7KRP

Structure of SARS-CoV-2 backtracked complex complex bound to nsp13 helicase - BTC (local refinement)

Summary for 7KRP

• Entry DOI: 10.2210/pdb7krp/pdb
• EMDB information: 23007 23008 23009
• 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, transferase-rna complex, transferase/rna
• Biological source: Severe acute respiratory syndrome coronavirus 2 (2019-nCoV); More
• Total number of polymer chains: 6
• Total formula weight: 193316.77

Authors

Chen, J.,Malone, B.,Campbell, E.A.,Darst, S.A. (deposition date: 2020-11-20, release date: 2021-04-21, Last modification date: 2025-05-21)

Primary citation

Malone, B.,Chen, J.,Wang, Q.,Llewellyn, E.,Choi, Y.J.,Olinares, P.D.B.,Cao, X.,Hernandez, C.,Eng, E.T.,Chait, B.T.,Shaw, D.E.,Landick, R.,Darst, S.A.,Campbell, E.A.
Structural basis for backtracking by the SARS-CoV-2 replication-transcription complex.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: Backtracking, the reverse motion of the transcriptase enzyme on the nucleic acid template, is a universal regulatory feature of transcription in cellular organisms but its role in viruses is not established. Here we present evidence that backtracking extends into the viral realm, where backtracking by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) may aid viral transcription and replication. Structures of SARS-CoV-2 RdRp bound to the essential nsp13 helicase and RNA suggested the helicase facilitates backtracking. We use cryo-electron microscopy, RNA-protein cross-linking, and unbiased molecular dynamics simulations to characterize SARS-CoV-2 RdRp backtracking. The results establish that the single-stranded 3' segment of the product RNA generated by backtracking extrudes through the RdRp nucleoside triphosphate (NTP) entry tunnel, that a mismatched nucleotide at the product RNA 3' end frays and enters the NTP entry tunnel to initiate backtracking, and that nsp13 stimulates RdRp backtracking. Backtracking may aid proofreading, a crucial process for SARS-CoV-2 resistance against antivirals.

PubMed: 33883267
DOI: 10.1073/pnas.2102516118

Experimental method

ELECTRON MICROSCOPY (3.2 Å)