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The evidence of large-scale DNA-induced compaction in the mycobacterial chromosomal ParB

Barnali N Chaudhuri1, Rebecca Dean

  • 1Hauptman Woodward Institute, Buffalo, NY 14203, USA. bchaudhuri@hwi.buffalo.edu

Journal of Molecular Biology
|August 16, 2011
PubMed

Insights

The bacterial segrosome

Area of Science:

  • Microbiology
  • Molecular Biology
  • Structural Biology

Background:

  • The segrosome is crucial for bacterial chromosome segregation before cell division.
  • ParB protein binds to parS DNA sites and polymerizes to form nucleoprotein filaments for segregation.

Purpose of the Study:

  • To investigate the structural characteristics of the apo (unbound) form of mycobacterial ParB.
  • To understand the conformational changes in ParB upon binding to parS DNA.

Main Methods:

  • Static light scattering (SLS)
  • Circular dichroism (CD) spectroscopy
  • Small-angle X-ray scattering (SAXS)

Main Results:

  • Apo mycobacterial ParB exists as an elongated dimer in solution, featuring intrinsically disordered regions and folded domains.
  • DNA binding induces significant compaction of the ParB protein structure.
  • This conformational change is proposed to facilitate ParB polymerization on the DNA template.

Conclusions:

  • Mycobacterial ParB undergoes a DNA-induced conformational transition.
  • This transition is critical for initiating ParB polymerization and subsequent chromosome segregation.
  • The study provides insights into the mechanism of bacterial chromosome segregation.

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