Cryo-EM structures and binding of mouse and human ACE2 to SARS-CoV-2 variants of concern indicate that mutations enabling immune escape could expand host range
This article has been Reviewed by the following groups
Listed in
- Evaluated articles (ScreenIT)
Abstract
Investigation of potential hosts of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is crucial to understanding future risks of spillover and spillback. SARS-CoV-2 has been reported to be transmitted from humans to various animals after requiring relatively few mutations.[1] There is significant interest in describing how the virus interacts with mice as they are well adapted to human environments, are used widely as infection models and can be infected.[2] Structural and binding data of the mouse ACE2 receptor with the Spike protein of newly identified SARS-CoV-2 variants are needed to better understand the impact of immune system evading mutations present in variants of concern (VOC). Previous studies have developed mouse-adapted variants and identified residues critical for binding to heterologous ACE2 receptors.[3,4] Here we report the cryo-EM structures of mouse ACE2 bound to trimeric Spike ectodomains of four different VOC: Beta, Omicron BA.1, Omicron BA.2.12.1 and Omicron BA.4/5. These variants represent the oldest to the newest variants known to bind the mouse ACE2 receptor. Our high-resolution structural data complemented with bio-layer interferometry (BLI) binding assays reveal a requirement for a combination of mutations in the Spike protein that enable binding to the mouse ACE2 receptor.
AUTHOR SUMMARY
The SARS-CoV-2 virus can infect different types of animals beyond humans. The virus uses its Spike protein on its surface to bind to cells. These cells have a protein called ACE2 that the Spike protein recognizes. Animals have slightly different ACE2 receptors compared to humans. Mice are widely used as a research animal and live in the same environments as humans so scientists are particularly interested. Understanding how Spike proteins binds to the mouse ACE2 receptor allows us to understand the impact of immune evading mutations found in new variants. We use a high resolution imaging technique called cryo-electron microscopy to look at how different Spike variants bind to the ACE2 receptor from mouse at a resolution where we can see the amino acids. We can see directly the individual amino acids and mutations on the Spike protein that interact with the mouse ACE2 receptor. Many of the mutations found in variants of concern also increase the strength of binding to the mouse ACE2 receptor. This result suggests that mutations in the Spike protein of future variants may have an additional effect in influencing how it binds to not only human ACE2 receptors but to mice and also different animals.
Article activity feed
-
-
-
SciScore for 10.1101/2021.12.27.474250: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
NIH rigor criteria are not applicable to paper type.Table 2: Resources
Recombinant DNA Sentences Resources Protein Production and Purification: RNA isolated from an anonymized leftover sample of a SARS-CoV-2 infected individual was reverse transcribed into cDNA and the Omicron Spike ectodomain was amplified by PCR, sequence verified and cloned into the nCoV-2P-F3CH2S plasmid, replacing the original wild-type Spike.5 Mutations stabilizing the Spike protein in the trimeric prefusion state were introduced simultaneously by PCR and In-Fusion cloning. nCoV-2P-F3CH2Ssuggested: NoneSoftware and Algorithms Sentences Resources Cryo-EM image processing: On-the-fly processing was first performed during data … SciScore for 10.1101/2021.12.27.474250: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
NIH rigor criteria are not applicable to paper type.Table 2: Resources
Recombinant DNA Sentences Resources Protein Production and Purification: RNA isolated from an anonymized leftover sample of a SARS-CoV-2 infected individual was reverse transcribed into cDNA and the Omicron Spike ectodomain was amplified by PCR, sequence verified and cloned into the nCoV-2P-F3CH2S plasmid, replacing the original wild-type Spike.5 Mutations stabilizing the Spike protein in the trimeric prefusion state were introduced simultaneously by PCR and In-Fusion cloning. nCoV-2P-F3CH2Ssuggested: NoneSoftware and Algorithms Sentences Resources Cryo-EM image processing: On-the-fly processing was first performed during data acquisition for evaluating the data quality during screening by using cryoSPARC live v3.3.1.4 The obtained ab-initio structures were used for better particle picking for template creation. cryoSPARCsuggested: (cryoSPARC, RRID:SCR_016501)15 These docked models were extended and rebuilt manually with refinement, using Coot and Phenix.34,35 Figures were prepared in UCSF Chimera and UCSF ChimeraX. Cootsuggested: (Coot, RRID:SCR_014222)Results from OddPub: Thank you for sharing your data.
Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
-