Download MendeleyStructural basis of circularly permuted group II intron self-splicing.
Wang, L., Xie, J., Zhang, C., Zou, J., Huang, Z., Shang, S., Chen, X., Yang, Y., Liu, J., Dong, H., Huang, D., Su, Z.(2025) Nat Struct Mol Biol 32: 1091-1100
- PubMed: 39890981
- DOI: https://doi.org/10.1038/s41594-025-01484-x
- Primary Citation of Related Structures:
8XTP, 8XTQ, 8XTR, 8XTS, 9IS7 - PubMed Abstract:
Circularly permuted group II introns (CP introns) consist of rearranged structural domains separated by two tethered exons, generating branched introns and circular exons via back-splicing. Structural and mechanistic understanding of circular RNA (circRNA) generation by CP introns remains elusive. We resolve cryo-electron microscopy structures of a natural CP intron in different states during back-splicing at a resolution of 2.5-2.9 Å. Domain 6 (D6) undergoes a conformational change of 65° after branching, to facilitate 3'-exon recognition and circularization. Previously unseen tertiary interactions compact the catalytic triad and D6 for splicing without protein, whereas a metal ion, M 35 , is observed to stabilize the 5'-exon during splicing. While these unique features were not observed in canonical group II introns and spliceosomes, they are common in CP introns, as demonstrated by the cryo-EM structure of another CP intron discovered by comparative genomics analysis. Our results elucidate the mechanism of CP intron back-splicing dynamics, with potential applications in circRNA research and therapeutics.
- The State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital; The State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, National Center for Stomatology, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Organizational Affiliation:
