6AH0

The Cryo-EM Structure of the Precusor of Human Pre-catalytic Spliceosome (pre-B complex)

Summary for 6AH0

• Entry DOI: 10.2210/pdb6ah0/pdb
• EMDB information: 9621
• Descriptor: U5snRNA, Small nuclear ribonucleoprotein Sm D1, U6snRNA, ... (46 entities in total)
• Functional Keywords: spliceosome, splicing
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 57
• Total formula weight: 2500755.09

Authors

Zhan, X.,Yan, C.,Zhang, X.,Shi, Y. (deposition date: 2018-08-15, release date: 2018-11-14, Last modification date: 2024-03-27)

Primary citation

Zhan, X.,Yan, C.,Zhang, X.,Lei, J.,Shi, Y.
Structures of the human pre-catalytic spliceosome and its precursor spliceosome.
Cell Res., 28:1129-1140, 2018

PubMed Abstract: The pre-catalytic spliceosome (B complex) is preceded by its precursor spliceosome (pre-B complex) and followed by the activated spliceosome (B complex). The pre-B-to-B and B-to-B transitions are driven by the ATPase/helicases Prp28 and Brr2, respectively. In this study, we report the cryo-electron microscopy structures of the human pre-B complex and the human B complex at an average resolution of 5.7 and 3.8 Å, respectively. In the pre-B complex, U1 and U2 small nuclear ribonucleoproteins (snRNPs) associate with two edges of the tetrahedron-shaped U4/U6.U5 tri-snRNP. The pre-mRNA is yet to be recognized by U5 or U6 small nuclear RNA (snRNA), and loop I of U5 snRNA remains unengaged. In the B complex, U1 snRNP and Prp28 are dissociated, the 5'-exon is anchored to loop I of U5 snRNA, and the 5'-splice site is recognized by U6 snRNA through duplex formation. In sharp contrast to S. cerevisiae, most components of U2 snRNP and tri-snRNP, exemplified by Brr2, undergo pronounced rearrangements in the human pre-B-to-B transition. Structural analysis reveals mechanistic insights into the assembly and activation of the human spliceosome.

PubMed: 30315277
DOI: 10.1038/s41422-018-0094-7

Experimental method

ELECTRON MICROSCOPY (5.7 Å)