Journal Article

The structural basis for dynamic DNA binding and bridging interactions which condense the bacterial centromere

Murray, Heath, Pastrana, César L, Higman, Victoria A, Butterer, Annika, Sobott, Frank, Fisher, Gemma LM, Dillingham, Mark S, Crump, Matthew P, Koh, Alan, Taylor, James A, Craggs, Timothy, Moreno-Herrero, Fernando

2017

Overview

The ParB protein forms DNA bridging interactions around parS to condense DNA and earmark the bacterial chromosome for segregation. The molecular mechanism underlying the formation of these ParB networks is unclear. We show here that while the central DNA binding domain is essential for anchoring at parS, this interaction is not required for DNA condensation. Structural analysis of the C-terminal domain reveals a dimer with a lysine-rich surface that binds DNA non-specifically and is essential for DNA condensation in vitro. Mutation of either the dimerisation or the DNA binding interface eliminates ParB-GFP foci formation in vivo. Moreover, the free C-terminal domain can rapidly decondense ParB networks independently of its ability to bind DNA. Our work reveals a dual role for the C-terminal domain of ParB as both a DNA binding and bridging interface, and highlights the dynamic nature of ParB networks in Bacillus subtilis.

• Publisher: eLife Science Publications, Ltd,eLife Sciences Publications Ltd,eLife Sciences Publications, Ltd
• Subject: Bacillus subtilis - genetics / bacterial centromere / Bacterial genetics / Biology / Centromere - metabolism / chromosome segregation / Chromosomes / Chromosomes and Gene Expression / Condensation / Deoxyribonucleic acid / DNA / DNA, Bacterial - metabolism / DNA-Binding Proteins - metabolism / Genetic research / Genetic testing / Lysine / Nature / NMR / ParB protein / Protein Binding / Protein Multimerization / Proteins / single-molecule / Spo0J / Standard deviation / Structural Biology and Molecular Biophysics