title: Direct observation of DNA distortion by the RSC complex.
abstract: The Snf2 family represents a functionally diverse class of ATPase sharing the ability to modify DNA structure. Here, we use a magnetic trap and an atomic force microscope to monitor the activity of a member of this class: the RSC complex. This enzyme caused transient shortenings in DNA length involving translocation of typically 400 bp within 2 s, resulting in the formation of a loop whose size depended on both the force applied to the DNA and the ATP concentration. The majority of loops then decrease in size within a time similar to that with which they are formed, suggesting that the motor has the ability to reverse its direction. Loop formation was also associated with the generation of negative DNA supercoils. These observations support the idea that the ATPase motors of the Snf2 family of proteins act as DNA translocases specialized to generate transient distortions in DNA structure.
authors.affiliation: Laboratoire de Physique Statistique and Department Biologie, Ecole Normale Supérieure, CNRS-UMR 8550, 24 rue Lhomond, 75231 Paris Cedex 05, France.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lia
authors.forename: Elise
authors.initials: E
authors.lastname: Praly
authors.forename: Helder
authors.initials: H
authors.lastname: Ferreira
authors.forename: Chris
authors.initials: C
authors.lastname: Stockdale
authors.forename: Yuk Ching
authors.initials: YC
authors.lastname: Tse-Dinh
authors.forename: David
authors.initials: D
authors.lastname: Dunlap
authors.forename: Vincent
authors.initials: V
authors.lastname: Croquette
authors.forename: David
authors.initials: D
authors.lastname: Bensimon
authors.forename: Tom
authors.initials: T
authors.lastname: Owen-Hughes
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D026942:DNA Topoisomerases / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013314:Stress, Mechanical; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; C103337:RSC complex, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004247:DNA; D000251:Adenosine Triphosphatases; D026942:DNA Topoisomerases