Download MendeleyVisualizing Group II Intron Catalysis through the Stages of Splicing.
Marcia, M., Pyle, A.M.(2012) Cell 151: 497-507
- PubMed: 23101623
- DOI: https://doi.org/10.1016/j.cell.2012.09.033
- Primary Citation of Related Structures:
4E8K, 4E8M, 4E8N, 4E8P, 4E8Q, 4E8R, 4E8T, 4E8V, 4FAQ, 4FAR, 4FAU, 4FAW, 4FAX, 4FB0 - PubMed Abstract:
Group II introns are self-splicing ribozymes that share a reaction mechanism and a common ancestor with the eukaryotic spliceosome, thereby providing a model system for understanding the chemistry of pre-mRNA splicing. Here we report 14 crystal structures of a group II intron at different stages of catalysis. We provide a detailed mechanism for the first step of splicing, we describe a reversible conformational change between the first and the second steps of splicing, and we present the ligand-free intron structure after splicing in an active state that corresponds to the retrotransposable form of the intron. During each reaction, the reactants are aligned and activated by a heteronuclear four-metal-ion center that contains a metal cluster and obligate monovalent cations, and they adopt a structural arrangement similar to that of protein endonucleases. Based on our data, we propose a model for the splicing cycle and show that it is applicable to the eukaryotic spliceosome.
Organizational Affiliation:
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA.
