Highly Selective Cyclic Peptide Ligands for NeutrAvidin and Avidin Identified by Phage Display

Screening combinatorial libraries of conformationally constrained peptides against macromolecular targets is utilized in identifying novel drug leads and in developing new reagents for chemical biology. In methods such as phage‐display selections, biotinylated macromolecular targets are often immobilized on avidin‐ and streptavidin‐functionalized supports. Thus, the characterization of peptides that bind avidin and streptavidin is necessary for accurate interpretation of screening and selection results. Toward this goal, we panned a phage‐displayed cyclic peptide library against NeutrAvidin, a chemically deglycosylated version of avidin. The selection produced a highly homologous consensus motif (Asp‐Arg/Leu‐Ala‐Ser/Thr‐Pro‐Tyr/Trp). Two of these cyclic peptides, CDRATPYC and CDRASPYC, bound both NeutrAvidin and avidin with low‐micromolar dissociation constants, whereas their acyclic counterparts had negligible affinity (