4r0d

Crystal structure of a eukaryotic group II intron lariat

spinqualitylabelsall models 4r0d, resolution 3.68Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4r0d is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: IRI, MG, NA, SPM Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed The formation of branched lariat RNA is an evolutionarily conserved feature of splicing reactions for both group II and spliceosomal introns. The lariat is important for the fidelity of 5' splice-site selection and consists of a 2'-5' phosphodiester bond between a bulged adenosine and the 5' end of the intron. To gain insight into this ubiquitous intramolecular linkage, we determined the crystal structure of a eukaryotic group IIB intron in the lariat form at 3.7 A. This revealed that two tandem tetraloop-receptor interactions, eta-eta' and pi-pi', place domain VI in the core to position the lariat bond in the post-catalytic state. On the basis of structural and biochemical data, we propose that pi-pi' is a dynamic interaction that mediates the transition between the two steps of splicing, with eta-eta' serving an ancillary role. The structure also reveals a four-magnesium-ion cluster involved in both catalysis and positioning of the 5' end. Given the evolutionary relationship between group II and nuclear introns, it is likely that this active site configuration exists in the spliceosome as well. Crystal structure of a eukaryotic group II intron lariat.,Robart AR, Chan RT, Peters JK, Rajashankar KR, Toor N Nature. 2014 Sep 24. doi: 10.1038/nature13790. PMID:25252982 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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