1A6H

DNA QUADRUPLEX CONTAINING GCGC TETRAD, NMR, 4 STRUCTURES


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 
  • Conformers Submitted: 
  • Selection Criteria: ALL CONFORMERS PRESENTED 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Solution structure of a DNA quadruplex containing the fragile X syndrome triplet repeat.

Kettani, A.Kumar, R.A.Patel, D.J.

(1995) J.Mol.Biol. 254: 638-656


  • PubMed Abstract: 
  • Both X-ray and NMR structural studies have defined the polymorphic nature of G-quadruplexes generated through mutual stacking of G.G.G.G tetrads by guanine rich telomeric sequences. Recently, the fragile X syndrome d(C-G-G)n triplet nucleotide repeat ...

    Both X-ray and NMR structural studies have defined the polymorphic nature of G-quadruplexes generated through mutual stacking of G.G.G.G tetrads by guanine rich telomeric sequences. Recently, the fragile X syndrome d(C-G-G)n triplet nucleotide repeat has been shown to form a stable quadruplex of undefined structure in monovalent cation solution. We have undertaken a structural characterization of the d(G-C-G-G-T3-G-C-G-G) undecanucleotide to elucidate the structural alignments associated with quadruplex formation by this oligomer which contains sequence elements associated with the fragile X syndrome triplet repeat. d(G-C-G-G-T3-G-C-G-G) in Na+ cation solution forms a quadruplex through dimerization of two symmetry related hairpins with the lateral connecting T3 loops positioned at opposite ends of the quadruplex. This novel NMR-molecular dynamics based solution structure contains internal G.C.G.C tetrads sandwiched between terminal G.G.G.G tetrads. Watson-Crick G.C base-pairs within individual hairpins dimerize through their major groove edges using bifurcated hydrogen bonds to form internal G(anti).C(anti).G(anti).C(anti) tetrads. Adjacent strands are anti-parallel to each other around the symmetric G-quadruplex which contains two distinct narrow and two symmetric wide grooves. By contrast, the terminal G-tetrads adopt G(syn).G(anti).G(syn).G(anti) alignments. The structure of the d(G-C-G-G-T3-G-C-G-G) quadruplex with its multi-layer arrangement of G.G.G.G and G.C.G.C tetrads greatly expands on our current knowledge of quadruplex folding topologies. Our results establish the pairing alignments that can be potentially utilized by the fragile X syndrome triplet repeat to form quadruplex structures through dimerization of hairpin stems. The formation of novel G.C.G.C tetrads through dimerization of Watson-Crick G.C base-pairs is directly relevant to the potential pairing alignments of helical stems in genetic recombination.


    Organizational Affiliation

    Cellular Biochemistry & Biophysics Program Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsLengthOrganism
DNA (5'-D(GP*CP*GP*GP*TP*TP*TP*GP*CP*GP*G)-3')A,B11N/A
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 
  • Conformers Submitted: 
  • Selection Criteria: ALL CONFORMERS PRESENTED 
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-06-17
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance