National Academy of Sciences, Proceedings of the National Academy of Sciences, 9(112), p. 2729-2733
DNA can adopt diverse structural conformations including duplexes, triplexes, and quadruplexes. Four-stranded structures known as G-quadruplexes have been implicated in cellular processes and found potential applications in therapeutics and nanotechnology. G-quadruplex structures are highly polymorphic, but so far, only right-handed helical forms have been observed. Here we present the NMR solution and X-ray crystal structures of an unprecedented left-handed DNA G-quadruplex, containing structural features that can be exploited as unique recognition elements.