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Lookup NU author(s): Dr Aurelie Guyet, Dr Frederic SchrammORCiD, Dr Stepan FenykORCiD, Dr Charles WinterhalterORCiD, Professor Heath MurrayORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
DNA replication is initiated at specific chromosomal loci termed origins. In bacteria, the master replication initiation protein DnaA unwinds the origin (oriC), allowing a pair of replicative helicases to be loaded around each strand of the DNA duplex. The molecular mechanisms for managing bacterial helicase loading at oriC are unclear. Here we have investigated the role of the essential accessory helicase loader DnaB in Bacillus subtilis. By identifying and characterizing DnaB residues that are critical for its role during DNA replication initiation, we have located three necessary protein–protein interactions that DnaB makes with initiation proteins DnaA, DnaD, and DnaI. Combining single particle cryo-electron microscopy, AlphaFold3 predictions, and two-hybrid interaction analyses, the data suggests that DnaB acts as an interaction hub to orchestrate dual helicase loading at the origin. We propose a model for DNA replication initiation in B. subtilis and related Firmicutes pathogens that employ DnaB-type helicase loaders.
Author(s): Guyet A, Ruiz Campoy R, Manja P, Schramm FD, Pelliciari S, Fenyk S, Li Y, Winterhalter C, Ilangovan A, Murray H
Publication type: Article
Publication status: Published
Journal: Nucleic Acids Research
Year: 2026
Volume: 54
Issue: 12
Print publication date: 08/07/2026
Online publication date: 02/07/2026
Acceptance date: 09/06/2026
Date deposited: 17/07/2026
ISSN (electronic): 1362-4962
Publisher: Oxford University Press
URL: https://doi.org/10.1093/nar/gkag630
DOI: 10.1093/nar/gkag630
Data Access Statement: All plasmids and strains are available upon request. The ex- perimental cryo-EM map and corresponding atomic model have been deposited in the Electron Microscopy Data Bank (EMDB) and the Protein Data Bank (PDB), respectively, un- der accession codes EMDB EMD-57240 and PDB DOI https:// doi.org/10.2210/pdb29km/pdb . Structural models have been deposited in the ModelArchive ( https://modelarchive.org/) repository: DnaB tetramer (ma-k2gxa), DnaB–DnaA PPI (ma- nocqz), DnaB–DnaD PPI (ma-9osww), DnaB–DnaI PPI (ma- l1wpm), Hybrid cryoEM-AlphaFold3 PPI (ma-v3shm)
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