ATP control of dynamic P1 ParA-DNA interactions: a key role for the nucleoid in plasmid partition

Mol Microbiol. 2010 Oct;78(1):78-91. doi: 10.1111/j.1365-2958.2010.07314.x. Epub 2010 Jul 27.


P1 ParA is a member of the Walker-type family of partition ATPases involved in the segregation of plasmids and bacterial chromosomes. ATPases of this class interact with DNA non-specifically in vitro and colocalize with the bacterial nucleoid to generate a variety of reported patterns in vivo. Here, we directly visualize ParA binding to DNA using total internal reflection fluorescence microscopy. This activity depends on, and is highly specific for ATP. DNA-binding activity is not coupled to ATP hydrolysis. Rather, ParA undergoes a slow multi-step conformational transition upon ATP binding, which licenses ParA to bind non-specific DNA. The kinetics provide a time-delay switch to allow slow cycling between the DNA binding and non-binding forms of ParA. We propose that this time delay, combined with stimulation of ParA's ATPase activity by ParB bound to the plasmid DNA, generates an uneven distribution of the nucleoid-associated ParA, and provides the motive force for plasmid segregation prior to cell division.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism*
  • Adenosine Triphosphate / metabolism*
  • DNA, Bacterial / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Escherichia coli / enzymology
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Plasmids / metabolism*


  • DNA, Bacterial
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • ParA protein, E coli
  • Adenosine Triphosphate
  • Adenosine Triphosphatases