Guanosine Quadruplexes in Solution : A Small-Angle X-Ray Scattering Analysis of Temperature Effects on Self-Assembling of Deoxyguanosine Monophosphate

Abstract EN

We investigated quadruplex formation in aqueous solutions of 2′-deoxyriboguanosine 5′-monophosphate, d(pG), which takes place in the absence of the covalent axial backbone.

A series of in-solution small angle X-ray scattering experiments on d(pG) have been performed as a function of temperature in the absence of excess salt, at a concentration just above the critical one at which self-assembling occurs.

A global fit approach has been used to derive composition and size distribution of the scattering particles as a function of temperature.

The obtained results give thermodynamical justification for the observed phase-behavior, indicating that octamer formation is essential for quadruplex elongation.

Our investigation shows that d(pG) quadruplexes are very suitable to assess the potential of G-quadruplex formation and to study the self-assembling thermodynamics.