287D

X-RAY AND SOLUTION STUDIES OF DNA OLIGOMERS AND IMPLICATIONS FOR THE STRUCTURAL BASIS OF A-TRACT-DEPENDENT CURVATURE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Observed: 0.150 

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This is version 1.2 of the entry. See complete history


Literature

X-ray and solution studies of DNA oligomers and implications for the structural basis of A-tract-dependent curvature.

Shatzky-Schwartz, M.Arbuckle, N.D.Eisenstein, M.Rabinovich, D.Bareket-Samish, A.Haran, T.E.Luisi, B.F.Shakked, Z.

(1997) J Mol Biol 267: 595-623

  • DOI: 10.1006/jmbi.1996.0878
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • DNA containing short periodic stretches of adenine residues (known as A-tracts), which are aligned with the helical repeat, exhibit a pronounced macroscopic curvature. This property is thought to arise from the cumulative effects of a distinctive str ...

    DNA containing short periodic stretches of adenine residues (known as A-tracts), which are aligned with the helical repeat, exhibit a pronounced macroscopic curvature. This property is thought to arise from the cumulative effects of a distinctive structure of the A-tract. It has also been observed by gel electrophoresis that macroscopic curvature is largely retained when inosine bases are introduced singly into A-tracts but decreases abruptly for pure I-tracts. The structural basis of this effect is unknown. Here we describe X-ray and gel electrophoretic analyses of several oligomers incorporating adenine or inosine bases or both. We find that macroscopic curvature is correlated with a distinctive base-stacking geometry characterized by propeller twisting of the base-pairs. Regions of alternating adenine and inosine bases display large propeller twisting comparable to that of pure A-tracts, whereas the values observed for pure I-tracts are significantly smaller. We also observe in the crystal structures that propeller twist leads to close cross-strand contacts between amino groups from adenine and cytosine bases, indicating an attractive NH-N interaction, which is analogous to the NH-O interaction proposed for A-tracts. This interaction also occurs between adenine bases across an A-T step and may explain in part the different behavior of A-T versus T-A steps in the context of A-tract-induced curvature. We also note that hydration patterns may contribute to propeller-twisted conformation. Based on the present data and other structural and biophysical studies, we propose that DNA macroscopic curvature is related to the structural invariance of A-tract and A-tract-like regions conferred by high propeller twist, cross-strand interactions and characteristic hydration. The implications of these findings to the mechanism of DNA bending are discussed.


    Organizational Affiliation

    Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.



Macromolecules
  • Find similar nucleic acids by: Sequence   |   Structure
Entity ID: 1
MoleculeChainsLengthOrganism
DNA (5'-D(*CP*GP*CP*GP*AP*TP*AP*TP*CP*GP*CP*G)-3')A, B12N/A
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Observed: 0.150 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 24.279α = 90
b = 39.355β = 90
c = 66.37γ = 90
Software Package:
Software NamePurpose
NUCLSQrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1997-05-08
    Type: Initial release
  • Version 1.1: 2008-05-22
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance