High-Throughput Synchrotron Radiation Circular Dichroism (HT-SRCD) for the screening of G-quadruplex ligands

G-quadruplexes (G4) are stable DNA/RNA structures formed by stacking guanine tetrads, supported by Hoogsteen hydrogen bonds and metal cations like K+ and Na+ . Found in proto-oncogenes, telomeres, and various organisms, G4s are crucial in gene expression. Research aims at finding specific ligands, including peptides, for therapeutic use. CD spectroscopy and HT-SRCD at Diamond Light Source was used to study G4 topologies and ligand binding. The stability and binding of three G4-forming strands were examined in 10 mM TRIS HCl buffer, pH 7.4, in the presence of either sodium or potassium ions.