NMR solution structure of the N-terminal domain of the DNA polymerase alpha p68 subunit

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the least restraint violations 

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Structure of a DNA polymerase alpha-primase domain that docks on the SV40 helicase and activates the viral primosome.

Huang, H.Weiner, B.E.Zhang, H.Fuller, B.E.Gao, Y.Wile, B.M.Zhao, K.Arnett, D.R.Chazin, W.J.Fanning, E.

(2010) J Biol Chem 285: 17112-17122

  • DOI: https://doi.org/10.1074/jbc.M110.116830
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    DNA polymerase alpha-primase (pol-prim) plays a central role in DNA replication in higher eukaryotes, initiating synthesis on both leading and lagging strand single-stranded DNA templates. Pol-prim consists of a primase heterodimer that synthesizes RNA primers, a DNA polymerase that extends them, and a fourth subunit, p68 (also termed B-subunit), that is thought to regulate the complex. Although significant knowledge about single-subunit primases of prokaryotes has accumulated, the functions and regulation of pol-prim remain poorly understood. In the SV40 replication model, the p68 subunit is required for primosome activity and binds directly to the hexameric viral helicase T antigen, suggesting a functional link between T antigen-p68 interaction and primosome activity. To explore this link, we first mapped the interacting regions of the two proteins and discovered a previously unrecognized N-terminal globular domain of p68 (p68N) that physically interacts with the T antigen helicase domain. NMR spectroscopy was used to determine the solution structure of p68N and map its interface with the T antigen helicase domain. Structure-guided mutagenesis of p68 residues in the interface diminished T antigen-p68 interaction, confirming the interaction site. SV40 primosome activity of corresponding pol-prim mutants decreased in proportion to the reduction in p68N-T antigen affinity, confirming that p68-T antigen interaction is vital for primosome function. A model is presented for how this interaction regulates SV40 primosome activity, and the implications of our findings are discussed in regard to the molecular mechanisms of eukaryotic DNA replication initiation.

  • Organizational Affiliation

    Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37232, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA polymerase subunit alpha B101Homo sapiensMutation(s): 0 
Gene Names: POLA2
UniProt & NIH Common Fund Data Resources
Find proteins for Q14181 (Homo sapiens)
Explore Q14181 
Go to UniProtKB:  Q14181
GTEx:  ENSG00000014138 
Entity Groups  
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UniProt GroupQ14181
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the least restraint violations 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-02-02
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2022-03-16
    Changes: Data collection, Database references, Derived calculations