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

Abstract : 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.
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https://hal.archives-ouvertes.fr/hal-01191677
Contributeur : L2c Aigle <>
Soumis le : mercredi 2 septembre 2015 - 12:11:10
Dernière modification le : jeudi 6 juillet 2017 - 10:47:17

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Aurore Sanchez, Diego Cattoni, Jean-Charles Walter, Jérôme Rech, Andrea Parmeggiani, et al.. Stochastic Self-Assembly of ParB Proteins Builds the Bacterial DNA Segregation Apparatus. Cell Systems, 2015, 1, pp.163-173. <10.1016/j.cels.2015.07.013>. <hal-01191677>

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