Structure-function analysis of a phage display-derived peptide that binds to insulin-like growth factor binding protein 1.Skelton, N.J., Chen, Y.M., Dubree, N., Quan, C., Jackson, D.Y., Cochran, A., Zobel, K., Deshayes, K., Baca, M., Pisabarro, M.T., Lowman, H.B.
(2001) Biochemistry 40: 8487-8498
- PubMed: 11456486
- Primary Citation of Related Structures:  1GJE, 1GJF, 1IMW, 1IN2, 1IN3
- PubMed Abstract:
- Molecular Mimics of Insulin-like Growth Factor 1 (IGF-1) for Inhibiting IGF-1: IGF-Binding Protein Interactions
Lowman, H.B.,Chen, Y.M.,Skelton, N.J.,Mortensen, D.L.,Tomlinson, E.E.,Sadick, M.D.,Robinson, I.C.,Clark, R.G.
(1998) Biochemistry 37: 8870
Highly structured, peptide antagonists of the interaction between insulin-like growth factor 1 (IGF-I) and IGF binding protein 1 (IGFBP-1) have recently been discovered by phage display of naïve peptide libraries [Lowman, H. B., et al. (1998) Biochem ...
Highly structured, peptide antagonists of the interaction between insulin-like growth factor 1 (IGF-I) and IGF binding protein 1 (IGFBP-1) have recently been discovered by phage display of naïve peptide libraries [Lowman, H. B., et al. (1998) Biochemistry 37, 8870--8878]. We now report a detailed analysis of the features of this turn-helix peptide motif that are necessary for IGFBP-1 binding and structural integrity. Further rounds of phage randomization indicate the importance of residues contributing to a hydrophobic patch on one face of the helix. Alanine-scanning substitutions confirm that the hydrophobic residues are necessary for binding. However, structural analysis by NMR spectroscopy indicates that some of these analogues are less well folded. Structured, high-affinity analogues that lack the disulfide bond were prepared by introducing a covalent constraint between side chains at positions i and i + 7 or i + 8 within the helix. Analogues based on this scaffold demonstrate that a helical conformation is present in the bound state, and that hydrophobic side chains in this helix, and residues immediately preceding it, interact with IGFBP-1. By comparison of alanine scanning data for IGF-I and the turn-helix peptide, we propose a model for common surface features of these molecules that recognize IGFBP-1.
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