Download MendeleyPre-splicing conformation and stepwise circularization of a group I intron in Azoarcus pre-tRNA.
Hong, Y., Liu, J., Zhang, X., Liu, J., Li, S., Zhang, K.(2026) Nat Commun 17
- PubMed: 41862486 Search on PubMed
- DOI: https://doi.org/10.1038/s41467-026-70747-y
- Primary Citation Related Structures:
9V7N, 9V7O, 9V7P, 9V7Q, 9X6B - PubMed Abstract:
Group I introns are catalytic RNAs capable of self-splicing, yet structural insights into full-length precursor RNAs and post-splicing circularization have been limited. Here, we present cryo-EM structures of the Azoarcus pre-tRNA Ile system across key catalytic stages, including the full-length precursor in Pre-1S conformations, the linear intron, and the circular introns, at 2.8-3.3 Å resolution. These structures reveal a preformed P1 helix, register shifts during splicing, and a conformational flip of G37 that stabilizes the circularization site. Biochemical analyses confirm a two-step circularization mechanism, generating a secondary circular product via an alternative ligation site. Together, our results provide an atomic-level view of a group I intron system through splicing and circularization. This work uncovers structural principles governing RNA conformational dynamics, catalysis, and circular RNA formation, with broad implications for ribozyme engineering.
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, The RNA Institute, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
Organizational Affiliation:
