title: Highly selective cyclic peptide ligands for NeutrAvidin and avidin identified by phage display.
abstract: 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 (< 80-fold). Moreover, these cyclic peptides were very specific for their targets and did not bind the structurally and functionally similar protein, streptavidin. Thus, we have identified a new class of cyclic peptides, distinct from the much-studied streptavidin-binding His-Pro-Gln peptide motif. These results will not only allow for discriminating between desired and background cyclic peptide motifs in selections and screens but also provide a new protein/peptide model system and a useful reagent in chemical biology that can have utility in protein immobilization, purification, and chemical tagging.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Meyer
authors.forename: Thomas
authors.initials: T
authors.lastname: Gaj
authors.forename: Indraneel
authors.initials: I
authors.lastname: Ghosh
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001360:Avidin / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D001391:Azo Compounds / Q000378:metabolism; D017104:Bacteriophage M13 / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D015195:Drug Design; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019151:Peptide Library; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D019809:Streptavidin / Q000737:chemistry / Q000378:metabolism
chemical_list: D001391:Azo Compounds; C514999:CDRASPYC cyclic peptide; C514998:CDRATPYC cyclic peptide; D008024:Ligands; D019151:Peptide Library; D010456:Peptides, Cyclic; C093483:neutravidin; D001360:Avidin; C001413:HABA; D019809:Streptavidin