7RDQ

Cryo-EM structure of Thermus thermophilus reiterative transcription complex with 11nt oligo-G RNA

Summary for 7RDQ

• Entry DOI: 10.2210/pdb7rdq/pdb
• Related: 4g7h 7MLB 7MLJ
• EMDB information: 24424
• Descriptor: DNA-directed RNA polymerase subunit alpha, ZINC ION, DNA-directed RNA polymerase subunit beta, ... (10 entities in total)
• Functional Keywords: thermus thermophilus, transcription initiation, transcription
• Biological source: Thermus thermophilus HB8; More
• Total number of polymer chains: 9
• Total formula weight: 451114.38

Authors

Liu, Y.,Ebright, R.H. (deposition date: 2021-07-10, release date: 2022-02-02, Last modification date: 2024-06-05)

Primary citation

Liu, Y.,Yu, L.,Pukhrambam, C.,Winkelman, J.T.,Firlar, E.,Kaelber, J.T.,Zhang, Y.,Nickels, B.E.,Ebright, R.H.
Structural and mechanistic basis of reiterative transcription initiation.
Proc.Natl.Acad.Sci.USA, 119:-, 2022

PubMed Abstract: Reiterative transcription initiation, observed at promoters that contain homopolymeric sequences at the transcription start site, generates RNA products having 5' sequences noncomplementary to the DNA template. Here, using crystallography and cryoelectron microscopy to define structures, protein-DNA photocrosslinking to map positions of RNAP leading and trailing edges relative to DNA, and single-molecule DNA nanomanipulation to assess RNA polymerase (RNAP)-dependent DNA unwinding, we show that RNA extension in reiterative transcription initiation 1) occurs without DNA scrunching; 2) involves a short, 2- to 3-bp, RNA-DNA hybrid; and 3) generates RNA that exits RNAP through the portal by which scrunched nontemplate-strand DNA exits RNAP in standard transcription initiation. The results establish that, whereas RNA extension in standard transcription initiation proceeds through a scrunching mechanism, RNA extension in reiterative transcription initiation proceeds through a slippage mechanism, with slipping of RNA relative to DNA within a short RNA-DNA hybrid, and with extrusion of RNA from RNAP through an alternative RNA exit.

PubMed: 35082149
DOI: 10.1073/pnas.2115746119

Experimental method

ELECTRON MICROSCOPY (3 Å)