Discriminating the conformation of G4 DNA by SANS.

Guanine-­rich DNA sequences are prone to fold into stable helical four­-stranded structures called G­quadruplexes (G4). These systems have drawn the attention of a number of scientists in both basic and applied research fields, including structural biophysics, cancer biology, novel therapeutics through to nanotechnology. And most importantly, G4s have been proposed as selective and effective therapeutic anticancer targets. However, the intrinsic polymorphism of G4s makes very challenging the prediction of the architectural folds encoded in guanine-rich DNA sequences. Up to now circular dichroism and NMR techniques have been extensively used to investigate the topology of G4 structures. Here we propose to investigate three G4s, selected on the basis of their conformational properties, to develop proof of concept for methodology for characterizing G4 architecture from SANS signature alone.