Fig. 2.

Structural integrity of caged dGsw¹²¹ before and after laser irradiation. a Secondary structures of dGsw¹²¹ in presence and absence of ligand, before photolysis (PA–T) and after photolysis to form the antiterminator conformations P^AT(M) and P^AT(I). Aptamer domain imino protons detectable by NMR are highlighted in orange. Antiterminator imino protons detectable by NMR are highlighted in green. b Overlay of 1D NMR spectra of caged dGsw¹²¹ before (black) and after (green) laser irradiation in absence (left) and presence (right) of 2 eq. of ligand  and combinations of overlay of ¹H,¹⁵N -TROSY of dGsw¹²¹ in absence (−2′dG) or presence of 2 eq. ligand ( + 2′dG), and before and after ( + hν) laser irradiation. The spectra were recorded on 100 µM NMR samples with 6 eq. of Mg²⁺ at 800 MHz and 298 K. Characteristic imino proton signals to monitor the formation of P^AT are highlighted in green. Characteristic imino proton signals to monitor aptamer dissociation in the presence of ligand are highlighted in red