Ensemble cryo-EM reveals conformational states of the nsp13 helicase in the SARS-CoV-2 helicase replication-transcription complex.

Autor: Chen J; Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA., Wang Q; D. E. Shaw Research, New York, NY, USA., Malone B; Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA., Llewellyn E; Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA., Pechersky Y; D. E. Shaw Research, New York, NY, USA., Maruthi K; The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA., Eng ET; The National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY, USA., Perry JK; Gilead Sciences, Inc., Foster City, CA, USA., Campbell EA; Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA., Shaw DE; D. E. Shaw Research, New York, NY, USA. David.Shaw@DEShawResearch.com.; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA. David.Shaw@DEShawResearch.com., Darst SA; Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA. darst@rockefeller.edu.
Jazyk: angličtina
Zdroj: Nature structural & molecular biology [Nat Struct Mol Biol] 2022 Mar; Vol. 29 (3), pp. 250-260. Date of Electronic Publication: 2022 Mar 08.
DOI: 10.1038/s41594-022-00734-6
Abstrakt: 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 2 -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 2 -RTC, revealing four distinct conformational states of the helicases. The results indicate a mechanism for the nsp13 2 -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.
(© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)
Databáze: MEDLINE
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