Solution structures of multiple G-quadruplex complexes induced by a platinum(II)-based tripod reveal dynamic binding

Nat Commun. 2018 Aug 29;9(1):3496. doi: 10.1038/s41467-018-05810-4.

Abstract

DNA G-quadruplexes are not only attractive drug targets for cancer therapeutics, but also have important applications in supramolecular assembly. Here, we report a platinum(II)-based tripod (Pt-tripod) specifically binds the biological relevant hybrid-1 human telomeric G-quadruplex (Tel26), and strongly inhibits telomerase activity. Further investigations illustrate Pt-tripod induces the formation of monomeric and multimeric Pt-tripod‒Tel26 complex structures in solution. We solve the 1:1 and the unique dimeric 4:2 Pt-tripod-Tel26 complex structures by NMR. The structures indicate preferential binding of Pt-tripod to the 5'-end of Tel26 at a low Pt-tripod/Tel26 ratio of 0-1.0. After adding more Pt-tripod, the Pt-tripod binds the 3'-end of Tel26, unexpectedly inducing a unique dimeric 4:2 structure interlocked by an A:A non-canonical pair at the 3'-end. Our structures provide a structural basis for understanding the dynamic binding of small molecules with G-quadruplex and DNA damage mechanisms, and insights into the recognition and assembly of higher-order G-quadruplexes.

Publication types

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

MeSH terms

  • DNA / chemistry
  • G-Quadruplexes*
  • Humans
  • Organoplatinum Compounds / chemistry*
  • Platinum / chemistry*
  • Solutions / chemistry*
  • Telomerase
  • Telomere / chemistry

Substances

  • Organoplatinum Compounds
  • Solutions
  • Platinum
  • DNA
  • Telomerase