Screening strategy for selecting capture agents against anti-HIV antibodies 3D6 and 4B3.

<p>The flow chart represents the use of the A21 and A22 cyclic peptides as anchor ligands for separate in situ click screens against a large OBOC azide-presenting peptide library.</p

Structures of peptide ligands in PCC Agent cocktail.

<p>Acetylene-presenting anchor peptides (black) were derived from the immunogenic epitope of HIV-1 gp41 (residues 600–612). A22-nindG (<b>i</b>) and A21-hnpfk (<b>ii</b>) were evolved from the original epitope appended with Pra at the C-terminus whereas A22-eihny (<b>iii</b>) utilizes the “substituted” anchor where residue Leu-607 is replaced with Pra. Secondary ligand branches (colored) were identified from the <i>in situ</i> click screen of a 5-mer OBOC library presenting an azide functionality. Biligands (<b>i</b>) and (<b>ii</b>) were raised against the target anti-HIV antibody 3D6, and the biligand (<b>iii</b>) was raised against the antibody 4B3.</p