HIV-2 Protease, an aspartyl protease (retropepsin), is essential for the life-cycle of HIV-2 sub-type virus. It is expressed in the infected cells as a part of Gag-Pol polyprotein from which it is auto-catalytically released after formation of an immature viral particle. The enzyme subsequently cleaves the other parts of viral polyproteins resulting in the maturation of the virus. In HIV-infected patients, the enzyme is subjected to intensive mutagenesis and mutants resistant to applied medicines are produced as a result of the selection pressure. The mutation of HIV protease's active site or inhibition of its activity disrupts HIV’s ability to replicate and infect additional cells. HIV-2 has been found to be less pathogenic than HIV-1. The mechanism of HIV-2 is not clearly defined, nor the difference from HIV-1, however the transmission rate is much lower in HIV-2 than HIV-1.
