Solution Structure of the Human CD4 (403-419) Receptor Peptide.

The cytoplasmic part of CD4 is known to be essential for the interaction with the human immunodeficiency virus type 1 proteins Vpu and Nef. The 17 amino acid synthetic peptide CD4 (403-419) with the amino acid sequence of the membrane proximal part of the cytoplasmic domain of the human CD4 receptor was structurally investigated by circular dichroism and nuclear magnetic resonance spectroscopy. The average alpha-helical content of the peptide could be estimated to be around 25%. Chemical shift index analysis and the connectivity pattern in nuclear Overhauser enhancement spectra located the alpha-helical part of the peptide from Gln403 to Arg412. It may be speculated that this amphipathic alpha-helix is the contact region with the Vpu and Nef proteins. Copyright 1996 S. Karger AG, Basel