Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction

Global Symmetry: Helical - H  (3D View)
Global Stoichiometry: Homo 6-mer - A6 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 33.52 kDa 
• Atom Count: 1921 
• Modelled Residue Count: 239 
• Deposited Residue Count: 296 
• Unique protein chains: 1

1CR2

CRYSTAL STRUCTURE OF THE HELICASE DOMAIN OF THE GENE 4 PROTEIN OF BACTERIOPHAGE T7: COMPLEX WITH DATP

• PDB DOI: 10.2210/pdb1CR2/pdb

• Classification: TRANSFERASE
• Organism(s): Escherichia phage T7
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 1999-08-12 Released: 1999-11-10 
• Deposition Author(s): Sawaya, M.R., Guo, S., Tabor, S., Richardson, C.C., Ellenberger, T.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.296 
• R-Value Work: 0.245 
• R-Value Observed: 0.250 

Literature

Crystal structure of the helicase domain from the replicative helicase-primase of bacteriophage T7.

Sawaya, M.R., Guo, S., Tabor, S., Richardson, C.C., Ellenberger, T.

(1999) Cell 99: 167-177

• PubMed: 10535735 
• DOI: 10.1016/s0092-8674(00)81648-7
• Primary Citation of Related Structures:  
  1CR0, 1CR1, 1CR2, 1CR4


• PubMed Abstract: 
  

Helicases that unwind DNA at the replication fork are ring-shaped oligomeric enzymes that move along one strand of a DNA duplex and catalyze the displacement of the complementary strand in a reaction that is coupled to nucleotide hydrolysis. The helicase domain of the replicative helicase-primase protein from bacteriophage T7 crystallized as a helical filament that resembles the Escherichia coli RecA protein, an ATP-dependent DNA strand exchange factor. When viewed in projection along the helical axis of the crystals, six protomers of the T7 helicase domain resemble the hexameric rings seen in electron microscopic images of the intact T7 helicase-primase. Nucleotides bind at the interface between pairs of adjacent subunits where an arginine is near the gamma-phosphate of the nucleotide in trans. The bound nucleotide stabilizes the folded conformation of a DNA-binding motif located near the center of the ring. These and other observations suggest how conformational changes are coupled to DNA unwinding activity.

---

Organizational Affiliation: 

Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
DNA PRIMASE/HELICASE	A	296	Escherichia phage T7	Mutation(s): 1  Gene Names: 4 EC: 2.7.7 (PDB Primary Data), 3.6.4.12 (UniProt)
UniProt
Find proteins for P03692 (Escherichia phage T7) Explore P03692  Go to UniProtKB:  P03692

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
DTP	D [auth A]	2'-DEOXYADENOSINE 5'-TRIPHOSPHATE C10 H16 N5 O12 P3 SUYVUBYJARFZHO-RRKCRQDMSA-N
SO4	B [auth A], C [auth A]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.296 
• R-Value Work: 0.245 
• R-Value Observed: 0.250 
• Space Group: P 6₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 80.172	α = 90
b = 80.172	β = 90
c = 85.709	γ = 120

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	refinement
DENZO	data reduction
SCALEPACK	data scaling
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1999-08-12 
• Released Date: 1999-11-10 
Deposition Author(s): Sawaya, M.R., Guo, S., Tabor, S., Richardson, C.C., Ellenberger, T.

Revision History  

• Version 1.0: 1999-11-10
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2021-11-03
  Changes: Database references, Derived calculations