9NH6
CRYO-EM STRUCTURE OF HUMAN U7 SNRNP WITH METHYLATED noncleavable H2A* SUBSTRATE PRE-MRNA (COMPOSITE MAP)
Summary for 9NH6
| Entry DOI | 10.2210/pdb9nh6/pdb |
| EMDB information | 49403 |
| Descriptor | Small nuclear ribonucleoprotein Sm D3, Symplekin, Cleavage stimulation factor subunit 3, ... (14 entities in total) |
| Functional Keywords | methylated rna, 3' end processing, u7 snrnp, histone pre-mrna, rna binding protein, rna binding protein-rna complex, rna binding protein/rna |
| Biological source | Homo sapiens (human) More |
| Total number of polymer chains | 13 |
| Total formula weight | 438218.34 |
| Authors | |
| Primary citation | Desotell, A.,Marzluff, W.F.,Dominski, Z.,Tong, L. An N-terminal helix of Lsm11 stabilizes CPSF73 in U7 snRNP for histone pre-mRNA 3'-end processing. Nucleic Acids Res., 54:-, 2026 Cited by PubMed Abstract: The U7 snRNP (small nuclear ribonucleoprotein) is responsible for the 3'-end processing of replication-dependent histone messenger RNA precursors (pre-mRNAs). A helix in the Lsm11 N-terminal extension contacts the metallo-β-lactamase domain of the U7 snRNP endonuclease CPSF73. We mutated or deleted this helix and found that the mutant machineries had substantially reduced cleavage activity toward the pre-mRNA. Our cryo-electron microscopy (cryo-EM) studies indicated that the helix was important for helping to hold CPSF73 in its correct position for the cleavage reaction. We also reconstituted a wild-type U7 snRNP in complex with a methylated, noncleavable pre-mRNA. We observed that CPSF73 could achieve an open conformation independent of RNA binding to its active site. Finally, we found that a previously uninterpreted EM density for a small helix at the CPSF73-CPSF100 interface belonged to the C-terminal end of CstF77, copurified from insect cells and highly conserved among CstF77 homologs. This CstF77 binding site had a small effect on the cleavage activity of U7 snRNP. Overall, our studies have revealed the importance of the conserved helix in the Lsm11 N-terminal extension for U7 snRNP, provided structural evidence that CPSF73 can achieve an open, active conformation without RNA binding in its active site, and identified a previously unknown binding site for CstF77 in CPSF100. PubMed: 41495886DOI: 10.1093/nar/gkaf1442 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.82 Å) |
Structure validation
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