HIV-1: fifteen proteins and an RNA.

Human immunodeficiency virus type 1 is a complex retrovirus encoding 15 distinct proteins. Substantial progress has been made toward understanding the function of each protein, and three-dimensional structures of many components, including portions of the RNA genome, have been determined. This review describes the function of each component in the context of the viral life cycle: the Gag and Env structural proteins MA (matrix), CA (capsid), NC (nucleocapsid), p6, SU (surface), and TM (transmembrane); the Pol enzymes PR (protease), RT (reverse transcriptase), and IN (integrase); the gene regulatory proteins Tat and Rev; and the accessory proteins Nef, Vif, Vpr, and Vpu. The review highlights recent biochemical and structural studies that help clarify the mechanisms of viral assembly, infection, and replication.