Experimental Data Snapshot

  • Resolution: 2.25 Å
  • R-Value Observed: 0.168 

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Conformation of B-DNA containing O6-ethyl-G-C base pairs stabilized by minor groove binding drugs: molecular structure of d(CGC[e6G]AATTCGCG complexed with Hoechst 33258 or Hoechst 33342.

Sriram, M.van der Marel, G.A.Roelen, H.L.van Boom, J.H.Wang, A.H.

(1992) EMBO J 11: 225-232

  • DOI: https://doi.org/10.1002/j.1460-2075.1992.tb05045.x
  • Primary Citation of Related Structures:  
    127D, 128D, 129D, 130D

  • PubMed Abstract: 

    O6-ethyl-G (e6G) is an important DNA lesion, caused by the exposure of cells to alkylating agents such as N-ethyl-N-nitrosourea. A strong correlation exists between persistence of e6G lesion and subsequent carcinogenic conversion. We have determined the three-dimensional structure of a DNA molecule incorporating the e6G lesion by X-ray crystallography. The DNA dodecamer d(CGC[e6G]AATTCGCG), complexed to minor groove binding drugs Hoechst 33258 or Hoechst 33342, has been crystallized in the space group P212121, isomorphous to other related dodecamer DNA crystals. In addition, the native dodecamer d(CGCGAATTCGCG) was crystallized with Hoechst 33342. All three new structures were solved by the molecular replacement method and refined by the constrained least squares procedure to R-factors of approximately 16% at approximately 2.0 A resolution. In the structure of three Hoechst drug-dodecamer complexes in addition to the one published earlier [Teng et al. (1988) Nucleic Acids Res., 16, 2671-2690], the Hoechst molecule lies squarely at the central AATT site with the ends approaching the G4-C21 and the G16-C9 base pairs, consistent with other spectroscopic data, but not with another crystal structure reported [Pjura et al. (1987) J. Mol. Biol., 197, 257-271]. The two independent e6G-C base pairs in the DNA duplex adopt different base pairing schemes. The e6G4-C21 base pair has a configuration similar to a normal Watson-Crick base pair, except with bifurcated hydrogen bonds between e6G4 and C21, and the ethyl group is in the proximal orientation. In contrast, the e6G16-C9 base pair adopts a wobble configuration and the ethyl group is in the distal orientation.(ABSTRACT TRUNCATED AT 250 WORDS)

  • Organizational Affiliation

    Department of Physiology and Biophysics, University of Illinois, Urbana 61801.


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Entity ID: 1
MoleculeChains LengthOrganismImage
A, B
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HT1

Download Ideal Coordinates CCD File 
C27 H28 N6 O
Experimental Data & Validation

Experimental Data

  • Resolution: 2.25 Å
  • R-Value Observed: 0.168 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 25.686α = 90
b = 41.065β = 90
c = 66.416γ = 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: 1994-01-15
    Type: Initial release
  • Version 1.1: 2008-05-23
    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, Derived calculations