Evidence map›Paper›PMID 41521670›Full record

ArticleNucleic acids research2026

Bringing the ends together: cryo-EM structures of mycobacterial Ku in complex with DNA define its role in NHEJ synapsis.

Joydeep Baral, Ching-Seng Ang, Paul James McMillan, Kalyan Shobhana, Ayushi Saini, Elizabeth Hinde, Amit Kumar Das, Isabelle Rouiller

Abstract read
In one paragraph

Article in Nucleic acids research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Joydeep BaralDepartment of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, West Midnapore 721302, West Bengal, India.ORCID 0000-0002-3633-7823
Ching-Seng AngMelbourne Mass Spectrometry and Proteomics Facility, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3052, Australia.
Paul James McMillanDepartment of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia.
Kalyan ShobhanaDepartment of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia.
Ayushi SainiDepartment of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, West Midnapore 721302, West Bengal, India.
Elizabeth HindeSchool of Physics, University of Melbourne, Victoria 3010, Australia.ORCID 0000-0001-8317-1152
Amit Kumar DasDepartment of Bioscience and Biotechnology, Indian Institute of Technology Kharagpur, West Midnapore 721302, West Bengal, India.ORCID 0000-0001-9703-1898
Isabelle RouillerDepartment of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia.ORCID 0000-0002-1288-8575

Funding

Australian Research Council IC200100052National Health and Medical Research Council 2020/GNT2000934Science and Engineering Research Board CRG/2020/002622
6 · The paper itself

Abstract

Non-homologous end joining (NHEJ) is the sole pathway for repairing double-strand breaks in Mycobacterium tuberculosis during dormancy, relying on mycobacterial Ku (mKu) and ligase D, with mKu as the rate-limiting factor. Despite its essential role, the lack of structural information on prokaryotic Ku has hindered understanding of the molecular mechanisms underlying bacterial two-component NHEJ machinery. Here, we present the first cryo-electron microscopy (cryo-EM) structures of mKu in DNA-bound and higher-order supercomplex forms, revealing a Ku-mediated DNA synapsis mechanism unique to prokaryotes. Integrating cryo-EM with hydrogen-deuterium exchange mass spectrometry, we define key mKu-mKu dimerization, DNA-binding, and synapsis interactions essential for efficient NHEJ, bridging structure with function. Structure-guided in silico mutagenesis, coupled with electrophoretic mobility shift assays, identifies residues essential for DNA binding and synaptic assembly, which are crucial for NHEJ. Förster resonance energy transfer confirms DNA-dependent mKu oligomerization in solution, while live-cell imaging captures its spatiotemporal dynamics during double-stranded DNA break repair. These findings provide fundamental insights into the architecture and function of prokaryotic NHEJ, positioning mKu as a potential therapeutic target against tuberculosis and offering a framework for understanding DNA repair across bacterial species.

Indexed as

Bacterial ProteinsDNADNA, BacterialDNA End-Joining RepairKu AutoantigenMycobacterium tuberculosisCryoelectron MicroscopyDNA Breaks, Double-StrandedModels, MolecularProtein BindingProtein MultimerizationBacterial ProteinsDNADNA, BacterialKu Autoantigen

Identifiers

PMID41521670
PMCPMC12784962

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.