title: Topological characterization of the DnaA-oriC complex using single-molecule nanomanipuation.
abstract: In most bacteria, the timing and synchrony of initiation of chromosomal replication are determined by the binding of the AAA(+) protein DnaA to a set of high- and low-affinity sites found within the origin of chromosomal replication (oriC). Despite the large amount of information on the role and regulation of DnaA, the actual structure of the DnaA-oriC complex and the mechanism by which it primes the origin for the initiation of replication remain unclear. In this study, we have performed magnetic tweezers experiments to investigate the structural properties of the DnaA-oriC complex. We show that the DnaA-ATP-oriC complex adopts a right-handed helical conformation involving a variable amount of DNA and protein whose features fit qualitatively as well as quantitatively with an existing model based on the crystal structure of a truncated DnaA tetramer obtained in the absence of DNA. We also investigate the topological effect of oriC's DNA unwinding element.
authors.affiliation: Institut Jacques Monod, CN RS UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, F-75205 Paris, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Zorman
authors.forename: H
authors.initials: H
authors.lastname: Seitz
authors.forename: B
authors.initials: B
authors.lastname: Sclavi
authors.forename: T R
authors.initials: TR
authors.lastname: Strick
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001696:Biomechanical Phenomena; D004269:DNA, Bacterial / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D009154:Mutation; D051738:Origin Recognition Complex / Q000737:chemistry* / Q000235:genetics; D018741:Replication Origin
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; C114650:OriC chromosomal replication origin; D051738:Origin Recognition Complex; D000255:Adenosine Triphosphate