4E2I

The Complex Structure of the SV40 Helicase Large T Antigen and p68 Subunit of DNA Polymerase Alpha-Primase

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 5.00 Å
  • R-Value Free: 0.314 
  • R-Value Work: 0.305 
  • R-Value Observed: 0.305 

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This is version 1.1 of the entry. See complete history. 


Literature

Structural basis for the interaction of a hexameric replicative helicase with the regulatory subunit of human DNA polymerase alpha-primase.

Zhou, B., Arnett, D.R., Yu, X., Brewster, A., Sowd, G.A., Xie, C.L., Vila, S., Gai, D., Fanning, E., Chen, X.S.

(2012) J Biol Chem 287: 26854-26866

  • DOI: 10.1074/jbc.M112.363655
  • Primary Citation of Related Structures:  
    4E2I

  • PubMed Abstract: 

    • DNA polymerase α-primase (Pol-prim) plays an essential role in eukaryotic DNA replication, initiating synthesis of the leading strand and of each Okazaki fragment on the lagging strand. Pol-prim is composed of a primase heterodimer that synthesizes an RNA primer, a DNA polymerase subunit that extends the primer, and a regulatory B-subunit (p68) without apparent enzymatic activity ...

    DNA polymerase α-primase (Pol-prim) plays an essential role in eukaryotic DNA replication, initiating synthesis of the leading strand and of each Okazaki fragment on the lagging strand. Pol-prim is composed of a primase heterodimer that synthesizes an RNA primer, a DNA polymerase subunit that extends the primer, and a regulatory B-subunit (p68) without apparent enzymatic activity. Pol-prim is thought to interact with eukaryotic replicative helicases, forming a dynamic multiprotein assembly that displays primosome activity. At least three subunits of Pol-prim interact physically with the hexameric replicative helicase SV40 large T antigen, constituting a simple primosome that is active in vitro. However, structural understanding of these interactions and their role in viral chromatin replication in vivo remains incomplete. Here, we report the detailed large T antigen-p68 interface, as revealed in a co-crystal structure and validated by site-directed mutagenesis, and we demonstrate its functional importance in activating the SV40 primosome in cell-free reactions with purified Pol-prim, as well as in monkey cells in vivo.

    Organizational Affiliation: 

    Department of Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089, USA.



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Large T antigenA, B, C, D, E, F, G, H, A,  B,  C,  D,  E,  F,  G,  H,  I,  J,  K,  L
362Macaca mulatta polyomavirus 1Mutation(s): 0 
EC: 3.6.4
Find proteins for P03070 (Simian virus 40)
Explore P03070 
Go to UniProtKB:  P03070
Protein Feature View
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  • Reference Sequence
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(by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
DNA polymerase alpha subunit B1, 2, 3, 4, 5, 6, 7, 8, 1,  2,  3,  4,  5,  6,  7,  8,  9,  U,  W
78Homo sapiensMutation(s): 0 
Gene Names: POLA2
Find proteins for Q14181 (Homo sapiens)
Explore Q14181 
Go to UniProtKB:  Q14181
NIH Common Fund Data Resources
PHAROS:  Q14181
GTEx:  ENSG00000014138
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 5.00 Å
  • R-Value Free: 0.314 
  • R-Value Work: 0.305 
  • R-Value Observed: 0.305 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 249.098α = 90
b = 249.098β = 90
c = 387.032γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
CCP4model building
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CCP4phasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-06-13
    Type: Initial release
  • Version 1.1: 2013-08-28
    Changes: Database references