Biological Assembly 1  

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

Global Symmetry: Cyclic - C6  (3D View)
Global Stoichiometry: Homo 6-mer - A6 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 60.08 kDa 
• Atom Count: 4295 
• Modelled Residue Count: 499 
• Deposited Residue Count: 558 
• Unique protein chains: 1

1OLO

Hexameric Replicative DNA Helicase RepA from Plasmid RSF1010 - Cubic Crystal Structure

• PDB DOI: 10.2210/pdb1OLO/pdb

• Classification: TRANSCRIPTION
• Organism(s): Escherichia coli
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2003-08-08 Released: 2003-09-19 
• Deposition Author(s): Niedenzu, T., Saenger, W.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.55 Å
• R-Value Free: 0.211 
• R-Value Work: 0.176 

Literature

Hexameric Rsf1010 Helicase Repa: The Structural and Functional Importance of Single Amino Acid Residues

Ziegelin, G., Niedenzu, T., Lurz, R., Saenger, W., Lanka, E.

(2003) Nucleic Acids Res 31: 5917

• PubMed: 14530440 
• DOI: 10.1093/nar/gkg790
• Primary Citation of Related Structures:  
  1OLO


• PubMed Abstract: 
  

In the known monoclinic crystals the 3-dimensional structure of the hexameric, replicative helicase RepA encoded by plasmid RSF1010 shows 6-fold rotational symmetry. In contrast, in the cubic crystal form at 2.55 A resolution described here RepA has 3-fold symmetry and consists of a trimer of dimers. To study structure-function relationships, a series of repA deletion mutants and mutations yielding single amino acid exchanges were constructed and the respective gene products were analyzed in vivo and in vitro. Hexamerization of RepA occurs via the N-terminus and is required for NTP hydrolysis. The C-terminus is essential both for the interaction with the replication machinery and for the helicase activity. Functional analyses of RepA variants with single amino acid exchanges confirmed most of the predictions that were based on the published 3-dimensional structure. Of the five motifs conserved in family 4 helicases, all residues conserved in RepA and T7 gp4 helicases participate in DNA unwinding. Residues K42, E76, D77, D139 and H178, proposed to play key roles in catalyzing the hydrolysis of NTPs, are essential for RepA activity. Residue H178 of motif H3 couples nucleotide consumption to DNA strand separation.

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Organizational Affiliation: 

Max-Planck-Institut für Molekulare Genetik, Ihnestrasse 73, Dahlem, D-14195 Berlin, Germany.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
REGULATORY PROTEIN REPA	A, B	279	Escherichia coli	Mutation(s): 0  Gene Names: repA
UniProt
Find proteins for P20356 (Escherichia coli) Explore P20356  Go to UniProtKB:  P20356

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	C [auth A], D [auth B]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.55 Å
• R-Value Free: 0.211 
• R-Value Work: 0.176 
• Space Group: P 4₃ 3 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 190.293	α = 90
b = 190.293	β = 90
c = 190.293	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
DENZO	data reduction
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2003-08-08 
• Released Date: 2003-09-19 
Deposition Author(s): Niedenzu, T., Saenger, W.

Revision History  

• Version 1.0: 2003-09-19
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Advisory, Version format compliance
• Version 1.2: 2017-06-28
  Changes: Data collection
• Version 1.3: 2019-05-08
  Changes: Data collection, Experimental preparation
• Version 1.4: 2019-05-22
  Changes: Data collection, Experimental preparation