Abstract
Wobble GU pairs (or G•U) occur frequently within double-stranded RNA helices interspersed between standard G=C and A-U Watson–Crick pairs. Another type of G•U pair interacting via their Watson–Crick edges has been observed in the A site of ribosome structures between a modified U34 in the tRNA anticodon triplet and G + 3 in the mRNA. In such pairs, the electronic structure of the U is changed with a negative charge on N3(U), resulting in two H-bonds between N1(G)…O4(U) and N2(G)…N3(U). Here, we report that such pairs occur in other highly conserved positions in ribosomal RNAs of bacteria in the absence of U modification. An anioniccisWatson–Crick G•G pair is also observed and well conserved in the small subunit. These pairs are observed in tightly folded regions.
Funder
LABEX
French National Research Agency
National Science Foundation Center for Genetically Encoded Materials
National Institute of General Medical Sciences of the National Institutes of Health
National Institutes of Health
Publisher
Cold Spring Harbor Laboratory