Coexistence of two distinct G-quadruplex conformations in the hTERT promoter

The NMR solution structures of two G-quadruplex conformations in potassium solution: a (3 + 1) and a parallel-stranded G-quadruplexes were explored to understand their coexistance in guanine-rich stretches of human telomerase, hTERT promoter. The findings from a combination of NMR and CD techniques, complemented with sequence modifications and variations of experimental condition provide better insight into the coexistence of the two G-quadruplex conformations in equilibrium and the way different structural elements adapt to favor a particular form.