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Updated: Jul 11, 2026

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Published on: June 15, 2018
A small domain of CBP/p300 binds diverse proteins: solution structure and functional studies
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
The IRF-3 binding domain (IBiD) in CBP and p300 coactivators undergoes induced folding upon partner binding. This domain is crucial for integrating signals by CBP and p300, impacting gene expression regulation.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- CBP and p300 are essential transcriptional coactivators regulating gene expression in metazoans.
- These coactivators interact with various transcription factors via conserved domains.
Purpose of the Study:
- To identify and characterize the structure of a novel domain in CBP and p300 involved in protein interactions.
- To elucidate the mechanism of interaction between this domain and its diverse binding partners.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy to determine the 3D structure of the IRF-3 binding domain (IBiD).
- Spectroscopic techniques to analyze protein-protein interactions and conformational changes.
- In vitro and in vivo assays to assess the functional significance of IBiD interactions.
Main Results:
- A compactly folded 46-residue domain, termed IBiD, was identified in CBP and p300.
- The IBiD structure reveals a helical framework with a flexible polyglutamine loop involved in ligand binding.
- Induced folding of IBiD upon association with diverse partners, lacking sequence similarity, was observed.
- The functional significance of IBiD interactions was confirmed through in vitro and in vivo experiments.
Conclusions:
- IBiD is a key domain in CBP and p300, mediating interactions with multiple partners.
- Induced folding of IBiD is critical for its function in signal integration.
- This domain plays a significant role in the regulatory mechanisms of CBP and p300 in gene expression.
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