6TPS

early intermediate RNA Polymerase I Pre-initiation complex - eiPIC

Summary for 6TPS

• Entry DOI: 10.2210/pdb6tps/pdb
• EMDB information: 10544
• Descriptor: DNA-directed RNA polymerase I subunit RPA190, DNA-directed RNA polymerases I, II, and III subunit RPABC5, DNA-directed RNA polymerases I and III subunit RPAC2, ... (24 entities in total)
• Functional Keywords: transcription initiation, ribosome biosynthesis, rna polymerase i, transcription
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c); More
• Total number of polymer chains: 22
• Total formula weight: 880407.53

Authors

Pilsl, M.,Engel, C. (deposition date: 2019-12-14, release date: 2020-03-18, Last modification date: 2024-05-22)

Primary citation

Pilsl, M.,Engel, C.
Structural basis of RNA polymerase I pre-initiation complex formation and promoter melting.
Nat Commun, 11:1206-1206, 2020

PubMed Abstract: Transcription of the ribosomal RNA precursor by RNA polymerase (Pol) I is a prerequisite for the biosynthesis of ribosomes in eukaryotes. Compared to Pols II and III, the mechanisms underlying promoter recognition, initiation complex formation and DNA melting by Pol I substantially diverge. Here, we report the high-resolution cryo-EM reconstruction of a Pol I early initiation intermediate assembled on a double-stranded promoter scaffold that prevents the establishment of downstream DNA contacts. Our analyses demonstrate how efficient promoter-backbone interaction is achieved by combined re-arrangements of flexible regions in the 'core factor' subunits Rrn7 and Rrn11. Furthermore, structure-function analysis illustrates how destabilization of the melted DNA region correlates with contraction of the polymerase cleft upon transcription activation, thereby combining promoter recruitment with DNA-melting. This suggests that molecular mechanisms and structural features of Pol I initiation have co-evolved to support the efficient melting, initial transcription and promoter clearance required for high-level rRNA synthesis.

PubMed: 32139698
DOI: 10.1038/s41467-020-15052-y

Experimental method

ELECTRON MICROSCOPY (3.54 Å)