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Cell. 2012 Oct 26;151(3):497-507. doi: 10.1016/j.cell.2012.09.033.

Visualizing group II intron catalysis through the stages of splicing.

Author information

1
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA.

Erratum in

  • Cell. 2012 Dec 7;151(6):1386.

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.

PMID:
23101623
PMCID:
PMC3628766
DOI:
10.1016/j.cell.2012.09.033
[Indexed for MEDLINE]
Free PMC Article

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