop a compound that inhibits the HIV protease -- an enzyme that promotes the replication of the virus. The scientists said their achievement might lead to a new class of AIDS drugs.

The study's principal investigator, Professor Heather Carlson, stressed the finding is only a preliminary, yet significant, step.

"It's very easy to make an inhibitor, (but) it's very hard to make a drug," said Carlson. "This compound is too weak to work in the human body. The key is to find more compounds that will work by the same mechanism."

The study appeared in the March 31 online edition of the journal Biopolymers.