ParA-mediated plasmid partition driven by protein pattern self-organization

EMBO J. 2013 May 2;32(9):1238-49. doi: 10.1038/emboj.2013.34. Epub 2013 Feb 26.


DNA segregation ensures the stable inheritance of genetic material prior to cell division. Many bacterial chromosomes and low-copy plasmids, such as the plasmids P1 and F, employ a three-component system to partition replicated genomes: a partition site on the DNA target, typically called parS, a partition site binding protein, typically called ParB, and a Walker-type ATPase, typically called ParA, which also binds non-specific DNA. In vivo, the ParA family of ATPases forms dynamic patterns over the nucleoid, but how ATP-driven patterning is involved in partition is unknown. We reconstituted and visualized ParA-mediated plasmid partition inside a DNA-carpeted flowcell, which acts as an artificial nucleoid. ParA and ParB transiently bridged plasmid to the DNA carpet. ParB-stimulated ATP hydrolysis by ParA resulted in ParA disassembly from the bridging complex and from the surrounding DNA carpet, which led to plasmid detachment. Our results support a diffusion-ratchet model, where ParB on the plasmid chases and redistributes the ParA gradient on the nucleoid, which in turn mobilizes the plasmid.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism*
  • Adenosine Triphosphate / metabolism*
  • Bacteriophage P1 / genetics*
  • Bacteriophage P1 / metabolism
  • Cell Division
  • DNA, Bacterial / genetics*
  • DNA, Bacterial / metabolism
  • F Factor / genetics*
  • F Factor / metabolism
  • Hydrolysis
  • Kinetics
  • Models, Biological*
  • Protein Binding
  • Protein Multimerization
  • Time-Lapse Imaging
  • Viral Proteins / metabolism*


  • DNA, Bacterial
  • ParB protein, Enterobacteria phage P1
  • Viral Proteins
  • Adenosine Triphosphate
  • Adenosine Triphosphatases