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Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
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Conformations of p53 response elements in solution deduced using site-directed spin labeling and Monte Carlo sampling
Xiaojun Zhang1, Ana Carolina Dantas Machado, Yuan Ding
1Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA and Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
Nucleic Acids Research
|December 3, 2013
Summary
The tumor suppressor protein p53 recognizes DNA response elements (REs) through sequence-dependent shape features. This study reveals REs
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- The tumor suppressor protein p53 plays a crucial role in regulating cellular signaling pathways.
- p53 specifically recognizes and binds to diverse p53 response elements (REs) to exert its regulatory functions.
- Structural information on p53 REs in their unbound state is limited, hindering a full understanding of p53-DNA interactions.
Purpose of the Study:
- To investigate the solution structures of p53 REs involved in the regulation of p21 and Bax genes.
- To elucidate the mechanisms underlying p53-DNA recognition and binding specificity.
- To establish a novel experimental/computational approach for studying DNA shape in solution.
Main Methods:
- Site-directed spin labeling was employed to probe the solution structures of p21-RE and BAX-RE.
- Double-electron-electron-resonance (DEER) spectroscopy was used to measure distances within the REs.
- Monte Carlo simulations generated pools of all-atom structures, enabling the derivation of molecular models for unbound REs.
Main Results:
- Distinct conformational changes in REs were observed upon binding to the p53 core domain.
- Sequence-dependent DNA shape features of unbound REs in solution were revealed.
- The findings support the hypothesis that p53 exploits sequence-dependent RE properties for energetically favorable binding and enhanced specificity.
Conclusions:
- This study provides insights into the mechanisms of p53-DNA recognition.
- A new experimental/computational framework for studying DNA shape in solution was established.
- The developed approach has significant implications for the broader study of protein-DNA interactions.
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