Abstract
We describe a general method for the mimicry of one face of an alpha-helix based on a terphenyl scaffold that spatially projects functionality in a manner similar to that of two turns of an alpha-helix. The synthetic scaffold reduces the flexibility and molecular weight of the mimicked protein secondary structure. We have applied this design to the development of antagonists of the alpha-helix binding protein Bcl-x(L). Using a sequential synthetic strategy, we have prepared a library of terphenyl derivatives to mimic the helical region of the Bak BH3 domain that binds Bcl-x(L). Fluorescence polarization assays were carried out to evaluate the ability of terphenyl derivatives to displace the Bcl-x(L)-bound Bak peptide. Terphenyl 14 exhibited good in vitro affinity with a K(i) value of 0.114 muM. These terphenyl derivatives were more selective at disrupting the Bcl-x(L)/Bak over the HDM2/p53 interaction, which involves binding of the N-terminal alpha-helix of p53 to HDM2. Structural studies using NMR spectroscopy and computer-aided docking simulations suggested that the helix binding area on the surface of Bcl-x(L) is the target for the synthetic ligands. Treatment of human embryonic kidney 293 (HEK293) cells with terphenyl derivatives resulted in the disruption of the binding of Bcl-x(L) to Bax in intact cells.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Biomimetic Materials / chemical synthesis
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Biomimetic Materials / chemistry
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Biomimetic Materials / pharmacology
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Cell Line
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Crystallography, X-Ray
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Fluorescence Polarization
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Humans
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Kinetics
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Membrane Proteins / antagonists & inhibitors
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Membrane Proteins / chemistry*
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Membrane Proteins / metabolism
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Membrane Proteins / pharmacology
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Models, Molecular
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Molecular Weight
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Peptide Fragments / chemistry
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Peptide Fragments / metabolism
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Peptide Fragments / pharmacology
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Protein Structure, Secondary
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Proto-Oncogene Proteins / chemistry
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins / pharmacology
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Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors*
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Proto-Oncogene Proteins c-bcl-2 / chemistry*
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Proto-Oncogene Proteins c-bcl-2 / pharmacology
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Structure-Activity Relationship
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Terphenyl Compounds / chemical synthesis
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Terphenyl Compounds / chemistry*
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Terphenyl Compounds / pharmacology*
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bcl-2 Homologous Antagonist-Killer Protein
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bcl-X Protein
Substances
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BAK1 protein, human
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BCL2L1 protein, human
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Bax protein (53-86)
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Membrane Proteins
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Peptide Fragments
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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Terphenyl Compounds
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bcl-2 Homologous Antagonist-Killer Protein
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bcl-X Protein