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Updated: Aug 2, 2025
Dual DNA Rulers to Study the Mechanism of Ribosome Translocation with Single-Nucleotide Resolution
Published on: July 8, 2019
Anionic G•U pairs in bacterial ribosomal rRNAs
Eric Westhof1, Zoe L Watson2,3, Craig L Zirbel4
1Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, F-67084 Strasbourg, France e.westhof@ibmc-cnrs.unistra.fr.
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 anionic cis Watson-Crick G•G pair is also observed and well conserved in the small subunit. These pairs are observed in tightly folded regions.
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