Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Observed: 0.178 

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Structure of a B-DNA dodecamer: conformation and dynamics.

Drew, H.R.Wing, R.M.Takano, T.Broka, C.Tanaka, S.Itakura, K.Dickerson, R.E.

(1981) Proc Natl Acad Sci U S A 78: 2179-2183

  • DOI: https://doi.org/10.1073/pnas.78.4.2179
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The crystal structure of the synthetic DNA dodecamer d(CpGpCpGpApApTpTpCpGpCpG) has been refined to a residual error of R = 17.8% at 1.9-A resolution (two-sigma data). The molecule forms slightly more than one complete turn of right-handed double-stranded B helix. The two ends of the helix overlap and interlock minor grooves with neighboring molecules up and down a 2(1) screw axis, producing a 19 degrees bend in helix axis over the 11-base-pair steps of the dodecamer. In the center of the molecule, where perturbation is least, the helix has a mean rotation of 36.9 degrees per step, or 9.8 base pairs per turn. The mean propeller twist (total dihedral angle between base planes) between A . T base pairs in the center of the molecule is 17.3 degrees, and that between C . G pairs on the two ends averages 11.5 degrees. Individual deoxyribose ring conformations as measured by the C5'-C4'-C3'-O3' torsion angle delta, exhibit an approximately Gaussian distribution centered around the C1'-exo position with delta avg = 123 degrees and a range of 79 degrees to 157 degrees. Purine sugars cluster at high delta values, and pyrimidine sugars cluster at lower delta. A tendency toward 2-fold symmetry in sugar conformation about the center of the molecule is detectable in spite of the destruction of ideal 2-fold symmetry by the molecular bending. More strikingly, sugar conformations of paired based appear to follow a "principle of anticorrelation," with delta values lying approximately the same distance to either side of the center value, delta = 123 degrees. This same anticorrelation is also observed in other DNA and DNA . RNA structures.


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Entity ID: 1
MoleculeChains LengthOrganismImage
A, B
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 24.87α = 90
b = 40.39β = 90
c = 66.2γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1981-05-21
    Type: Initial release
  • Version 1.1: 2008-05-22
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-07
    Changes: Data collection, Database references