1Q57

The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.45 Å
  • R-Value Free: 0.326 
  • R-Value Work: 0.299 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The Crystal Structure of the Bifunctional Primase-Helicase of Bacteriophage T7

Toth, E.A.Li, Y.Sawaya, M.R.Cheng, Y.Ellenberger, T.

(2003) Mol.Cell 12: 1113-1123


  • PubMed Abstract: 
  • Within minutes after infecting Escherichia coli, bacteriophage T7 synthesizes many copies of its genomic DNA. The lynchpin of the T7 replication system is a bifunctional primase-helicase that unwinds duplex DNA at the replication fork while initiatin ...

    Within minutes after infecting Escherichia coli, bacteriophage T7 synthesizes many copies of its genomic DNA. The lynchpin of the T7 replication system is a bifunctional primase-helicase that unwinds duplex DNA at the replication fork while initiating the synthesis of Okazaki fragments on the lagging strand. We have determined a 3.45 A crystal structure of the T7 primase-helicase that shows an articulated arrangement of the primase and helicase sites. The crystallized primase-helicase is a heptamer with a crown-like shape, reflecting an intimate packing of helicase domains into a ring that is topped with loosely arrayed primase domains. This heptameric isoform can accommodate double-stranded DNA in its central channel, which nicely explains its recently described DNA remodeling activity. The double-jointed structure of the primase-helicase permits a free range of motion for the primase and helicase domains that suggests how the continuous unwinding of DNA at the replication fork can be periodically coupled to Okazaki fragment synthesis.


    Organizational Affiliation

    Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DNA primase/helicase
A, B, C, D, E, F, G
503Enterobacteria phage T7EC: 3.6.4.12, 2.7.7.-
Find proteins for P03692 (Enterobacteria phage T7)
Go to UniProtKB:  P03692
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.45 Å
  • R-Value Free: 0.326 
  • R-Value Work: 0.299 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 117.179α = 90.00
b = 171.567β = 99.86
c = 118.581γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
HKL-2000data reduction
SHARPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-11-25
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Version format compliance