tetano
Editor, Senior Moderator
J Mol Biol
. 2021 Nov 12;167357.
doi: 10.1016/j.jmb.2021.167357. Online ahead of print.
Disulfide bonds play a critical role in the structure and function of the receptor-binding domain of the SARS-CoV-2 Spike antigen
Andrey M Grishin[SUP] 1 [/SUP], Nataliya V Dolgova[SUP] 2 [/SUP], Shelby Landreth[SUP] 3 [/SUP], Olivier Fisette[SUP] 4 [/SUP], Ingrid J Pickering[SUP] 5 [/SUP], Graham N George[SUP] 5 [/SUP], Darryl Falzarano[SUP] 6 [/SUP], Miroslaw Cygler[SUP] 7 [/SUP]
Affiliations
Abstract
The current coronavirus pandemic is exerting a tremendously detrimental impact on global health. The Spike proteins of coronaviruses, responsible for cell receptor binding and viral internalization, possess multiple and frequently conserved disulfide bonds raising the question about their role in these proteins. Here, we present a detailed structural and functional investigation of the disulfide bonds of the SARS-CoV-2 Spike receptor-binding domain (RBD). Molecular dynamics simulations of the RBD predict increased flexibility of the surface loops when the four disulfide bonds of the domain are reduced. This flexibility is particularly prominent for the disulfide bond-containing surface loop (residues 456-490) that participates in the formation of the interaction surface with the Spike cell receptor ACE2. In vitro, disulfide bond reducing agents affect the RBD secondary structure, lower its melting temperature from 52°C to 36-39°C and decrease its binding affinity to ACE2 by two orders of magnitude at 37°C. Consistent with these in vitro findings, the reducing agents tris(2-carboxyethyl)phosphine (TCEP) and dithiothreitol (DTT) were able to inhibit viral replication at low millimolar levels in cell-based assays. Our research demonstrates the mechanism by which the disulfide bonds contribute to the molecular structure of the RBD of the Spike protein, allowing the RBD to execute its viral function.
Keywords: ACE2; RBD; SARS-CoV-2; Spike protein, thiol-reducing agent; disulfide bond; disulfide-reducing agent; receptor-binding domain; sulfhydryl group.
. 2021 Nov 12;167357.
doi: 10.1016/j.jmb.2021.167357. Online ahead of print.
Disulfide bonds play a critical role in the structure and function of the receptor-binding domain of the SARS-CoV-2 Spike antigen
Andrey M Grishin[SUP] 1 [/SUP], Nataliya V Dolgova[SUP] 2 [/SUP], Shelby Landreth[SUP] 3 [/SUP], Olivier Fisette[SUP] 4 [/SUP], Ingrid J Pickering[SUP] 5 [/SUP], Graham N George[SUP] 5 [/SUP], Darryl Falzarano[SUP] 6 [/SUP], Miroslaw Cygler[SUP] 7 [/SUP]
Affiliations
- PMID: 34780781
- DOI: 10.1016/j.jmb.2021.167357
Abstract
The current coronavirus pandemic is exerting a tremendously detrimental impact on global health. The Spike proteins of coronaviruses, responsible for cell receptor binding and viral internalization, possess multiple and frequently conserved disulfide bonds raising the question about their role in these proteins. Here, we present a detailed structural and functional investigation of the disulfide bonds of the SARS-CoV-2 Spike receptor-binding domain (RBD). Molecular dynamics simulations of the RBD predict increased flexibility of the surface loops when the four disulfide bonds of the domain are reduced. This flexibility is particularly prominent for the disulfide bond-containing surface loop (residues 456-490) that participates in the formation of the interaction surface with the Spike cell receptor ACE2. In vitro, disulfide bond reducing agents affect the RBD secondary structure, lower its melting temperature from 52°C to 36-39°C and decrease its binding affinity to ACE2 by two orders of magnitude at 37°C. Consistent with these in vitro findings, the reducing agents tris(2-carboxyethyl)phosphine (TCEP) and dithiothreitol (DTT) were able to inhibit viral replication at low millimolar levels in cell-based assays. Our research demonstrates the mechanism by which the disulfide bonds contribute to the molecular structure of the RBD of the Spike protein, allowing the RBD to execute its viral function.
Keywords: ACE2; RBD; SARS-CoV-2; Spike protein, thiol-reducing agent; disulfide bond; disulfide-reducing agent; receptor-binding domain; sulfhydryl group.