All oligoribonucleotides: (AGG)2A, (AGG)4A, G(CGG)2C, G(CGG)4C, p(UGG)2U and p(UGG)4U were chemically synthesized on the Applied Biosystems DNA/RNA synthesizer using β-cyanoethyl phosphoramidite chemistry on solid support (36–38 ). The samples preparation procedure can be found in the Supplementary Data.
Our earlier experience with molecules composed of AGG, CGG and UGG repeats have shown that occasionally their spectroscopic features can be improved adding 5′-phosphate group. The role of 5′-phosphate has been discussed several times in the context of the G-quadruplex structures (39 (link),40 (link)). In this study, this type of modification was used only for UGG repeats, because it improved the quality of the 1H NMR spectra.
Our earlier experience with molecules composed of AGG, CGG and UGG repeats have shown that occasionally their spectroscopic features can be improved adding 5′-phosphate group. The role of 5′-phosphate has been discussed several times in the context of the G-quadruplex structures (39 (link),40 (link)). In this study, this type of modification was used only for UGG repeats, because it improved the quality of the 1H NMR spectra.
