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Publication Abstract from PubMed

The spliceosome undergoes dramatic changes in a splicing cycle. Structures of B, B(act), C, C*, and intron lariat spliceosome complexes revealed mechanisms of 5'-splice site (ss) recognition, branching, and intron release, but lacked information on 3'-ss recognition, exon ligation, and exon release. Here we report a cryo-electron microscopy structure of the postcatalytic P complex at 3.3-angstrom resolution, revealing that the 3' ss is mainly recognized through non-Watson-Crick base pairing with the 5' ss and branch point. Furthermore, one or more unidentified proteins become stably associated with the P complex, securing the 3' exon and potentially regulating activity of the helicase Prp22. Prp22 binds nucleotides 15 to 21 in the 3' exon, enabling it to pull the intron-exon or ligated exons in a 3' to 5' direction to achieve 3'-ss proofreading or exon release, respectively.

Structure of the yeast spliceosomal postcatalytic P complex.,Liu S, Li X, Zhang L, Jiang J, Hill RC, Cui Y, Hansen KC, Zhou ZH, Zhao R Science. 2017 Dec 8;358(6368):1278-1283. doi: 10.1126/science.aar3462. Epub 2017 , Nov 16. PMID:29146870^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.