title: The RSC chromatin remodelling ATPase translocates DNA with high force and small step size.
abstract: ATP-dependent chromatin remodelling complexes use the energy of ATP hydrolysis to reposition and reconfigure nucleosomes. Despite their diverse functions, all remodellers share highly conserved ATPase domains, many shown to translocate DNA. Understanding remodelling requires biophysical knowledge of the DNA translocation process: how the ATPase moves DNA and generates force, and how translocation and force generation are coupled on nucleosomes. Here, we characterize the real-time activity of a minimal RSC translocase 'motor' on bare DNA, using high-resolution optical tweezers and a 'tethered' translocase system. We observe on dsDNA a processivity of ∼35 bp, a speed of ∼25 bp/s, and a step size of 2.0 (±0.4, s.e.m.) bp. Surprisingly, the motor is capable of moving against high force, up to 30 pN, making it one of the most force-resistant motors known. We also provide evidence for DNA 'buckling' at initiation. These observations reveal the ATPase as a powerful DNA translocating motor capable of disrupting DNA-histone interactions by mechanical force.
authors.affiliation: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, USA.
authors.forename: George
authors.initials: G
authors.lastname: Sirinakis
authors.forename: Cedric R
authors.initials: CR
authors.lastname: Clapier
authors.forename: Ying
authors.initials: Y
authors.lastname: Gao
authors.forename: Ramya
authors.initials: R
authors.lastname: Viswanathan
authors.forename: Bradley R
authors.initials: BR
authors.lastname: Cairns
authors.forename: Yongli
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000493:pharmacokinetics*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry* / Q000493:pharmacokinetics*; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000235:genetics / Q000493:pharmacokinetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000493:pharmacokinetics; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000235:genetics / Q000493:pharmacokinetics*; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010865:Pilot Projects; D011499:Protein Processing, Post-Translational; D021381:Protein Transport / Q000235:genetics; D013997:Time Factors
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D020409:Molecular Motor Proteins; D009707:Nucleosomes; D012321:DNA-Directed RNA Polymerases; D000251:Adenosine Triphosphatases