Journal: Cell / Year: 2017 Title: An Atomic Structure of the Human Spliceosome. Authors: Xiaofeng Zhang / Chuangye Yan / Jing Hang / Lorenzo I Finci / Jianlin Lei / Yigong Shi / Abstract: Mechanistic understanding of pre-mRNA splicing requires detailed structural information on various states of the spliceosome. Here we report the cryo electron microscopy (cryo-EM) structure of the ...Mechanistic understanding of pre-mRNA splicing requires detailed structural information on various states of the spliceosome. Here we report the cryo electron microscopy (cryo-EM) structure of the human spliceosome just before exon ligation (the C complex) at an average resolution of 3.76 Å. The splicing factor Prp17 stabilizes the active site conformation. The step II factor Slu7 adopts an extended conformation, binds Prp8 and Cwc22, and is poised for selection of the 3'-splice site. Remarkably, the intron lariat traverses through a positively charged central channel of RBM22; this unusual organization suggests mechanisms of intron recruitment, confinement, and release. The protein PRKRIP1 forms a 100-Å α helix linking the distant U2 snRNP to the catalytic center. A 35-residue fragment of the ATPase/helicase Prp22 latches onto Prp8, and the quaternary exon junction complex (EJC) recognizes upstream 5'-exon sequences and associates with Cwc22 and the GTPase Snu114. These structural features reveal important mechanistic insights into exon ligation.
History
Deposition
Apr 30, 2017
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Header (metadata) release
Jun 28, 2017
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Map release
Jul 5, 2017
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Update
Oct 14, 2020
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Current status
Oct 14, 2020
Processing site: PDBj / Status: Released
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Structure visualization
Movie
Surface view with section colored by density value
Chromatic aberration corrector: -10 / Energy filter - Name: GIF Quantum LS / Energy filter - Lower energy threshold: 0 eV / Energy filter - Upper energy threshold: 10 eV
Image recording
Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Detector mode: SUPER-RESOLUTION / Digitization - Frames/image: 2-32 / Number grids imaged: 5 / Number real images: 7308 / Average exposure time: 0.25 sec. / Average electron dose: 50.0 e/Å2
Electron beam
Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
Electron optics
Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm
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