Structure of a two-G-tetrad intramolecular G-quadruplex formed by a variant human telomeric sequence in K+ solution: insights into the interconversion of human telomeric G-quadruplex structures

Nucleic Acids Res. 2010 Jan;38(3):1009-21. doi: 10.1093/nar/gkp1029. Epub 2009 Nov 27.


Human telomeric DNA G-quadruplex has been considered as an attractive target for cancer therapeutic intervention. The telomeric sequence shows intrinsic structure polymorphism. Here we report a novel intramolecular G-quadruplex structure formed by a variant human telomeric sequence in K(+) solution. This sequence forms a basket-type intramolecular G-quadruplex with only two G-tetrads but multiple-layer capping structures formed by loop residues. While it is shown that this structure can only be detected in the specifically truncated telomeric sequences without any 5'-flanking residues, our results suggest that this two-G-tetrad conformation is likely to be an intermediate form of the interconversion of different telomeric G-quadruplex conformations.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • DNA / chemistry*
  • G-Quadruplexes*
  • Humans
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular
  • Potassium / chemistry*
  • Protons
  • Telomere / chemistry*


  • Protons
  • DNA
  • Potassium