PREreviews of “A novel nuclease is the executing part of a bacterial plasmid defense system”

Skip to preprint details Skip to PREreviews

A novel nuclease is the executing part of a bacterial plasmid defense system

by Manuela Weiß, Giacomo Giacomelli, Mathilde Ben Assaya, Finja Grundt, Ahmed Haouz, Feng Peng, Stéphanie Petrella, Anne Marie Wehenkel, and Marc Bramkamp

Posted: October 6, 2022
Server: bioRxiv
DOI: 10.1101/2022.10.06.511153

Abstract

Cells are continuously facing the risk of taking up foreign DNA that can compromise genomic and cellular integrity. Therefore, bacteria are in a constant arms race with mobile genetic elements such as phages, transposons and plasmids. They have developed several active strategies against invading DNA molecules that can be seen as a bacterial ‘innate immune system’. Anti-phage systems are usually organized in ‘defense islands’ and can consist of restriction-modification (R-M) systems, CRISPR-Cas, and abortive infection (Abi) systems. Despite recent advances in the field, much less is known about plasmid defense systems. We have recently identified the MksBEFG system inCorynebacterium glutamicumas a novel plasmid defense system which comprises homologues of the condensin system MukFEB. Here, we investigated the molecular arrangement of the MksBEFG complex. Importantly, we identified MksG as a novel nuclease that degrades plasmid DNA and is, thus, the executing part of the system. The crystal structure of MksG revealed a dimeric assembly through its DUF2220 C-terminal domains. This domain is homologous to the TOPRIM domain of the topoisomerase II family of enzymes and contains the corresponding divalent ion binding site that is essential for DNA cleavage in topoisomerases, explaining thein vitronuclease activity of MksG. We further show that the MksBEF subunits exhibit an ATPase cycle similar to MukBEFin vitroand we reason that this reaction cycle, in combination with the nuclease activity provided by MksG, allows for processive degradation of invading plasmids. Super-resolution localization microscopy revealed that the Mks system is spatially regulated via to the polar scaffold protein DivIVA. Introduction of plasmids increases the diffusion rate and alters the localization of MksG, indicating an activation of the systemin vivo.

Read the preprint

1 PREreview

Write a PREreview Request a PREreview

PREreview by ambre jousselin et al.

Authored by ambre jousselin, Gauthier Chauvin, Cédric Coupet, Marie Dewailly, Chloé Garcia, Marius Lorendeau, Mathias Orlando, Marvin Ramos-Hue, Virgile Rose, Esther Pouzet, Marion Tassoni, Sylvain Vicente, and Peter Redder

Chauvin Gauthier, Coupet Cédric, Dewailly Marie, Garcia Chloé, Lorendeau Marius, Orlando Mathias, Ramos-Hue Marvin, Rose Virgile, Pouzet Esther, Rose Virgile, Tassoni Marion, Vicente Sylvain, Jousselin Ambre, Redder Peter
Université Toulouse Paul Sabatier, Master Microbiologie Moléculaire
LMGM-CBI,…

Read the PREreview by ambre jousselin et al.

PREreviews of A novel nuclease is the executing part of a bacterial plasmid defense system

1 PREreview