Figure 3.

NMR evidence for the formation of the kissing complex of H3–18. (A) A comparison between the ¹⁵N-¹⁴N filtered-NOESY (Left) and the usual unfiltered water NOESY (Right). Both were done at 10°C (mixing time 300 ms, 100 mM NaCl, pH 6.5). The C13, C14, C15, and C17 cross peaks in the unfiltered water NOESY are between the two C amino protons and the G imino protons in the G⋅C base pairs for the stem. The C10 cross peaks are from the intermolecular G11⋅C10 base pair. Only the G11⋅C10 cross peaks are seen in the left spectrum. (B) A comparison between the 2D ¹³C-¹²C HMQC-NOESY-HMQC (Left) and the regular D₂O NOESY (Right) in 100 mM NaCl, pH 6.5. Only cross peaks with black boxes in the right spectrum appear in the left spectrum showing the intermolecular NOEs; this indicates intermolecular interactions between A9H2 and C13 ribose protons.