EMD-32318

Single-particle
3.9 Å
EMD-32318 Deposition: 29/11/2021
Map released: 22/06/2022
Last modified: 17/08/2022
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-32318

The cryo-EM map of PRP22 region of human pre-C*-I complex

EMD-32318

Single-particle
3.9 Å
EMD-32318 Deposition: 29/11/2021
Map released: 22/06/2022
Last modified: 17/08/2022
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Homo sapiens
Sample: Human pre-C*-I complex

Deposition Authors: Zhan X , Lu Y, Shi Y
Mechanism of exon ligation by human spliceosome.
Zhan X , Lu Y, Zhang X, Yan C, Shi Y
(2022) Mol Cell , 82 , 2769 - 2778.e4
PUBMED: 35705093
DOI: doi:10.1016/j.molcel.2022.05.021
ISSN: 1097-2765
ASTM: MOCEFL
Abstract:
Pre-mRNA splicing involves two sequential reactions: branching and exon ligation. The C complex after branching undergoes remodeling to become the C complex, which executes exon ligation. Here, we report cryo-EM structures of two intermediate human spliceosomal complexes, pre-C-I and pre-C-II, both at 3.6 Å. In both structures, the 3' splice site is already docked into the active site, the ensuing 3' exon sequences are anchored on PRP8, and the step II factor FAM192A contacts the duplex between U2 snRNA and the branch site. In the transition of pre-C-I to pre-C-II, the step II factors Cactin, FAM32A, PRKRIP1, and SLU7 are recruited. Notably, the RNA helicase PRP22 is positioned quite differently in the pre-C-I, pre-C-II, and C complexes, suggesting a role in 3' exon binding and proofreading. Together with information on human C and C complexes, our studies recapitulate a molecular choreography of the C-to-C transition, revealing mechanistic insights into exon ligation.