title: New binding specificities derived from Min-23, a small cystine-stabilized peptidic scaffold.
abstract: The randomization of both internal and surface residues in small protein domains followed by selection from a display library is emerging as a powerful strategy to obtain novel binding specificities. Small and stable scaffold motifs observed in disulfide-rich proteins are attractive because they are small, stable, and accessible to chemical synthesis. The elementary structural motif found in the squash trypsin inhibitor EETI-II (Ecballium elaterium trypsin inhibitor) is the cystine stabilized beta-sheet (CSB) motif, found in nearly 50% of all known small disulfide-rich protein families. We have used Min-23, a short 23-residue peptide containing the CSB motif and shown to be a stable autonomous folding unit and one of the smallest scaffolds described to date, as a scaffold for selection of new binding ligands. We demonstrate that the core CSB motif in Min-23 is permissive to loop insertion, using peptide epitopes from hemagglutinin (HA) and Gla-protein (E). A phage library of more than 10(8) different clones has been constructed by insertion of a randomized sequence on a beta-turn of the Min-23 peptide. The selection of this library on a variety of 7 different targets allowed the isolation of 21 new specific binders, confirming the potential of Min-23 as a scaffold for the development of new ligands. The derived library is able to provide a wide range of novel compounds with possible applications in various biological and pharmaceutical areas.
authors.affiliation: CRC for Diagnostics at CSIRO Health Sciences and Nutrition, 343 Royal Parade, Parkville, Victoria, 3052 Australia.
authors.forename: Christelle
authors.initials: C
authors.lastname: Souriau
authors.forename: Laurent
authors.initials: L
authors.lastname: Chiche
authors.forename: Robert
authors.initials: R
authors.lastname: Irving
authors.forename: Peter
authors.initials: P
authors.lastname: Hudson
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D003001:Cloning, Molecular; D003090:Coliphages / Q000235:genetics; D019662:Cucurbitaceae; D003553:Cystine / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000235:genetics; D005822:Genetic Vectors; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D019151:Peptide Library; D033902:Periplasmic Binding Proteins / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D020349:Surface Plasmon Resonance
chemical_list: D000953:Antigens, Protozoan; D004220:Disulfides; D029968:Escherichia coli Proteins; D019267:Hemagglutinin Glycoproteins, Influenza Virus; C461619:MalE protein, E coli; D008565:Membrane Proteins; D010446:Peptide Fragments; D019151:Peptide Library; D033902:Periplasmic Binding Proteins; D010940:Plant Proteins; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C090077:apical membrane antigen I, Plasmodium; C063950:trypsin inhibitor EETI II protein, plant; D003553:Cystine