Figure 3.

(A) ¹H-1D NMR spectra of the in-trans construct Zsw⁴⁸+Zsw¹⁵ and Zsw⁷⁷ before and after addition of 2 eq. ZMP in presence of 10 mM Mg²⁺. (B) ¹⁵N-edited and conventional ¹H-1D NMR spectra of ¹⁵N-Zsw⁴⁸+¹⁴N-Zsw¹⁵ and conventional ¹H-1D of Zsw¹⁵ in the presence of 10 mM Mg²⁺. Peaks that arise only in the conventional spectrum marked with arrows. Samples contained 100 μM RNA. Stacked and enlarged representations of those spectra are shown in Supplementary Figure S2. (C) Schematic representation of the labelling scheme of ¹⁵N-Zsw⁴⁸+¹⁴N-Zsw¹⁵. Colors of base-pairs according to arrow colors in (B). (D) 12 % native PAGE of Zsw⁴⁸ in the presence of 1eq Zsw¹⁵, 10 mM Mg²⁺ and 1 eq. ZMP. Pockets were loaded with 200 nmol Zsw⁴⁸ and additions as indicated. The gel is displayed enlarged in Supplementary Figure S3 (E) Top: ¹⁵N-SOFAST-HMQC spectrum (37) of Zsw⁴⁸ before (cyan) and after (black) addition of Zsw¹⁵ in the presence of 10 mM Mg²⁺. Spectra were recorded at 800 MHz at room temperature with 2048 × 128 points and 8 scans. Bottom: ¹⁵N-edited ¹H,¹H-NOESY of Zsw⁴⁸+Zsw¹⁵ with the cross peaks that arise from addition of Zsw¹⁵ marked blue. Spectra were recorded at 800 MHz with 2048 × 432 points and 256 scans.