A novel equilibrium relating to the helix handedness in G-quadruplexes formed by heterochiral oligonucleotides with an inversion of polarity site

Abstract

Investigations of heterochiral oligodeoxynucleotides 5′-T_D1G_D2G_D3-3′-3′-G_L3G_L2T_L1-5′ (L33) and 3′-T_D1G_D2G_D3-5′-5′-G_L3G_L2T_L1-3′ (L55) forming quadruplex structures are reported. Data indicate the presence of enantiomeric left- and right-handed quadruplex helices. In the case of L55, NMR experiments point to an unusual equilibrium between them.