Figure 2.

Assignment of imino proton resonances. (A) The imino region of 1D ¹H-NMR spectrum and assignment of guanine residues in G-quartets. (B) 1D ¹⁵N filtered HSQC spectra of samples containing partially (6%) ¹⁵N residue-specifically labelled oligonucleotides. Spectra were recorded at 800 MHz (1D ¹H-NMR spectrum) and 600 MHz (1D ¹⁵N filtered HSQC spectra) at 25°C in 10% ²H₂O, 50 mM KCl, 10 mM phosphate buffer with pH 6.8. Oligonucleotide concentrations were between 1.5 and 2.7 mM.