Increased anti-HIV-1 activity of CD4 CDR3-related synthetic peptides by scrambling and further structural modifications, including D-isomerization and dimerization.

We recently showed that S1, a sequence-scrambled form of CD4 CDR3-related synthetic peptide, has more potent inhibitory activities on HIV-1 replication and HIV-1-induced syncytium formation than the original form. In this study, a series of derivatives of S1 were synthesized and their anti-HIV-1 activities were evaluated. A D-isomer was as potent as S1, and a homodimer was 10- to 18-fold more potent than S1. The increased antiviral activity of the dimer peptide was related to alpha-helix formation, as detected by circular dichroism.