6EXN

Post-catalytic P complex spliceosome with 3' splice site docked

Summary for 6EXN

• Entry DOI: 10.2210/pdb6exn/pdb
• Related: 5MQ0 5MQF 5WSG 5XJC
• EMDB information: 3979
• Descriptor: U2 snRNA, Pre-mRNA-splicing factor PRP46, Pre-mRNA-processing protein 45, ... (40 entities in total)
• Functional Keywords: spliceosome, p-complex, exon ligation, splicing
• Biological source: Saccharomyces cerevisiae S288c; More
• Total number of polymer chains: 46
• Total formula weight: 2244126.52

Authors

Wilkinson, M.E.,Fica, S.M.,Galej, W.P.,Norman, C.M.,Newman, A.J.,Nagai, K. (deposition date: 2017-11-08, release date: 2018-01-17, Last modification date: 2020-10-07)

Primary citation

Wilkinson, M.E.,Fica, S.M.,Galej, W.P.,Norman, C.M.,Newman, A.J.,Nagai, K.
Postcatalytic spliceosome structure reveals mechanism of 3'-splice site selection.
Science, 358:1283-1288, 2017

PubMed Abstract: Introns are removed from eukaryotic messenger RNA precursors by the spliceosome in two transesterification reactions-branching and exon ligation. The mechanism of 3'-splice site recognition during exon ligation has remained unclear. Here we present the 3.7-angstrom cryo-electron microscopy structure of the yeast P-complex spliceosome immediately after exon ligation. The 3'-splice site AG dinucleotide is recognized through non-Watson-Crick pairing with the 5' splice site and the branch-point adenosine. After the branching reaction, protein factors work together to remodel the spliceosome and stabilize a conformation competent for 3'-splice site docking, thereby promoting exon ligation. The structure accounts for the strict conservation of the GU and AG dinucleotides at the 5' and 3' ends of introns and provides insight into the catalytic mechanism of exon ligation.

PubMed: 29146871
DOI: 10.1126/science.aar3729

Experimental method

ELECTRON MICROSCOPY (3.7 Å)