Docking of peptide-T onto the D1 domain of the CD4 receptor.

Peptide T (pepT) is a segment of the human immunodeficiency virus (HIV) envelope protein gp120. The peptide competitively binds to the CD4 receptor of a subset of peripheral T lymphocytes and inhibits binding of gp120. Previous studies of this laboratory allowed the assessment of a bioactive form of the peptide and a pharmacophore for the peptide-receptor interaction. In the present study the proposed bioactive form of pepT and its (4-8) segment, the smallest pepT fragment shown to retain full activity, were docked onto the D1 domain of the CD4 receptor. The bioactive conformation of the peptides complements well a cleft on the surface of the CD4 receptor, shown to be the attachment site of gp120 from site directed mutagenesis experiments. These studies provide an improved description of the ligand-receptor pharmacophore.