Related Experiment Video
Updated: Jun 10, 2026
08:33
Ubiquitin Chain Analysis by Parallel Reaction Monitoring
Published on: June 17, 2020
Mechanism for recognition of polyubiquitin chains: balancing affinity through interplay between multivalent binding
Craig J Markin1, Wei Xiao, Leo Spyracopoulos
1Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
Journal of the American Chemical Society
|August 12, 2010
Summary
RAP80
Area of Science:
- Biochemistry
- Molecular Biology
- Cellular Biology
Background:
- RAP80 is crucial for DNA damage response signaling.
- It recruits proteins to damage sites by binding K63-polyubiquitin chains via tandem ubiquitin-interacting motifs (tUIM).
- Understanding ubiquitin signal amplification mechanisms is complex.
Purpose of the Study:
- To elucidate the molecular mechanism of RAP80-tUIM interaction with polyubiquitin chains.
- To explain how RAP80 achieves enhanced affinity for signal amplification in DNA damage response.
Main Methods:
- Solution-state Nuclear Magnetic Resonance (NMR) spectroscopy.
- Molecular dynamics (MD) simulations.
- Biophysical interaction studies.
Main Results:
- RAP80-tUIM utilizes mono- and multivalent interactions with polyubiquitin chains for enhanced affinity.
- Increased affinity with polyubiquitin chain length is due to more binding sites.
- Weak interactions with fast off-rates characterize these binding events.
- Enhanced affinity is entropically balanced by restricted domain reorientation.
Conclusions:
- RAP80-tUIM binding mechanism explains ubiquitin signal amplification.
- Weak interactions and fast kinetics contribute to the transient nature of DNA damage foci.
- This study provides molecular insights into ubiquitin signaling in DNA repair.
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