Designing small-molecule switches for protein-protein interactions.
Mutations introduced into human growth hormone (hGH) (Thr175 --> Gly-hGH) and the extracellular domain of the hGH receptor (Trp104 --> Gly-hGHbp) created a cavity at the protein-protein interface that resulted in binding affinity being reduced by a factor of 10(6). A small library of indole analogs was screened for small molecules that bind the cavity created by the mutations and restore binding affinity. The ligand 5-chloro-2-trichloromethylimidazole was found to increase the affinity of the mutant hormone for its receptor more than 1000-fold. Cell proliferation and JAK2 phosphorylation assays showed that the mutant hGH activates growth hormone signaling in the presence of added ligand. This approach may allow other protein-protein and protein-nucleic acid interactions to be switched on or off by the addition or depletion of exogenous small molecules.
Guo
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Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Zhou
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D
Schultz
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PG
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002455:Cell Division; D002460:Cell Line; D019382:Human Growth Hormone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007093:Imidazoles / Q000737:chemistry* / Q000378:metabolism; D053614:Janus Kinase 2; D008024:Ligands; D051379:Mice; D008969:Molecular Sequence Data; D019151:Peptide Library; D010766:Phosphorylation; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D011986:Receptors, Somatotropin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D014162:Transfection
C409974:5-chloro-2-trichloromethylimidazole; D007093:Imidazoles; D008024:Ligands; D019151:Peptide Library; D011518:Proto-Oncogene Proteins; D011986:Receptors, Somatotropin; D019382:Human Growth Hormone; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2