8B7F

Nuclease from C. glutamicum

Summary for 8B7F

• Entry DOI: 10.2210/pdb8b7f/pdb
• Descriptor: Ubiquitin-like protein SMT3,MksG (1 entity in total)
• Functional Keywords: nuclease, metal binding protein
• Biological source: Corynebacterium glutamicum ATCC 13032; More
• Total number of polymer chains: 2
• Total formula weight: 107306.86

Authors

Wehenkel, A.,Ben Assaya, M.,Haouz, A. (deposition date: 2022-09-29, release date: 2023-03-29, Last modification date: 2024-05-01)

Primary citation

Weiss, M.,Giacomelli, G.,Assaya, M.B.,Grundt, F.,Haouz, A.,Peng, F.,Petrella, S.,Wehenkel, A.M.,Bramkamp, M.
The MksG nuclease is the executing part of the bacterial plasmid defense system MksBEFG.
Nucleic Acids Res., 51:3288-3306, 2023

PubMed Abstract: Cells are continuously facing the risk of taking up foreign DNA that can compromise genomic 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'. Here, we investigated the molecular arrangement of the Corynebacterium glutamicum MksBEFG complex, which is homologous to the MukBEF condensin system. We show here that MksG is a nuclease that degrades plasmid DNA. The crystal structure of MksG revealed a dimeric assembly through its C-terminal domain that is homologous to the TOPRIM domain of the topoisomerase II family of enzymes and contains the corresponding ion binding site essential for DNA cleavage in topoisomerases. The MksBEF subunits exhibit an ATPase cycle in vitro and 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 the polar scaffold protein DivIVA. Introduction of plasmids results in an increase in DNA bound MksG, indicating an activation of the system in vivo.

PubMed: 36881760
DOI: 10.1093/nar/gkad130

Experimental method

X-RAY DIFFRACTION (4.6 Å)