2meq

Publication Abstract from PubMed

Helix 69 (H69) is a 19-nt stem-loop region from the large subunit ribosomal RNA. Three pseudouridine (Psi) modifications clustered in H69 are conserved across phylogeny and known to affect ribosome function. To explore the effects of Psi on the conformations of Escherichia coli H69 in solution, nuclear magnetic resonance spectroscopy was used to reveal the structural differences between H69 with (PsiPsiPsi) and without (UUU) Psi modifications. Comparison of the two structures shows that H69 PsiPsiPsi has the following unique features: (i) the loop region is closed by a Watson-Crick base pair between Psi1911 and A1919, which is potentially reinforced by interactions involving Psi1911N1H and (ii) Psi modifications at loop residues 1915 and 1917 promote base stacking from Psi1915 to A1918. In contrast, the H69 UUU loop region, which lacks Psi modifications, is less organized. Structure modulation by Psi leads to alteration in conformational behavior of the 5' half of the H69 loop region, observed as broadening of C1914 non-exchangeable base proton resonances in the H69 PsiPsiPsi nuclear magnetic resonance spectra, and plays an important biological role in establishing the ribosomal intersubunit bridge B2a and mediating translational fidelity.

Structure modulation of helix 69 from Escherichia coli 23S ribosomal RNA by pseudouridylations.,Jiang J, Aduri R, Chow CS, Santalucia J Jr Nucleic Acids Res. 2013 Dec 26. PMID:24371282^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.