7D59

cryo-EM structure of human RNA polymerase III in apo state

Summary for 7D59

• Entry DOI: 10.2210/pdb7d59/pdb
• Related: 7D58
• EMDB information: 30578
• Descriptor: DNA-directed RNA polymerase III subunit RPC1, DNA-directed RNA polymerases I, II, and III subunit RPABC5, DNA-directed RNA polymerases I and III subunit RPAC2, ... (19 entities in total)
• Functional Keywords: rna polymerase iii, transcription
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 17
• Total formula weight: 709131.13

Authors

Wang, Q.,Wan, F.,Lan, P.,Wu, J.,Lei, M. (deposition date: 2020-09-25, release date: 2021-02-17, Last modification date: 2024-03-27)

Primary citation

Wang, Q.,Li, S.,Wan, F.,Xu, Y.,Wu, Z.,Cao, M.,Lan, P.,Lei, M.,Wu, J.
Structural insights into transcriptional regulation of human RNA polymerase III.
Nat.Struct.Mol.Biol., 28:220-227, 2021

PubMed Abstract: RNA polymerase III (Pol III) synthesizes structured, essential small RNAs, such as transfer RNA, 5S ribosomal RNA and U6 small nuclear RNA. Pol III, the largest nuclear RNA polymerase, is composed of a conserved core region and eight constitutive regulatory subunits, but how these factors jointly regulate Pol III transcription remains unclear. Here, we present cryo-EM structures of human Pol III in both apo and elongating states, which unveil both an orchestrated movement during the apo-to-elongating transition and an unexpected apo state in which the RPC7 subunit tail occupies the DNA-RNA-binding cleft of Pol III, suggesting that RPC7 plays important roles in both autoinhibition and transcription initiation. The structures also reveal a proofreading mechanism for the TFIIS-like subunit RPC10, which stably retains its catalytic position in the secondary channel, explaining the high fidelity of Pol III transcription. Our work provides an integrated picture of the mechanism of Pol III transcription regulation.

PubMed: 33558766
DOI: 10.1038/s41594-021-00557-x

Experimental method

ELECTRON MICROSCOPY (3.1 Å)