Stepwise nucleosome translocation by RSC remodeling complexes
Bryan T Harada,
William L Hwang,
Sebastian Deindl,
Nilanjana Chatterjee,
Blaine Bartholomew,
Xiaowei Zhuang
Affiliations
Bryan T Harada
Graduate Program in Biophysics, Harvard University, Cambridge, United States; Howard Hughes Medical Institute, Harvard University, Cambridge, United States
William L Hwang
Graduate Program in Biophysics, Harvard University, Cambridge, United States; Howard Hughes Medical Institute, Harvard University, Cambridge, United States; Harvard/MIT MD-PhD Program, Harvard Medical School, Boston, United States
Sebastian Deindl
Howard Hughes Medical Institute, Harvard University, Cambridge, United States; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, United States
Nilanjana Chatterjee
Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, United States
Blaine Bartholomew
Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, United States
Xiaowei Zhuang
Howard Hughes Medical Institute, Harvard University, Cambridge, United States; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, United States; Department of Physics, Harvard University, Cambridge, United States
The SWI/SNF-family remodelers regulate chromatin structure by coupling the free energy from ATP hydrolysis to the repositioning and restructuring of nucleosomes, but how the ATPase activity of these enzymes drives the motion of DNA across the nucleosome remains unclear. Here, we used single-molecule FRET to monitor the remodeling of mononucleosomes by the yeast SWI/SNF remodeler, RSC. We observed that RSC primarily translocates DNA around the nucleosome without substantial displacement of the H2A-H2B dimer. At the sites where DNA enters and exits the nucleosome, the DNA moves largely along or near its canonical wrapping path. The translocation of DNA occurs in a stepwise manner, and at both sites where DNA enters and exits the nucleosome, the step size distributions exhibit a peak at approximately 1–2 bp. These results suggest that the movement of DNA across the nucleosome is likely coupled directly to DNA translocation by the ATPase at its binding site inside the nucleosome.
