Prevalence of H-bonding interactions among amines. (A) Percentage of non-, single-, and dual-donating amines among all A's, C's, and G's. The nine columns sum to 100%. The number of amines surveyed are provided above the plots, and the number belonging to each donor type are provided below its respective column. (B) Number and identity of acceptor pairs that are engaged with dual-donating amines. Hatched portions of columns represent the number of acceptor pairs that are part of the same residue, and the numbers above these columns indicate the fraction of pairs belonging to the same residue. When the acceptor is a backbone atom, canonical RNA and amino acid residues are denoted with “N” and “AA,” respectively. The top 10 acceptor pairs per nucleobase amine are provided. Select examples of these interactions are provided in Figure 5 and Supplemental Figure S2.
