Crystal structure of the Thermus aquaticus DnaB monomer

Experimental Data Snapshot

  • Resolution: 2.90 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.241 
  • R-Value Observed: 0.243 

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The crystal structure of the Thermus aquaticus DnaB helicase monomer.

Bailey, S.Eliason, W.K.Steitz, T.A.

(2007) Nucleic Acids Res 35: 4728-4736

  • DOI: https://doi.org/10.1093/nar/gkm507
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The ring-shaped hexameric DnaB helicase unwinds duplex DNA at the replication fork of eubacteria. We have solved the crystal structure of the full-length Thermus aquaticus DnaB monomer, or possibly dimer, at 2.9 A resolution. DnaB is a highly flexible two domain protein. The C-terminal domain exhibits a RecA-like core fold and contains all the conserved sequence motifs that are characteristic of the DnaB helicase family. The N-terminal domain contains an additional helical hairpin that makes it larger than previously appreciated. Several DnaB mutations that modulate its interaction with primase are found in this hairpin. The similarity in the fold of the DnaB N-terminal domain with that of the C-terminal helicase-binding domain (HBD) of the DnaG primase also includes this hairpin. Comparison of hexameric homology models of DnaB with the structure of the papillomavirus E1 helicase suggests the two helicases may function through different mechanisms despite their sharing a common ancestor.

  • Organizational Affiliation

    Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DnaB replication fork helicase
A, B, C, D
444Thermus aquaticusMutation(s): 0 
Gene Names: dnab
EC: 3.6.1
Find proteins for Q9Z693 (Thermus aquaticus)
Explore Q9Z693 
Go to UniProtKB:  Q9Z693
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9Z693
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.90 Å
  • R-Value Free: 0.285 
  • R-Value Work: 0.241 
  • R-Value Observed: 0.243 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 104.707α = 90
b = 104.707β = 90
c = 363.258γ = 120
Software Package:
Software NamePurpose
CBASSdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-24
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2024-02-21
    Changes: Data collection, Database references, Derived calculations