The exception that confirms the rule: a higher-order telomeric G-quadruplex structure more stable in sodium than in potassium.

ABSTRACT: DNA and RNA guanine-quadruplexes (G4s) are stabilized by several cations, in particular by potassium and sodium ions. Generally, potassium stabilizes guanine-quartet assemblies to a larger extent than sodium; in this article we report about a higher-order G4 structure more stable in sodium than in potassium. Repeats of the DNA GGGTTA telomeric motif fold into contiguous G4 units. Using three independent approaches (thermal denaturation experiments, isothermal molecular-beacon and protein-binding assays), we show that the (GGGTTA)7GGG sequence, folding into two contiguous G4 units, exhibits an unusual feature among G4 motifs: despite a lower thermal stability, its sodium conformation is more stable than its potassium counterpart at physiological temperature. Using differential scanning calo

SUBMITTER: Saintome C 

PROVIDER: S-EPMC4824101 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature