2KF7

Structure of a two-G-tetrad basket-type intramolecular G-quadruplex formed by human telomeric repeats in K+ solution (with G7-to-BRG substitution)


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 10 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum 

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Literature

Structure of the human telomere in K+ solution: a stable basket-type G-quadruplex with only two G-tetrad layers

Lim, K.W.Amrane, S.Bouaziz, S.Xu, W.Mu, Y.Patel, D.J.Luu, K.N.Phan, A.T.

(2009) J Am Chem Soc 131: 4301-4309

  • DOI: https://doi.org/10.1021/ja807503g
  • Primary Citation of Related Structures:  
    2KF7, 2KF8

  • PubMed Abstract: 

    Previously, it has been reported that human telomeric DNA sequences could adopt in different experimental conditions four different intramolecular G-quadruplexes each involving three G-tetrad layers, namely, Na(+) solution antiparallel-stranded basket form, K(+) crystal parallel-stranded propeller form, K(+) solution (3 + 1) Form 1, and K(+) solution (3 + 1) Form 2. Here we present a new intramolecular G-quadruplex adopted by a four-repeat human telomeric sequence in K(+) solution (Form 3). This structure is a basket-type G-quadruplex with only two G-tetrad layers: loops are successively edgewise, diagonal, and edgewise; glycosidic conformations of guanines are syn x syn x anti x anti around each tetrad. Each strand of the core has both a parallel and an antiparallel adjacent strands; there are one narrow, one wide, and two medium grooves. Despite the presence of only two G-tetrads in the core, this structure is more stable than the three-G-tetrad intramolecular G-quadruplexes previously observed for human telomeric sequences in K(+) solution. Detailed structural elucidation of Form 3 revealed extensive base pairing and stacking in the loops capping both ends of the G-tetrad core, which might explain the high stability of the structure. This novel structure highlights the conformational heterogeneity of human telomeric DNA. It establishes a new folding principle for G-quadruplexes and suggests new loop sequences and structures for targeting in human telomeric DNA.


  • Organizational Affiliation

    School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore.


Macromolecules

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Entity ID: 1
MoleculeChains LengthOrganismImage
HUMAN TELOMERE DNA22N/A
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 10 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-03-24
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance