Effect of ribose versus 2 '-deoxyribose residue in guanosine 5 '-monophosphates on formation of G-quartets stabilized by potassium and sodium cations
Abstract
Raman spectroscopy was used to directly compare different abilities of monomeric ribo- and 2'- deoxyribo guanosine 5'-monophosphates to constitute G-quartets and their supramolecular selfassemblies stabilized by Na+ and K+ cations in pH-neutral or slightly basic aqueous solutions. Nucleotide concentration, stoichiometry and temperature was systematically varied to show that in the presence of Na+ cations, 5'-dGMP remains unordered under the conditions when 5'-rGMP already forms Na+-stabilized G-quartets and soluble ordered assemblies.
On the contrary, in the presence of K+ ions both 5'-GMPs readily form self-stacking G-quartets, although self-association of 5'-rGMP is still greater than that of 5'-dGMP. These results are supported by 1H and 31P NMR spectroscopy.
The cation-sensitive effect of ribose versus 2'-deoxyribose substitution on the formation of G-quartets and soluble aggregates from monomeric 5'-guanosine monophosphates under physiological pH could be essential for full understanding of different structural polymorphism of RNA and DNA quadruplexes.