2I0Q

Crystal structure of a telomere single-strand DNA-protein complex from O. nova with full-length alpha and beta telomere proteins


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.243 
  • R-Value Observed: 0.245 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structural reorganization and the cooperative binding of single-stranded telomere DNA in Sterkiella nova.

Buczek, P.Horvath, M.P.

(2006) J Biol Chem 281: 40124-40134

  • DOI: 10.1074/jbc.M607749200
  • Primary Citation of Related Structures:  
    2I0Q

  • PubMed Abstract: 
  • In Sterkiella nova, alpha and beta telomere proteins bind cooperatively with single-stranded DNA to form a ternary alpha.beta.DNA complex. Association of telomere protein subunits is DNA-dependent, and alpha-beta association enhances DNA affinity. To further understand the molecular basis for binding cooperativity, we characterized several possible stepwise assembly pathways using isothermal titration calorimetry ...

    In Sterkiella nova, alpha and beta telomere proteins bind cooperatively with single-stranded DNA to form a ternary alpha.beta.DNA complex. Association of telomere protein subunits is DNA-dependent, and alpha-beta association enhances DNA affinity. To further understand the molecular basis for binding cooperativity, we characterized several possible stepwise assembly pathways using isothermal titration calorimetry. In one path, alpha and DNA first form a stable alpha.DNA complex followed by the addition of beta in a second step. Binding energy accumulates with nearly equal free energy of association for each of these steps. Heat capacity is nonetheless dramatically different, with DeltaCp = -305 +/- 3 cal mol(-1) K(-1) for alpha binding with DNA and DeltaCp = -2010 +/- 20 cal mol(-1) K(-1) for the addition of beta to complete the alpha.beta.DNA complex. By examining alternate routes including titration of single-stranded DNA with a preformed alpha.beta complex, a significant portion of binding energy and heat capacity could be assigned to structural reorganization involving protein-protein interactions and repositioning of the DNA. Structural reorganization probably affords a mechanism to regulate high affinity binding of telomere single-stranded DNA with important implications for telomere biology. Regulation of telomere complex dissociation is thought to involve post-translational modifications in the lysine-rich C-terminal portion of beta. We observed no difference in binding energetics or crystal structure when comparing complexes prepared with full-length beta or a C-terminally truncated form, supporting interesting parallels between the intrinsically disordered regions of histones and this portion of beta.


    Related Citations: 
    • Crystal structure of the Oxytricha nova telomere end binding protein complexed with single strand DNA
      Horvath, M.P., Schweiker, V.L., Bevilacqua, J.M., Ruggles, J.A., Schultz, S.C.
      (1998) Cell 95: 963
    • DNA G-quartets in a 1.86 A resolution structure of an Oxytricha nova telomeric protein-DNA complex
      Horvath, M.P., Schultz, S.C.
      (2001) J Mol Biol 310: 367

    Organizational Affiliation

    Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA.



Macromolecules

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Telomere-binding protein alpha subunitB [auth A]495Sterkiella novaMutation(s): 0 
Gene Names: MAC-56AMAC-56KMAC-56S
UniProt
Find proteins for P29549 (Sterkiella nova)
Explore P29549 
Go to UniProtKB:  P29549
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UniProt GroupP29549
Protein Feature View
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  • Reference Sequence
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Telomere-binding protein beta subunitC [auth B]385Sterkiella novaMutation(s): 0 
Gene Names: MAC-41AMAC-41S
UniProt
Find proteins for P16458 (Sterkiella nova)
Explore P16458 
Go to UniProtKB:  P16458
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UniProt GroupP16458
Protein Feature View
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  • Reference Sequence

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Entity ID: 1
MoleculeChainsLengthOrganismImage
5'-D(*GP*GP*GP*TP*TP*TP*TP*GP*GP*GP*G)-3'A [auth D]11N/A
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.243 
  • R-Value Observed: 0.245 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 93.331α = 90
b = 93.331β = 90
c = 423.779γ = 120
Software Package:
Software NamePurpose
ADSCdata collection
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-08-22
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance