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Hydrodynamic bead modelling of the 2:1 p50-IkappaBgamma complex
Michaela Smolle1, Ronald T Hay, Olwyn Byron
1Biomolecular Sciences Building, School of Biology, University of St. Andrews, The North Haugh, St. Andrews KY16 9ST, Scotland, UK.
Biophysical Chemistry
|March 27, 2004
Summary
The NFkappaB transcription factor p50 forms a dimer in solution, while its inhibitor IkappaBgamma exists as a monomer. They form a complex, revealing insights into immune and inflammatory gene regulation.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Nuclear factor kappa B (NFkappaB) is a critical transcription factor regulating immune, inflammatory, and survival responses.
- Gene regulation specificity involves distinct DNA binding preferences of NFkappaB dimers and complex inhibitor degradation pathways.
Purpose of the Study:
- To model the solution structures of the NFkappaB family member p50, its inhibitor IkappaBgamma, and their complex.
- To understand the conformational states of p50 and IkappaBgamma in solution and their interaction.
Main Methods:
- Analytical ultracentrifugation (AUC)
- Sedimentation equilibrium (SE)
- Sedimentation velocity (SV)
- Hydrodynamic bead modeling
Main Results:
- p50 exists as a dimer in solution, adopting a conformation intermediate between closed and open states.
- IkappaBgamma is a monomer in solution and shows a tendency to aggregate.
- A 2:1 stoichiometric complex of p50 dimer and IkappaBgamma monomer is formed, suggesting a closed conformation for the p50 dimer.
Conclusions:
- The study elucidates the solution structures and interactions of p50 and IkappaBgamma.
- Findings provide insights into the conformational dynamics of NFkappaB dimers and their inhibitors.
- This structural understanding contributes to deciphering the mechanisms of NFkappaB-mediated gene regulation.