Structure-function analysis of a phage display-derived peptide that binds to insulin-like growth factor binding protein 1.
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.
Skelton
N J
NJ
Department of Protein Engineering, Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, USA. skelly@gene.com
Chen
Y M
YM
Dubree
N
N
Quan
C
C
Jackson
D Y
DY
Cochran
A
A
Zobel
K
K
Deshayes
K
K
Baca
M
M
Pisabarro
M T
MT
Lowman
H B
HB
D000409:Alanine / Q000235:genetics; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D017104:Bacteriophage M13 / Q000378:metabolism*; D001667:Binding, Competitive / Q000235:genetics; D016466:CHO Cells; D017124:Conserved Sequence; D006224:Cricetinae; D018360:Crystallography, X-Ray; D006801:Humans; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007700:Kinetics; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019151:Peptide Library; D010455:Peptides / Q000138:chemical synthesis / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D020349:Surface Plasmon Resonance; D013499:Surface Properties
D018970:Insulin-Like Growth Factor Binding Protein 1; D019151:Peptide Library; D010455:Peptides; D007334:Insulin-Like Growth Factor I; D000409:Alanine