Probing SWI/SNF remodeling of the nucleosome by unzipping single DNA molecules
Graduate School of Biomedical Sciences; PetersonCornell University; Department of Molecular Medicine
Life Sciences | Medicine and Health Sciences
Chromatin-remodeling enzymes can overcome strong histone-DNA interactions within the nucleosome to regulate access of DNA-binding factors to the genetic code. By unzipping individual DNA duplexes, each containing a uniquely positioned nucleosome flanked by long segments of DNA, we directly probed histone-DNA interactions. The resulting disruption-force signatures were characteristic of the types and locations of interactions and allowed measurement of the positions of nucleosomes with 2.6-base-pair (bp) precision. Nucleosomes remodeled by yeast SWI/SNF were moved bidirectionally along the DNA, resulting in a continuous position distribution. The characteristic distance of motion was approximately 28 bp per remodeling event, and each event occurred with a catalytic efficiency of 0.4 min(-1) per nM SWI/SNF. Remodeled nucleosomes had essentially identical disruption signatures to those of unremodeled nucleosomes, indicating that their overall structure remained canonical. These results impose substantial constraints on the mechanism of SWI/SNF remodeling.
DOI of Published Version
Nat Struct Mol Biol. 2006 Jun;13(6):549-54. Epub 2006 May 28. Link to article on publisher's site
Nature structural and molecular biology
Shundrovsky, Alla; Smith, Corey Lewis; Lis, John T.; Peterson, Craig L.; and Wang, Michelle D., "Probing SWI/SNF remodeling of the nucleosome by unzipping single DNA molecules" (2006). GSBS Student Publications. 1115.