Structural analysis of uridine modifications in solved RNA structures

Area of Science:

• RNA structural biology
• Chemical biology
• Biochemistry

Background:

• Uridine modifications are crucial for RNA stability, translation, and immune responses.
• Comprehensive structural analysis of these modifications in 3D RNA structures is limited.
• Six key uridine modifications (pseudouridine, 5-methyluridine, 3-methyluridine, O2'-methyluridine, 4-thiouridine, 5,6-dihydrouridine) were investigated.

Purpose of the Study:

• To systematically analyze the structural characteristics of six common uridine modifications in experimentally determined RNA 3D structures.
• To investigate the conformational preferences and structural impacts of these modifications.
• To provide insights into the functional implications of uridine modifications in RNA.

Main Methods:

• Utilized data from the Research Collaboratory for Structural Bioinformatics Protein Data Bank for RNA-containing structures.
• Performed systematic curation and identification of six uridine modifications (PSU, 5MU, UR3, OMU, 4SU, H2U).
• Conducted sugar pucker analysis and root-mean-square deviation (RMSD) analysis to compare modified and unmodified RNA structures.

Main Results:

• Identified a significant number of modified residues across various RNA types, predominantly in ribosomal and transfer RNAs.
• Observed modification-specific preferences for sugar pucker conformations (C3'-endo and C2'-endo).
• Found high structural similarity between modified and unmodified uridines (RMSD ≤ 1.0 Å), with notable exceptions in specific motifs, and identified differences in interactions.

Conclusions:

• Uridine modifications exhibit distinct conformational behaviors and localized structural impacts within RNA.
• These modifications, while generally maintaining overall RNA structure, can alter local interactions.
• The findings enhance our understanding of RNA modification roles and inform RNA-targeted therapeutics and structural biology research.