Propeller-type parallel-stranded G-quadruplexes in the human c-myc promoter

J Am Chem Soc. 2004 Jul 21;126(28):8710-6. doi: 10.1021/ja048805k.


The nuclease-hypersensitivity element III1 in the c-myc promoter is a good anticancer target since it largely controls transcriptional activation of the important c-myc oncogene. Recently, the guanine-rich strand of this element has been shown to form an equilibrium between G-quadruplex structures built from two different sets of G-stretches; two models of intramolecular fold-back antiparallel-stranded G-quadruplexes, called "basket" and "chair" forms, were proposed. Here, we show by NMR that two sequences containing these two sets of G-stretches form intramolecular propeller-type parallel-stranded G-quadruplexes in K(+)-containing solution. The two structures involve a core of three stacked G-tetrads formed by four parallel G-stretches with all anti guanines and three double-chain-reversal loops bridging three G-tetrad layers. The central loop contains two or six residues, while the two other loops contain only one residue.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • DNA / chemistry*
  • Genes, myc / genetics*
  • Guanine / chemistry
  • Humans
  • Models, Genetic
  • Nucleic Acid Conformation*
  • Promoter Regions, Genetic / genetics*
  • Transcription, Genetic / genetics


  • Guanine
  • DNA