5gm6
Cryo-EM structure of the activated spliceosome (Bact complex) at 3.5 angstrom resolutionCryo-EM structure of the activated spliceosome (Bact complex) at 3.5 angstrom resolution
Structural highlights
FunctionSN114_YEAST Component of the U5 snRNP complex required for pre-mRNA splicing. Binds GTP. Publication Abstract from PubMedPre-messenger RNA (pre-mRNA) splicing is carried out by the spliceosome, which undergoes an intricate assembly and activation process. Here, we report an atomic structure of an activated spliceosome (known as the B(act) complex) from Saccharomyces cerevisiae, determined by cryo-electron microscopy at an average resolution of 3.52 angstroms. The final refined model contains U2 and U5 small nuclear ribonucleoprotein particles (snRNPs), U6 small nuclear RNA (snRNA), nineteen complex (NTC), NTC-related (NTR) protein, and a 71-nucleotide pre-mRNA molecule, which amount to 13,505 amino acids from 38 proteins and a combined molecular mass of about 1.6 megadaltons. The 5' exon is anchored by loop I of U5 snRNA, whereas the 5' splice site (5'SS) and the branch-point sequence (BPS) of the intron are specifically recognized by U6 and U2 snRNA, respectively. Except for coordination of the catalytic metal ions, the RNA elements at the catalytic cavity of Prp8 are mostly primed for catalysis. The catalytic latency is maintained by the SF3b complex, which encircles the BPS, and the splicing factors Cwc24 and Prp11, which shield the 5' exon-5'SS junction. This structure, together with those determined earlier, outlines a molecular framework for the pre-mRNA splicing reaction. Structure of a yeast activated spliceosome at 3.5 A resolution.,Yan C, Wan R, Bai R, Huang G, Shi Y Science. 2016 Aug 26;353(6302):904-11. doi: 10.1126/science.aag0291. Epub 2016, Jul 21. PMID:27445306[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
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