Sommaire:

Most bacteria contain a single circular chromosome a thousand-fold longer than the bacteria itself. This chromosome is highly condensed and is organized in part by a large amount of associated proteins. Single-molecule experiments revealed that these proteins impact DNA structure by inducing bridging, bending, twisting, looping, or coiling. However, it remains unclear how such DNA-binding proteins collectively organize the bacterial chromosome. I will focus on what is arguably the most demanding organizational task for the bacterial chromosome: DNA replication and segregation, which is mediated by the ParABS system in many bacteria. At its heart, this segregation machinery includes a large protein-DNA complex consisting of roughly 1000 ParB proteins. However, the physical organization of ParB proteins on the DNA remains unclear. What controls the formation, localization, and stability of the ParB complex? We developed a simple model for interacting proteins on DNA. This model shows that a combination of 1D spreading bonds and a 3D bridging bond between ParB proteins constitutes a minimal model for condensation of ParB proteins into a 3D ParB-DNA complex.

Pour plus d'informations, merci de contacter Walter J.-C.