7ZR1 image
Entry Detail
PDB ID:
7ZR1
EMDB ID:
Keywords:
Title:
Chaetomium thermophilum Mre11-Rad50-Nbs1 complex bound to ATPyS (composite structure)
Biological Source:
PDB Version:
Deposition Date:
2022-05-03
Release Date:
2023-01-11
Method Details:
Experimental Method:
Resolution:
4.00 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Double-strand break repair protein
Chain IDs:A, B
Chain Length:730
Number of Molecules:2
Biological Source:Thermochaetoides thermophila
Polymer Type:polypeptide(L)
Description:DH domain-containing protein
Chain IDs:C, D
Chain Length:1315
Number of Molecules:2
Biological Source:Thermochaetoides thermophila
Polymer Type:polypeptide(L)
Description:FHA domain-containing protein
Chain IDs:E
Chain Length:954
Number of Molecules:1
Biological Source:Thermochaetoides thermophila
Primary Citation
Cryo-EM structure of the Mre11-Rad50-Nbs1 complex reveals the molecular mechanism of scaffolding functions.
Mol.Cell 83 167 185.e9 (2023)
PMID: 36577401 DOI: 10.1016/j.molcel.2022.12.003

Abstact

The DNA double-strand break repair complex Mre11-Rad50-Nbs1 (MRN) detects and nucleolytically processes DNA ends, activates the ATM kinase, and tethers DNA at break sites. How MRN can act both as nuclease and scaffold protein is not well understood. The cryo-EM structure of MRN from Chaetomium thermophilum reveals a 2:2:1 complex with a single Nbs1 wrapping around the autoinhibited Mre11 nuclease dimer. MRN has two DNA-binding modes, one ATP-dependent mode for loading onto DNA ends and one ATP-independent mode through Mre11's C terminus, suggesting how it may interact with DSBs and intact DNA. MRNs two 60-nm-long coiled-coil domains form a linear rod structure, the apex of which is assembled by the two joined zinc-hook motifs. Apices from two MRN complexes can further dimerize, forming 120-nm spanning MRN-MRN structures. Our results illustrate the architecture of MRN and suggest how it mechanistically integrates catalytic and tethering functions.

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