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The CSB protein actively wraps DNA
Nancy Beerens1, Jan H J Hoeijmakers, Roland Kanaar
1Department of Cell Biology and Genetics and Radiation Oncology, Erasmus Medical Center, P. O. Box 1738, 3000 DR Rotterdam, The Netherlands.
The Journal of Biological Chemistry
|November 19, 2004
Summary
The CSB protein wraps DNA in an ATP-dependent manner, suggesting a mechanism for altering DNA structure during transcription-coupled repair. This DNA wrapping and unwrapping influences protein-DNA interactions.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- CSB protein is an ATP-dependent chromatin remodeler.
- CSB is crucial for transcription-coupled DNA repair.
- CSB's precise role in DNA repair is not fully understood.
Purpose of the Study:
- To elucidate the structural changes in DNA induced by CSB binding.
- To understand the mechanism of CSB in DNA repair.
Main Methods:
- Scanning force microscopy (SFM) was used to analyze the CSB.DNA complex.
- DNA contour length was measured upon CSB binding with ATP and non-hydrolyzable ATP analogs.
Main Results:
- CSB binding in the presence of ATP reduced DNA contour length, indicating DNA wrapping.
- DNA wrapping was more frequent with non-hydrolyzable ATP analogs, suggesting ATP binding drives wrapping and hydrolysis drives unwrapping.
- Evidence suggests CSB binds DNA as a dimer.
Conclusions:
- CSB utilizes ATP binding and hydrolysis to dynamically wrap and unwrap DNA.
- This DNA conformational alteration is a key mechanism for CSB's function in DNA repair and chromatin remodeling.