1G8Y

CRYSTAL STRUCTURE OF THE HEXAMERIC REPLICATIVE HELICASE REPA OF PLASMID RSF1010

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.221 

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This is version 1.2 of the entry. See complete history. 


Literature

Crystal structure of the hexameric replicative helicase RepA of plasmid RSF1010.

Niedenzu, T., Roleke, D., Bains, G., Scherzinger, E., Saenger, W.

(2001) J Mol Biol 306: 479-487

  • DOI: 10.1006/jmbi.2000.4398
  • Primary Citation of Related Structures:  
    1G8Y

  • PubMed Abstract: 

    • Unwinding of double-stranded DNA into single-stranded intermediates required for various fundamental life processes is catalyzed by helicases, a family of mono-, di- or hexameric motor proteins fueled by nucleoside triphosphate hydrolysis. The three-dimensional crystal structure of the hexameric helicase RepA encoded by plasmid RSF1010 has been determined by X-ray diffraction at 2 ...

    Unwinding of double-stranded DNA into single-stranded intermediates required for various fundamental life processes is catalyzed by helicases, a family of mono-, di- or hexameric motor proteins fueled by nucleoside triphosphate hydrolysis. The three-dimensional crystal structure of the hexameric helicase RepA encoded by plasmid RSF1010 has been determined by X-ray diffraction at 2.4 A resolution. The hexamer shows an annular structure with 6-fold rotational symmetry and a approximately 17 A wide central hole, suggesting that single-stranded DNA may be threaded during unwinding. Homologs of all five conserved sequence motifs of the DnaB-like helicase family are found in RepA, and the topography of the monomer resembles RecA and the helicase domain of the bacteriophage T7 gp4 protein. In a modeled complex, ATP molecules are located at the subunit interfaces and clearly define adenine-binding and ATPase catalytic sites formed by amino acid residues located on adjacent monomers; most remarkable is the "arginine finger" Arg207 contributing to the active site in the adjacent monomer. This arrangement of active-site residues suggests cooperativity between monomers in ATP hydrolysis and helicase activity of RepA. The mechanism of DNA unwinding remains elusive, as RepA is 6-fold symmetric, contrasting the recently published asymmetric structure of the bacteriophage T7 gp4 helicase domain.

    Organizational Affiliation: 

    Institut für Kristallographie, Freie Universität Berlin, Takustr. 6, Berlin, D-14195, Germany.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
REGULATORY PROTEIN REPA
A, B, C, D, E, F, G, H, I, J, K, L
A, B, C, D, E, F, G, H, I, J, K, L
279Escherichia coliMutation(s): 0 
Gene Names: REPA ON PLASMID INCQ RSF1010, repA
UniProt
Find proteins for P20356 (Escherichia coli)
Explore P20356 
Go to UniProtKB:  P20356
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP20356
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.221 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 104.432α = 90
b = 179.156β = 108.8
c = 116.289γ = 90
Software Package:
Software NamePurpose
MLPHAREphasing
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-02-14
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance