9GCM

Structure of the U11 snRNP core

Summary for 9GCM

• Entry DOI: 10.2210/pdb9gcm/pdb
• EMDB information: 51234
• Descriptor: U11 snRNA, U11/U12 small nuclear ribonucleoprotein 25 kDa protein, U11/U12 small nuclear ribonucleoprotein 35 kDa protein, ... (4 entities in total)
• Functional Keywords: minor spliceosome, u11 snrnp, rna-protein complex, splicing
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 143102.81

Authors

Zhao, J.,Galej, W.P. (deposition date: 2024-08-02, release date: 2025-02-05, Last modification date: 2025-02-19)

Primary citation

Zhao, J.,Peter, D.,Brandina, I.,Liu, X.,Galej, W.P.
Structural basis of 5' splice site recognition by the minor spliceosome.
Mol.Cell, 85:652-, 2025

PubMed Abstract: The minor spliceosome catalyzes excision of U12-dependent introns from precursors of eukaryotic messenger RNAs (pre-mRNAs). This process is critical for many cellular functions, but the underlying molecular mechanisms remain elusive. Here, we report a cryoelectron microscopy (cryo-EM) reconstruction of the 13-subunit human U11 small nuclear ribonucleoprotein particle (snRNP) complex in apo and substrate-bound forms, revealing the architecture of the U11 small nuclear RNA (snRNA), five minor spliceosome-specific factors, and the mechanism of the U12-type 5' splice site (5'SS) recognition. SNRNP25 and SNRNP35 specifically recognize U11 snRNA, while PDCD7 bridges SNRNP25 and SNRNP48, located at the distal ends of the particle. SNRNP48 and ZMAT5 are positioned near the 5' end of U11 snRNA and stabilize binding of the incoming 5'SS. Recognition of the U12-type 5'SS is achieved through base-pairing to the 5' end of the U11 snRNA and unexpected, non-canonical base-triple interactions with the U11 snRNA stem-loop 3. Our structures provide mechanistic insights into U12-dependent intron recognition and the evolution of the splicing machinery.

PubMed: 39809272
DOI: 10.1016/j.molcel.2024.12.017

Experimental method

ELECTRON MICROSCOPY (3.1 Å)