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	Nucleic Acids Res, Vol. 53, Issue 22, Year 2025
Publish date	Nov 26, 2025
Authors	Abhipsa Shatarupa / Dhanjai Brown / Paul Dominic B Olinares / Jillian Chase / Eta Isiorho / Brian T Chait / David Jeruzalmi /
PubMed Abstract	Replicative helicases need loader proteins to assemble at DNA replication origins. Multiple copies of the bacteriophage λP (P) loader bind and load the Escherichia coli DnaB (B) replicative helicase ...Replicative helicases need loader proteins to assemble at DNA replication origins. Multiple copies of the bacteriophage λP (P) loader bind and load the Escherichia coli DnaB (B) replicative helicase onto single-stranded (ss) DNA from the replication origin. We find that the E. coli DnaB•λP complex exists in two forms: B6P5 and B6P6. In the 2.66 Å cryo-EM structure of B6P5, five λP loader copies form a crown-like shape that tightly grips DnaB. In this complex, the closed, planar DnaB is reconfigured into an open spiral with a large enough breach to allow ssDNA to enter an internal chamber. Transition to the open spiral involves λP-induced changes to the Docking Helix (DH)-Linker Helix (LH) interface. Unexpectedly, one λP chain in B6P5 is positioned across the breach. The disposition of this λP chain implies a complex pathway for entry of a replication-origin-derived ssDNA "bubble" ssDNA into the B6P5 complex. We propose that the B6P6 complex is an early intermediate in helicase activation in which neither DnaB nor λP has reached its final form. In this complex, DnaB adopts a partially open, ajar planar configuration. λP in B6P6 interacts more loosely with DnaB. The ssDNA- and ATP-binding sites in both complexes are not correctly configured for binding or hydrolysis. Our findings detail the distinct conformations of B6P6 and B6P5, allowing us to propose a structural model for the transition from an ajar planar to an open spiral configuration in the helicase loading pathway.
External links	Nucleic Acids Res / PubMed:41312769 / PubMed Central
Methods	EM (single particle) / X-ray diffraction
Resolution	1.86 - 3.85 Å
Structure data	43082 8v9t EMDB-43082, PDB-8v9t: Ecoli DnaB helicase and Phage Lambda loader P with ADP-Mg in a 6:5 stoichiometry ratio Method: EM (single particle) / Resolution: 2.84 Å 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