1IKK

Intrinsic Bending and Deformability at the T-A step of CCTTTAAAGG: A Comparative Analysis of T-A and A-T steps within A-tracts


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.177 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Intrinsic bending and deformability at the T-A step of CCTTTAAAGG: a comparative analysis of T-A and A-T steps within A-tracts.

Mack, D.R.Chiu, T.K.Dickerson, R.E.

(2001) J.Mol.Biol. 312: 1037-1049

  • DOI: 10.1006/jmbi.2001.4994

  • PubMed Abstract: 
  • Introduction of a T-A or pyrimidine-purine step into a straight and rigid A-tract can cause a positive roll deformation that kinks the DNA helix at that step. In CCTTTAAAGG, the central T-A step has an 8.6 degrees bend toward the major groove. We rep ...

    Introduction of a T-A or pyrimidine-purine step into a straight and rigid A-tract can cause a positive roll deformation that kinks the DNA helix at that step. In CCTTTAAAGG, the central T-A step has an 8.6 degrees bend toward the major groove. We report the structural analysis of CCTTTAAAGG and a comparison with 25 other representative crystal structures from the NDB containing at least four consecutive A or T bases. On average, more local bending occurs at the disruptive T-A step (8.21 degrees ) than at an A-T step (5.71 degrees ). In addition, A-tracts containing an A-T step are more bent than are pure A-tracts, and hence A-A and A-T steps are not equivalent. All T-A steps examined exhibit positive roll, bending towards the major groove, while A-T steps display negative roll and bend slightly towards the minor groove. This illustrates how inherent negative and positive roll are, respectively, at A-T and T-A steps within A-tracts. T-A steps are more deformable, showing larger and more variable deformations of minor groove width, rise, cup, twist, and buckle. Standard deviations of twist, rise, and cup for T-A steps are 6.66 degrees, 0.55 A, and 15.90 degrees, versus 2.28 degrees, 0.21 A, and 2.99 degrees for A-T steps. Packing constraints determine which local values of these helical parameters an individual T-A step will adopt. For instance, with CCTTTAAAGG and three isomorphous structures, CGATTAATCG, CGATATATCG, and CGATCGATCG, crystal packing forces lead to a series of correlated changes: widened minor groove, large slide, low twist, and large rise. The difference in helical parameters between A-T steps lying within A-tracts, versus A-T steps within alternating AT sequences, demonstrates the importance of neighboring steps on the conformation of a given dinucleotide step.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsLengthOrganism
5'-D(*CP*CP*TP*TP*TP*AP*AP*AP*GP*G)-3'A,B10N/A
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MG
Query on MG

Download SDF File 
Download CCD File 
A, B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.177 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 35.558α = 90.00
b = 38.737β = 90.00
c = 32.508γ = 90.00
Software Package:
Software NamePurpose
CNSphasing
CNSrefinement
SHELXL-97refinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-10-05
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance