Rapid identification of small binding motifs with high-throughput phage display: discovery of peptidic antagonists of IGF-1 function.
A panel of 22 naïve peptide libraries was constructed in a polyvalent phage display format and sorted against insulin-like growth factor-1 (IGF-1). The libraries were pooled to achieve a total diversity of 4.4 x 10(11). After three rounds of selection, the majority of the phage clones bound specifically to IGF-1, with a disulfide-constrained CX(9)C scaffold dominating the selection. Four monovalently displayed sub-libraries were designed on the basis of these conserved motifs. Sub-library maturation in a monovalent format yielded an antagonistic peptide that inhibited the interactions between IGF-1 and two cell-surface receptors and those between IGF-1 and two soluble IGF binding proteins with micromolar potency. NMR analysis revealed that the peptide is highly structured in the absence of IGF-1, and peptides that preorganize the binding elements were selected during the sorting.
Deshayes
Kurt
K
Department of Protein Engineering, Genentech, South San Francisco, CA 94080, USA. deshayes@gene.com
Schaffer
Michelle L
ML
Skelton
Nicholas J
NJ
Nakamura
Gerald R
GR
Kadkhodayan
Saloumeh
S
Sidhu
Sachdev S
SS
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D011956:Receptors, Cell Surface / Q000378:metabolism; D012995:Solubility; D014407:Tumor Cells, Cultured
D018969:Insulin-Like Growth Factor Binding Proteins; D019151:Peptide Library; D010455:Peptides; D011956:Receptors, Cell Surface; D007334:Insulin-Like Growth Factor I