Sequence variant (CTAGGG)n in the human telomere favors a G-quadruplex structure containing a G.C.G.C tetrad

Nucleic Acids Res. 2009 Oct;37(18):6239-48. doi: 10.1093/nar/gkp630. Epub 2009 Aug 19.


Short contiguous arrays of variant CTAGGG repeats in the human telomere are unstable in the male germline and somatic cells, suggesting formation of unusual structures by this repeat type. Here, we report on the structure of an intramolecular G-quadruplex formed by DNA sequences containing four human telomeric variant CTAGGG repeats in potassium solution. Our results reveal a new robust antiparallel G-quadruplex fold involving two G-tetrads sandwiched between a G.C base pair and a G.C.G.C tetrad, which could represent a new platform for drug design targeted to human telomeric DNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calorimetry
  • Circular Dichroism
  • Electrophoresis, Polyacrylamide Gel
  • G-Quadruplexes*
  • Genetic Variation
  • Humans
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular
  • Potassium / chemistry
  • Repetitive Sequences, Nucleic Acid
  • Spectrophotometry, Ultraviolet
  • Telomere / chemistry*
  • Thermodynamics


  • Potassium