9FSQ
RNA Polymerase III Class III Melting Pre-Initiation Complex (MC)
Summary for 9FSQ
| Entry DOI | 10.2210/pdb9fsq/pdb |
| EMDB information | 50732 |
| Descriptor | DNA-directed RNA polymerase III subunit RPC1, DNA-directed RNA polymerase III subunit RPC10, DNA-directed RNA polymerases I and III subunit RPAC1, ... (28 entities in total) |
| Functional Keywords | rna polymerase iii, snapc, tfiiib, snrna, transcription |
| Biological source | Homo sapiens (human) More |
| Total number of polymer chains | 25 |
| Total formula weight | 1149062.41 |
| Authors | Shah, S.Z.,Ramsay, E.P.,Cecatiello, V.,Perry, T.N.,Vannini, A. (deposition date: 2024-06-21, release date: 2025-01-15) |
| Primary citation | Shah, S.Z.,Perry, T.N.,Graziadei, A.,Cecatiello, V.,Kaliyappan, T.,Misiaszek, A.D.,Muller, C.W.,Ramsay, E.P.,Vannini, A. Structural insights into distinct mechanisms of RNA polymerase II and III recruitment to snRNA promoters. Nat Commun, 16:141-141, 2025 Cited by PubMed Abstract: RNA polymerase III (Pol III) transcribes short, essential RNAs, including the U6 small nuclear RNA (snRNA). At U6 snRNA genes, Pol III is recruited by the snRNA Activating Protein Complex (SNAPc) and a Brf2-containing TFIIIB complex, forming a pre-initiation complex (PIC). Uniquely, SNAPc also recruits Pol II at the remaining splicesosomal snRNA genes (U1, 2, 4 and 5). The mechanism of SNAPc cross-polymerase engagement and the role of the SNAPC2 and SNAPC5 subunits remain poorly defined. Here, we present cryo-EM structures of the full-length SNAPc-containing Pol III PIC assembled on the U6 snRNA promoter in the open and melting states at 3.2-4.2 Å resolution. The structural comparison revealed differences with the Saccharomyces cerevisiae Pol III PIC and the basis of selective SNAPc engagement within Pol III and Pol II PICs. Additionally, crosslinking mass spectrometry localizes SNAPC2 and SNAPC5 near the promoter DNA, expanding upon existing descriptions of snRNA Pol III PIC structure. PubMed: 39747245DOI: 10.1038/s41467-024-55553-8 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.51 Å) |
Structure validation
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