scholarly journals SARS-CoV-2 Variant of Concern Substitutions Alter Spike Glycoprotein Receptor Binding Domain Structure and Stability

2021 ◽  
Author(s):  
Daniel L Moss ◽  
Jay Rappaport

The emergence of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) and the subsequent COVID-19 pandemic has significantly impacted the world not just with disease and death but also economic turmoil. The rapid development and deployment of extremely effective vaccines against SARS-CoV-2 has made the end of the pandemic a reality within reach. However, as the virus spreads it has acquired mutations; and thus, variants of concern have emerged that are more infectious and reduce the efficacy of existing vaccines. While promising efforts are underway to combat these variants, the evolutionary pressures leading to these variants are poorly understood. To that end, here we have studied the effects of three amino-acid substitutions on the structure and function of the SARS-CoV-2 spike glycoprotein receptor-binding domain found in several variants of concern such as B.1.1.7, B.1.351 and P.1 that are now circulating. We found that these substitutions alter the RBD structure and stability, as well as its ability to bind to ACE2, which may have opposing and compensatory effects. These findings provide new insights into how these Variants of Concern (VOC) may have been selected to optimize infectivity while maintaining the structure and stability of the receptor binding domain.

2021 ◽  
pp. 167357
Author(s):  
Andrey M. Grishin ◽  
Nataliya V. Dolgova ◽  
Shelby Landreth ◽  
Olivier Fisette ◽  
Ingrid J. Pickering ◽  
...  

2020 ◽  
Author(s):  
Kathleen M. McAndrews ◽  
Dara P. Dowlatshahi ◽  
Janine Hensel ◽  
Luis L. Ostrosky-Zeichner ◽  
Ramesh Papanna ◽  
...  

AbstractDiagnostic testing and evaluation of patient immunity against the novel severe acute respiratory syndrome (SARS) corona virus that emerged last year (SARS-CoV-2) are essential for health and economic crisis recovery of the world. It is suggested that potential acquired immunity against SARS-CoV-2 from prior exposure may be determined by detecting the presence of circulating IgG antibodies against viral antigens, such as the spike glycoprotein and its receptor binding domain (RBD). Testing our asymptomatic population for evidence of COVID-19 immunity would also offer valuable epidemiologic data to aid health care policies and health care management. Currently, there are over 100 antibody tests that are being used around the world without approval from the FDA or similar regulatory bodies, and they are mostly for rapid and qualitative assessment, with different degrees of error rates. ELISA-based testing for sensitive and rigorous quantitative assessment of SARS-CoV-2 antibodies can potentially offer mechanistic insights into the COVID-19 disease and aid communities uniquely challenged by limited financial resources and access to commercial testing products. Employing recombinant SARS-CoV-2 RBD and spike protein generated in the laboratory, we devised a quantitative ELISA for the detection of circulating serum antibodies. Serum from twenty SARS-CoV-2 RT-PCR confirmed COVID-19 hospitalized patients were used to detect circulating IgG titers against SARS-CoV-2 spike protein and RBD. Quantitative detection of IgG antibodies to the spike glycoprotein or the RBD in patient samples was not always associated with faster recovery, compared to patients with borderline antibody response to the RBD. One patient who did not develop antibodies to the RBD completely recovered from COVID-19. In surveying 99 healthy donor samples (procured between 2017-February 2020), we detected RBD antibodies in one donor from February 2020 collection with three others exhibiting antibodies to the spike protein but not the RBD. Collectively, our study suggests that more rigorous and quantitative analysis, employing large scale samples sets, is required to determine whether antibodies to SARS-CoV-2 spike protein or RBD is associated with protection from COVID-19 disease. It is also conceivable that humoral response to SARS-CoV-2 spike protein or RBD works in association with adaptive T cell response to determine clinical sequela and severity of COVID-19 disease.


Author(s):  
Bipin Singh

: The recent outbreak of novel coronavirus (SARS-CoV-2 or 2019-nCoV) and its worldwide spread is posing one of the major threats to human health and the world economy. It has been suggested that SARS-CoV-2 is similar to SARSCoV based on the comparison of the genome sequence. Despite the genomic similarity between SARS-CoV-2 and SARSCoV, the spike glycoprotein and receptor binding domain in SARS-CoV-2 shows the considerable difference compared to SARS-CoV, due to the presence of several point mutations. The analysis of receptor binding domain (RBD) from recently published 3D structures of spike glycoprotein of SARS-CoV-2 (Yan, R., et al. (2020); Wrapp, D., et al. (2020); Walls, A. C., et al. (2020)) highlights the contribution of a few key point mutations in RBD of spike glycoprotein and molecular basis of its efficient binding with human angiotensin-converting enzyme 2 (ACE2).


2020 ◽  
Vol 120 (12) ◽  
pp. 1700-1715
Author(s):  
Courtney J. Mycroft-West ◽  
Dunhao Su ◽  
Isabel Pagani ◽  
Timothy R. Rudd ◽  
Stefano Elli ◽  
...  

AbstractThe dependence of development and homeostasis in animals on the interaction of hundreds of extracellular regulatory proteins with the peri- and extracellular glycosaminoglycan heparan sulfate (HS) is exploited by many microbial pathogens as a means of adherence and invasion. Heparin, a widely used anticoagulant drug, is structurally similar to HS and is a common experimental proxy. Exogenous heparin prevents infection by a range of viruses, including S-associated coronavirus isolate HSR1. Here, we show that heparin inhibits severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) invasion of Vero cells by up to 80% at doses achievable through prophylaxis and, particularly relevant, within the range deliverable by nebulisation. Surface plasmon resonance and circular dichroism spectroscopy demonstrate that heparin and enoxaparin, a low-molecular-weight heparin which is a clinical anticoagulant, bind and induce a conformational change in the spike (S1) protein receptor-binding domain (S1 RBD) of SARS-CoV-2. A library of heparin derivatives and size-defined fragments were used to probe the structural basis of this interaction. Binding to the RBD is more strongly dependent on the presence of 2-O or 6-O sulfate groups than on N-sulfation and a hexasaccharide is the minimum size required for secondary structural changes to be induced in the RBD. It is likely that inhibition of viral infection arises from an overlap between the binding sites of heparin/HS on S1 RBD and that of the angiotensin-converting enzyme 2. The results suggest a route for the rapid development of a first-line therapeutic by repurposing heparin and its derivatives as antiviral agents against SARS-CoV-2 and other members of the Coronaviridae.


Cell Reports ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. 441-452 ◽  
Author(s):  
Senyan Zhang ◽  
Panpan Zhou ◽  
Pengfei Wang ◽  
Yangyang Li ◽  
Liwei Jiang ◽  
...  

2021 ◽  
Vol 01 ◽  
Author(s):  
Sharuk L. Khan ◽  
Falak A. Siddiqui ◽  
Mohd Sayeed Shaikh ◽  
Nitin V. Nema ◽  
Aijaz A. Shaikh

Background: COVID-19 (SARS-CoV-2 infection) has affected almost every region of the world. Presently, there is no defined line of treatment available for it. Triphala is already proven to have a safe biological window and well known for its antioxidant and immunomodulatory properties. Objective: Present work has been carried out to study Triphala's effectiveness for the treatment of COVID-19. Methods: The Receptor-binding domain (RBD) of SARS-CoV-2 Spike Glycoprotein responsible for the invasion into the host cell, which leads to further infection. The molecular docking (MD) was performed to explore the binding affinities (kcal/mol) of Triphala's chemical constituents and compared them with the existing drugs under investigation for the treatment of COVID-19 epidemiology. Results: Chebulinic acid binding affinity -8.5 kcal/mol with the formation of 10 hydrogen bonds. Almost all the major chemical constituents have formed two or more hydrogen bonds with RBD of SARS-CoV-2 Spike Glycoprotein. Conclusion: The present study showed that Triphala might perform vital roles in the treatment of COVID-19 and expand its usefulness to physicians to treat this illness. There is a need to complete the in-vitro, in-vivo biological testing of Triphala on SARS-CoV-2 disease to create more quality data. The binding mode of Chebulinic acid in the allosteric cavity allows a better understanding of RBD of SARS-CoV-2 Spike Glycoprotein target and provides insight for the design of new inhibitors. Triphala is already proven to have a safe biological window, which indicates we can skip the pre-clinical trials. Apart from this, Triphala is well known for its antioxidant properties, which ultimately improves the immunity of the COVID-19 patient.


2021 ◽  
Author(s):  
Kun Qu ◽  
Xiaoli Xiong ◽  
Katarzyna A. Ciazynska ◽  
Andrew P. Carter ◽  
John A. G. Briggs

AbstractThe spike protein (S) of SARS-CoV-2 has been observed in three distinct pre-fusion conformations: locked, closed and open. Of these, the locked conformation was not previously observed for SARS-CoV-1 S and its function remains poorly understood. Here we engineered a SARS-CoV-2 S protein construct “S-R/x3” to arrest SARS-CoV-2 spikes in the locked conformation by a disulfide bond. Using this construct we determined high-resolution structures revealing two distinct locked states, with or without the D614G substitution that has become fixed in the globally circulating SARS-CoV-2 strains. The D614G mutation induces a structural change in domain D from locked-1 to locked-2 conformation to alter spike dynamics, promoting transition into the closed conformation from which opening of the receptor binding domain is permitted. The transition from locked to closed conformations is additionally promoted by a change from low to neutral pH. We propose that the locked conformations of S are present in the acidic cellular compartments where virus is assembled and egresses. In this model, release of the virion into the neutral pH extracellular space would favour transition to the closed form which itself can stochastically transition into the open form. The S-R/x3 construct provides a tool for the further structural and functional characterization of the locked conformations of S, as well as how sequence changes might alter S assembly and regulation of receptor binding domain dynamics.


2020 ◽  
Author(s):  
LAMIAE ELKHATTABI ◽  
Hicham Charoute ◽  
Rachid Saile ◽  
Abdelhamid Barakat

The novel COVID-19 pandemic is now a health threat, with a deep-felt impact worldwide. The new coronavirus 2019 (2019 n-Cov) binds to host human receptors through Receptor Binding Domain RBD of Spike glycoprotein (S), making it a prominent drug target. The present study aims to identify new potential hits that can inhibit the S protein using in silico approaches. Several natural and synthetics compounds (antiasthmatics, Antiviral, Antimalarial, Antibacterial, Anti-Inflammatory, cyclic peptide, and cyclic bis) were screened by molecular docking using AutoDock Vina. Additionally, we tested calcitriol and three known drugs (Azithromycin, HydroxyChloroquine, and Chloroquine ) against the spike protein to found if they have any direct interaction.<br>Our finding consists of 4 potential synthetic compounds from PubChem database, known for their antiasthmatic effects, that show highly binding energies each (-8.6 kcal/mol, 7.7kcal/mol, -7.2 kcal/mol and -7.0 kcal/mol). Another 5 natural compounds from the South African natural sources database (SANCDB) that bind to RBD of Spike with significant energy each: (Marchantin C with -7.3 kcal/mol, Riccardin C with -7.0 kcal/mol, Digitoxigenin-glucoside with -6.9 kcal/mol, D-Friedoolean-14-en-oic acid with -6.8 kcal/mol and, Spongotine A with -6.7 kcal/mol). The FaF-Drugs server was used to evaluate the drug-like properties of the identified compounds. Additionally, Calcitriol, Azithromycin, and HydroxyChloroquine have an appreciable binding affinity to 2019-nCoV S, suggesting a possible mechanism of action. Using in silico approaches like molecular docking and pharmacokinetic properties, we showed new potential inhibitors. Our findings need further analysis, and chemical design for more effective derivatives of these compounds speculated to disrupt the viral recognition of host receptors.


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