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

Abstract

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.

GENFIT: software for the analysis of small-angle X-ray and neutron scattering data of macromolecules in solution

“…SAS has also been used to monitor complex aggregation/fragmentation processes in solution (Mariani et al, 2009(Mariani et al, , 2010Gonnelli et al, 2013). In particular, the possibility of defining link functions and global parameters in the GENFIT data analysis process allowed several guanosine aggregate species formed by self-assembly in solution to be resolved in terms of concentration and composition.…”

Circular dichroism and UV-Vis absorption spectroscopic monitoring of production of chiral silver nanoparticles templated by guanosine 5′-monophosphate

“…18 Also the 2 0 -deoxyriboguanosine-5 0 -monophosphate (5 0 -dGMP) has been intensively studied in aqueous solutions; in the presence of sodium ions this nucleotide forms quadruplexes (four-stranded helical structures) resulting from the staking of planar quartets. 19 Guanosine 5 0 -monophosphate (5 0 -GMP) shows a great affinity for silver ions and self-assembles into a hierarchical structure under specific conditions. 20,21 The proposed basic unit is a planar dimer complex of 5 0 -GMP with silver ions which are coordinated with N7, O6 atoms and the phosphate group (Fig.…”

How soft are biological helices? A measure of axial and lateral force constants in folate quadruplexes by high-pressure X-ray diffraction

“…Quadruplex structures have been observed in guanosinerich single stranded sequences of DNA (as in telomeres and in other parts of the genome, especially in promoters (4,5)) and in guanosine and oligo-guanosine systems (for example, guanosine 5'-monophosphate, Gp, deoxyguanosine 5'-monophosphate, d(Gp), and short oligo-guanosines as dGpG, dGpGpG, and so on) (6). Guanosines and oligo-guanosines show a hierarchical self-assembling (3,7), which is plainly illustrated in Figure 1. In aqueous solution, the process starts in dilute conditions, with the formation of tetrameric disks made by four Hoogsteen hydrogen-bonded guanine residues.…”