8XI2

Cryo-EM structure of the Chlamydomonas C* complex

Summary for 8XI2

• Entry DOI: 10.2210/pdb8xi2/pdb
• EMDB information: 38362
• Descriptor: MPN domain-containing protein, Sm protein F, Small nuclear ribonucleoprotein Sm D2, ... (34 entities in total)
• Functional Keywords: chlamydomonas spliceosome, c* complex, cdc5l, rna splicing, splicing
• Biological source: Chlamydomonas reinhardtii; More
• Total number of polymer chains: 34
• Total formula weight: 2006132.09

Authors

Lu, Y.,Zhan, X. (deposition date: 2023-12-19, release date: 2024-10-09, Last modification date: 2025-07-02)

Primary citation

Lu, Y.,Liang, K.,Zhan, X.
Structure of a step II catalytically activated spliceosome from Chlamydomonas reinhardtii.
Embo J., 44:975-990, 2025

PubMed Abstract: Pre-mRNA splicing, a fundamental step in eukaryotic gene expression, is executed by the spliceosomes. While there is extensive knowledge of the composition and structure of spliceosomes in yeasts and humans, the structural diversity of spliceosomes in non-canonical organisms remains unclear. Here, we present a cryo-EM structure of a step II catalytically activated spliceosome (C complex) derived from the unicellular green alga Chlamydomonas reinhardtii at 2.6 Å resolution. This Chlamydomonas C complex comprises 29 proteins and four RNA elements, creating a dynamic assembly that shares a similar overall architecture with yeast and human counterparts but also has unique features of its own. Distinctive structural characteristics include variations in protein compositions as well as some noteworthy RNA features. The splicing factor Prp17, with four fragments and a WD40 domain, is engaged in intricate interactions with multiple protein and RNA components. The structural elucidation of Chlamydomonas C complex provides insights into the molecular mechanism of RNA splicing in plants and understanding splicing evolution in eukaryotes.

PubMed: 39415054
DOI: 10.1038/s44318-024-00274-3

Experimental method

ELECTRON MICROSCOPY (2.6 Å)