7RDZ

SARS-CoV-2 replication-transcription complex bound to nsp13 helicase - nsp13(2)-RTC - apo class

Summary for 7RDZ

• Entry DOI: 10.2210/pdb7rdz/pdb
• EMDB information: 24428
• Descriptor: RNA-directed RNA polymerase, Non-structural protein 8, Non-structural protein 7, ... (9 entities in total)
• Functional Keywords: rna-dependent rna polymerase, viral replication-transcription complex, transcription, viral proteins, replication-transcription complex, replication/transcription
• Biological source: Severe acute respiratory syndrome coronavirus 2 (2019-nCoV); More
• Total number of polymer chains: 8
• Total formula weight: 324995.74

Authors

Chen, J.,Malone, B.,Campbell, E.A.,Darst, S.A. (deposition date: 2021-07-12, release date: 2021-11-24, Last modification date: 2024-06-05)

Primary citation

Chen, J.,Wang, Q.,Malone, B.,Llewellyn, E.,Pechersky, Y.,Maruthi, K.,Eng, E.T.,Perry, J.K.,Campbell, E.A.,Shaw, D.E.,Darst, S.A.
Ensemble cryo-EM reveals conformational states of the nsp13 helicase in the SARS-CoV-2 helicase replication-transcription complex.
Nat.Struct.Mol.Biol., 29:250-260, 2022

PubMed Abstract: The SARS-CoV-2 nonstructural proteins coordinate genome replication and gene expression. Structural analyses revealed the basis for coupling of the essential nsp13 helicase with the RNA-dependent RNA polymerase (RdRp) where the holo-RdRp and RNA substrate (the replication-transcription complex or RTC) associated with two copies of nsp13 (nsp13-RTC). One copy of nsp13 interacts with the template-RNA in an opposing polarity to the RdRp and is envisaged to drive the RdRp backward on the RNA template (backtracking), prompting questions as to how the RdRp can efficiently synthesize RNA in the presence of nsp13. Here we use cryogenic-electron microscopy and molecular dynamics simulations to analyze the nsp13-RTC, revealing four distinct conformational states of the helicases. The results indicate a mechanism for the nsp13-RTC to turn backtracking on and off, using an allosteric mechanism to switch between RNA synthesis or backtracking in response to stimuli at the RdRp active site.

PubMed: 35260847
DOI: 10.1038/s41594-022-00734-6

Experimental method

ELECTRON MICROSCOPY (3.6 Å)