d(TGnT) DNA sequences do not necessarily form tetramolecular G-quadruplexes

Contrasting with the common belief that d(TG(n)T) DNA sequences would form tetramolecular G-quadruplex assemblies, mass spectrometry reveals that these sequences tend to fold into G-quadruplex trimers, dimers, and eventually monomers as the G-tract length increases. The final structure also depends on the ionic strength.