5LJ3

Structure of the core of the yeast spliceosome immediately after branching

Summary for 5LJ3

• Entry DOI: 10.2210/pdb5lj3/pdb
• EMDB information: 4055
• Descriptor: U5 snRNA (small nuclear RNA), ISY1, CWC22, ... (34 entities in total)
• Functional Keywords: spliceosome, snrnp, pre-mrna splicing, trans-esterification, lariat intermediate, complex c, splicing
• Biological source: Saccharomyces cerevisiae; More
• Total number of polymer chains: 38
• Total formula weight: 1755830.27

Authors

Galej, W.P.,Wilkinson, M.F.,Fica, S.M.,Oubridge, C.,Newman, A.J.,Nagai, K. (deposition date: 2016-07-17, release date: 2016-08-03, Last modification date: 2024-10-23)

Primary citation

Galej, W.P.,Wilkinson, M.E.,Fica, S.M.,Oubridge, C.,Newman, A.J.,Nagai, K.
Cryo-EM structure of the spliceosome immediately after branching.
Nature, 537:197-201, 2016

PubMed Abstract: Precursor mRNA (pre-mRNA) splicing proceeds by two consecutive transesterification reactions via a lariat-intron intermediate. Here we present the 3.8 Å cryo-electron microscopy structure of the spliceosome immediately after lariat formation. The 5'-splice site is cleaved but remains close to the catalytic Mg site in the U2/U6 small nuclear RNA (snRNA) triplex, and the 5'-phosphate of the intron nucleotide G(+1) is linked to the branch adenosine 2'OH. The 5'-exon is held between the Prp8 amino-terminal and linker domains, and base-pairs with U5 snRNA loop 1. Non-Watson-Crick interactions between the branch helix and 5'-splice site dock the branch adenosine into the active site, while intron nucleotides +3 to +6 base-pair with the U6 snRNA ACAGAGA sequence. Isy1 and the step-one factors Yju2 and Cwc25 stabilize docking of the branch helix. The intron downstream of the branch site emerges between the Prp8 reverse transcriptase and linker domains and extends towards the Prp16 helicase, suggesting a plausible mechanism of remodelling before exon ligation.

PubMed: 27459055
DOI: 10.1038/nature19316

Experimental method

ELECTRON MICROSCOPY (3.8 Å)