Action of RuvAB at replication fork structures

Peter McGlynn, R. G. Lloyd

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The replicative apparatus often encounters blocks to its progression that necessitate removal of the block and reloading of the replication machinery. In Escherichia coli, a major pathway of replication restart involves unwinding of the stalled fork to generate a four-stranded Holliday junction, which can then be cleaved by the RuvABC helicase-endonuclease. This fork regression may be catalyzed by RecG but is thought to occur even in its absence. Here we test whether RuvAB helicase can also catalyze the unwinding of forked DNA to form Holliday junctions. We find that fork DNA is unwound in the direction required for Holliday junction formation only if the loading of RuvB is restricted to the parental duplex DNA arm. If the binding of RuvB is unrestricted, then RuvAB preferentially unwinds forks in the opposite direction. This is probably related to the greater efficiency of two opposed RuvB hexamers operating across a junction compared with a single hexamer. These data argue against RuvAB acting directly at damaged replication forks and imply that other mechanisms must operate in vivo to catalyze Holliday junction formation.

Original languageEnglish
Pages (from-to)41938-41944
Number of pages6
JournalThe Journal of Biological Chemistry
Volume276
Issue number45
DOIs
Publication statusPublished - 2001

Keywords

  • HOLLIDAY JUNCTION COMPLEX
  • ESCHERICHIA-COLI
  • BRANCH MIGRATION
  • DNA-REPLICATION
  • IN-VITRO
  • HOMOLOGOUS RECOMBINATION
  • CRYSTAL-STRUCTURE
  • RECG
  • PROTEIN
  • PRIA

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