Therapeutic approaches to human immunodeficiency virus: Structural studies on G-protein-coupled receptors

Infection by human immunodeficiency virus (HIV) requires the presence of a chemokine receptor on the susceptible cell. The expression of two different chemokine receptors on macrophages and lymphocytes explains the selectivity of different HIV isolates. The rationale behind the choice of the chemokine receptor (CCR5) expressed on macrophages as a therapeutic target is based on the epidemiological studies of the impact on HIV infectivity of a human mutation that prevents expression of this receptor. CCR5 is a member of the G-protein-coupled receptor family, which has yet to be characterized structurally at atomic resolution. Efforts to model the three-dimensional structure of such receptors and to characterize them experimentally are underway in many laboratories. As an example, structural studies determining the bound conformation of the C-terminal peptide of the α-subunit of transducin, the relevant G-protein of vision, with rhodopsin are presented.