9GM7

MukBEF in a nucleotide-bound state with open neck gate (monomer)

Summary for 9GM7

• Entry DOI: 10.2210/pdb9gm7/pdb
• EMDB information: 51443
• Descriptor: Chromosome partition protein MukF, Chromosome partition protein MukE, Acyl carrier protein, ... (6 entities in total)
• Functional Keywords: smc complex, chromosome segregation, abc-type atpase, dna binding protein
• Biological source: Photorhabdus thracensis; More
• Total number of polymer chains: 8
• Total formula weight: 514751.21

Authors

Burmann, F.,Lowe, J. (deposition date: 2024-08-28, release date: 2025-03-26, Last modification date: 2025-05-14)

Primary citation

Burmann, F.,Clifton, B.,Koekemoer, S.,Wilkinson, O.J.,Kimanius, D.,Dillingham, M.S.,Lowe, J.
Mechanism of DNA capture by the MukBEF SMC complex and its inhibition by a viral DNA mimic.
Cell, 188:2465-, 2025

PubMed Abstract: Ring-like structural maintenance of chromosome (SMC) complexes are crucial for genome organization and operate through mechanisms of DNA entrapment and loop extrusion. Here, we explore the DNA loading process of the bacterial SMC complex MukBEF. Using cryoelectron microscopy (cryo-EM), we demonstrate that ATP binding opens one of MukBEF's three potential DNA entry gates, exposing a DNA capture site that positions DNA at the open neck gate. We discover that the gp5.9 protein of bacteriophage T7 blocks this capture site by DNA mimicry, thereby preventing DNA loading and inactivating MukBEF. We propose a comprehensive and unidirectional loading mechanism in which DNA is first captured at the complex's periphery and then ingested through the DNA entry gate, powered by a single cycle of ATP hydrolysis. These findings illuminate a fundamental aspect of how ubiquitous DNA organizers are primed for genome maintenance and demonstrate how this process can be disrupted by viruses.

PubMed: 40168993
DOI: 10.1016/j.cell.2025.02.032

Experimental method

ELECTRON MICROSCOPY (4.3 Å)