4MN4

Structural Basis for the MukB-topoisomerase IV Interaction

Summary for 4MN4

• Entry DOI: 10.2210/pdb4mn4/pdb
• Descriptor: DNA topoisomerase 4 subunit A, Chromosome partition protein MukB (3 entities in total)
• Functional Keywords: beta-pinwheel, chromosome partitioning, isomerase-cell cycle complex, isomerase/cell cycle
• Biological source: Escherichia coli; More
• Cellular location: Cell membrane; Peripheral membrane protein: P0AFI2; Cytoplasm, nucleoid: P22523
• Total number of polymer chains: 4
• Total formula weight: 93286.21

Authors

Vos, S.M.,Stewart, N.K.,Oakley, M.G.,Berger, J.M. (deposition date: 2013-09-09, release date: 2013-10-23, Last modification date: 2024-11-06)

Primary citation

Vos, S.M.,Stewart, N.K.,Oakley, M.G.,Berger, J.M.
Structural basis for the MukB-topoisomerase IV interaction and its functional implications in vivo.
Embo J., 32:2950-2962, 2013

PubMed Abstract: Chromosome partitioning in Escherichia coli is assisted by two interacting proteins, topoisomerase (topo) IV and MukB. MukB stimulates the relaxation of negative supercoils by topo IV; to understand the mechanism of their action and to define this functional interplay, we determined the crystal structure of a minimal MukB-topo IV complex to 2.3 Å resolution. The structure shows that the so-called 'hinge' region of MukB forms a heterotetrameric assembly with a C-terminal DNA binding domain (CTD) on topo IV's ParC subunit. Biochemical studies show that the hinge stimulates topo IV by competing for a site on the CTD that normally represses activity on negatively supercoiled DNA, while complementation tests using mutants implicated in the interaction reveal that the cellular dependency on topo IV derives from a joint need for both strand passage and MukB binding. Interestingly, the configuration of the MukB·topo IV complex sterically disfavours intradimeric interactions, indicating that the proteins may form oligomeric arrays with one another, and suggesting a framework by which MukB and topo IV may collaborate during daughter chromosome disentanglement.

PubMed: 24097060
DOI: 10.1038/emboj.2013.218

Experimental method

X-RAY DIFFRACTION (2.3 Å)