Recycling of single-stranded DNA-binding protein by the bacterial replisome

Lisanne M. Spenkelink, Jacob S. Lewis, Slobodan Jergic, Zhi-Qiang Xu, Andrew Robinson, Nicholas E. Dixon*, Antoine M. van Oijen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

9 Citations (Scopus)
86 Downloads (Pure)

Abstract

Single-stranded DNA-binding proteins (SSBs) support DNA replication by protecting single-stranded DNA from nucleolytic attack, preventing intra-strand pairing events and playing many other regulatory roles within the replisome. Recent developments in single-molecule approaches have led to a revised picture of the replisome that is much more complex in how it retains or recycles protein components. Here, we visualize how an in vitro reconstituted Escherichia coli replisome recruits SSB by relying on two different molecular mechanisms. Not only does it recruit new SSB molecules from solution to coat newly formed single-stranded DNA on the lagging strand, but it also internally recycles SSB from one Okazaki fragment to the next. We show that this internal transfer mechanism is balanced against recruitment from solution in a manner that is concentration dependent. By visualizing SSB dynamics in live cells, we show that both internal transfer and external exchange mechanisms are physiologically relevant.

Original languageEnglish
Pages (from-to)4111-4123
Number of pages13
JournalNucleic Acids Research
Volume47
Issue number8
DOIs
Publication statusPublished - 7-May-2019

Keywords

  • FACILITATED DISSOCIATION
  • EQUILIBRIUM BINDING
  • MODE TRANSITIONS
  • REPLICATION FORK
  • NUCLEIC-ACIDS
  • MOLECULE
  • SSB
  • MECHANISM
  • COMPLEXES
  • DYNAMICS

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