Formation and Behavior of Guanosine-5'-Monophosphate assemblies at low pH: temperature and cation effects
Abstrakt
Self-assembly of mononucleotides and their oligo- and polymeric forms (nucleic acids) into higher-ordered structures is ubiquitous in living systems. However, Guanosine 5'-monophosphate (5'-GMP) and its derivatives are special among other nucleotides, because at higher concentrations they self-associate into unique structures - first guanine quartets1, which then stack and form G-quadruplexes (G4).
G4 are stabilized by a combination of several contributions: Hoogsteen base pairing, base stacking, cation coordination, hydrophobic interaction, and H-bonds between phosphates and hydroxyl groups of neighboring nucleotides. 5'-GMP self-association is pronounced at low pH (~5) resulting in a highly viscous gel. Under these conditions, the planarity of the stacked G-quartets is broken, and G4 forms a continuous helix2.