5nrl | pdb_00005nrl
Structure of a pre-catalytic spliceosome.
Structural highlights
FunctionDIB1_YEAST Essential role in pre-mRNA splicing. Also essential for entry into mitosis (G2/M progression) as well as for chromosome segregation during mitosis. Publication Abstract from PubMedIntron removal requires assembly of the spliceosome on precursor mRNA (pre-mRNA) and extensive remodelling to form the spliceosome's catalytic centre. Here we report the cryo-electron microscopy structure of the yeast Saccharomyces cerevisiae pre-catalytic B complex spliceosome at near-atomic resolution. The mobile U2 small nuclear ribonucleoprotein particle (snRNP) associates with U4/U6.U5 tri-snRNP through the U2/U6 helix II and an interface between U4/U6 di-snRNP and the U2 snRNP SF3b-containing domain, which also transiently contacts the helicase Brr2. The 3' region of the U2 snRNP is flexibly attached to the SF3b-containing domain and protrudes over the concave surface of tri-snRNP, where the U1 snRNP may reside before its release from the pre-mRNA 5' splice site. The U6 ACAGAGA sequence forms a hairpin that weakly tethers the 5' splice site. The B complex proteins Prp38, Snu23 and Spp381 bind the Prp8 N-terminal domain and stabilize U6 ACAGAGA stem-pre-mRNA and Brr2-U4 small nuclear RNA interactions. These results provide important insights into the events leading to active site formation. Structure of a pre-catalytic spliceosome.,Plaschka C, Lin PC, Nagai K Nature. 2017 Jun 29;546(7660):617-621. doi: 10.1038/nature22799. Epub 2017 May, 22. PMID:28530653[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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