title: The Localization and Action of Topoisomerase IV in Escherichia coli Chromosome Segregation Is Coordinated by the SMC Complex, MukBEF.
abstract: The type II topoisomerase TopoIV, which has an essential role in Escherichia coli chromosome decatenation, interacts with MukBEF, an SMC (structural maintenance of chromosomes) complex that acts in chromosome segregation. We have characterized the intracellular dynamics of individual TopoIV molecules and the consequences of their interaction with MukBEF clusters by using photoactivated-localization microscopy. We show that ~15 TopoIV molecules per cell are associated with MukBEF clusters that are preferentially localized to the replication origin region (ori), close to the long axis of the cell. A replication-dependent increase in the fraction of immobile molecules, together with a proposed catalytic cycle of ~1.8 s, is consistent with the majority of active TopoIV molecules catalyzing decatenation, with a minority maintaining steady-state DNA supercoiling. Finally, we show that the MukB-ParC interaction is crucial for timely decatenation and segregation of newly replicated ori DNA.
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
authors.forename: Pawel
authors.initials: P
authors.lastname: Zawadzki
authors.affiliation: Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Mathew
authors.initials: M
authors.lastname: Stracy
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Ginda
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Zawadzka
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Bases Moléculaires et Structurales des Systèmes Infectieux, UMR 5086, Centre National de la Recherche Scientifique, University of Lyon, 69367 Lyon, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Lesterlin
authors.affiliation: Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Achillefs N
authors.initials: AN
authors.lastname: Kapanidis
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. Electronic address: david.sherratt@bioch.ox.ac.uk.
authors.forename: David J
authors.initials: DJ
authors.lastname: Sherratt
mesh_terms: D055162:Biocatalysis; D043863:Catenanes / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation; D002876:Chromosomes, Bacterial / Q000378:metabolism; D027101:DNA Topoisomerase IV / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D005810:Multigene Family; D018741:Replication Origin; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D059008:Time-Lapse Imaging
chemical_list: D043863:Catenanes; D002868:Chromosomal Proteins, Non-Histone; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; D012097:Repressor Proteins; C087115:mukE protein, E coli; C087116:mukF protein, E coli; D027101:DNA Topoisomerase IV