Click chemistry for the identification of G-quadruplex structures: discovery of a DNA-RNA G-quadruplex.

A trap that closes with a "click": The copper-catalyzed azide-alkyne cycloaddition can occur in different G-quadruplex structures (see scheme). The species trapped by the click reaction can then be separated and analyzed. By using this approach, a DNA-RNA hybrid-type G-quadruplex structure formed by human telomeric DNA and RNA sequences was detected.