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Overview of PIs
Mode of Action

Target enzyme: Protease

Press to see how Indinavir binds to the protease. Indinavir is in red, and the active site residues are in purple.

To see more visit: http://www.urmc.rochester.edu/smd/mbi/chime/prframe.html

Mode of Action

The HIV protease works by cutting up long chains of the virus' proteins and enzymes (polyproteins) into smaller pieces that go on to infect new cells. Potease inhibitors bind to the HIV protease and, whilst bound, prevent the enzyme from cutting the viral protein molecules to their correct sizes.This means the virus cannot make copies that can infect new cells. This all occurs near the end of the life cycle of the virus.

Most of these drugs are peptide-mimicking compounds. In other words, these compounds resemble the natural
substrate of the HIV protease. The inhibitors bind to the enzyme much more tightly than the natural substrate.

The protease inhibitors can slow virus production in both newly infected cells and cells that have been infected for a long time, this is different to the NRTIs and NNRTIs which only work on cells that have been infected for a short time.