Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Distinct Quaternary States, Intermediates, and Autoinhibition During Loading of the DnaB-Replicative Helicase by the Phage λP Helicase Loader.
Journal, issue, pages	bioRxiv, Year 2025
Publish date	Jun 2, 2025
Authors	Abhipsa Shatarupa / Dhanjai Brown / Paul Dominic B Olinares / Jillian Chase / Eta Isiorho / Brian T Chait / David Jeruzalmi
PubMed Abstract	Replicative helicases require loader proteins for assembly at the origins of DNA replication. Multiple copies of the bacteriophage λP (P) loader bind to and load the DnaB (B) replicative helicase ...Replicative helicases require loader proteins for assembly at the origins of DNA replication. Multiple copies of the bacteriophage λP (P) loader bind to and load the DnaB (B) replicative helicase on replication-origin-derived single-stranded DNA. We find that the DnaB•λP complex exists in two forms: B P and B P . In the 2.66 Å cryo-EM model of B P , five copies of the λP loader assemble into a crown-like shape that tightly grips DnaB. In this complex, closed planar DnaB is reconfigured into an open spiral with a sufficiently sized breach to permit ssDNA to enter an internal chamber. The transition to the open spiral involves λP-mediated changes to the Docking Helix (DH)-Linker Helix (LH) interface. The loader directly stabilizes the open spiral. Unexpectedly, one λP chain in B P is bound across the breach, precluding entry of replication-origin-derived ssDNA into DnaB's central chamber. We suggest that the B P complex is an early intermediate in the helicase activation pathway wherein neither the DnaB helicase nor the λP loader has attained its final form. DnaB in this complex adopts a partially open planar configuration, termed ajar planar. The partially ordered λP loader assembly features a much looser interaction with DnaB. The ssDNA and ATP sites in both complexes are in a configuration ill-suited for binding or hydrolysis. Our work specifies the conformational changes required for the intermediate B P to transition to B P on the pathway to recruitment by the initiator protein complex to the replication origin.
External links	bioRxiv / PubMed:40501539 / PubMed Central
Methods	EM (single particle) / X-ray diffraction
Resolution	1.86 - 3.85 Å
Structure data	70269 9oa1 EMDB-70269, PDB-9oa1: Ecoli DnaB helicase and Phage Lambda loader P with ADP-Mg in a 6:5 stoichiometry ratio. Method: EM (single particle) / Resolution: 2.66 Å 70271 9oa2 EMDB-70271, PDB-9oa2: Ecoli DnaB helicase and Phage Lambda loader P with ADP-Mg in a 6:6 stoichiometry ratio. Method: EM (single particle) / Resolution: 3.85 Å PDB-8v9s: Distinct Quaternary States, Intermediates, and Autoinhibition During Loading of the DnaB-Replicative Helicase by the Phage Lambda P Helicase Loader Method: X-RAY DIFFRACTION / Resolution: 1.86 Å
Chemicals	ChemComp-HOH: WATER ChemComp-ADP: ADENOSINE-5'-DIPHOSPHATE / ADP, energy-carrying moleculeYM ChemComp-MG*: Unknown entry
Source	escherichia coli (E. coli) escherichia phage lambda (virus)
Keywords	REPLICATION / hexameric DnaB helicase / replicative loader / Phage Lambda P helicase loader / bacterial DNA replication initiation / DNA BINDING PROTEIN / auto inhibition / bacterial DNA replication initiation intermediate