- Stochastic Self-Assembly of ParB Proteins Builds the Bacterial DNA Segregation Apparatus doi link

Auteur(s): Sanchez Aurore, Cattoni Diego, Walter J.-C., Rech Jérôme, Parmeggiani A., Nollmann Marcelo, Bouet Jean-yves

(Article) Publié: Cell Systems, vol. 1 p.163-173 (2015)

Ref HAL: hal-01191677_v1
DOI: 10.1016/j.cels.2015.07.013
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14 citations

Many canonical processes in molecular biology rely on the dynamic assembly of higher-order nucleoprotein complexes. In bacteria, the assembly mechanism of ParABS, the nucleoprotein super-complex that actively segregates the bacterial chromosome and many plasmids, remains elusive. We combined super-resolution microscopy, quantitative genome-wide surveys, biochemistry, and mathematical modeling to investigate the assembly of ParB at the centromere-like sequences parS. We found that nearly all ParB molecules are actively confined around parS by a network of synergistic protein-protein and protein-DNA interactions. Interrogation of the empirically determined, high-resolution ParB genomic distribution with modeling suggests that instead of binding only to specific sequences and subsequently spreading, ParB binds stochastically around parS over long distances. We propose a new model for the formation of the ParABS partition complex based on nucleation and caging: ParB forms a dynamic lattice with the DNA around parS.This assembly model and approach to characterizing large-scale, dynamic interactions between macro-molecules may be generalizable to many unrelated machineries that self-assemble in superstructures.