scholarly journals Multimerization- and glycosylation-dependent receptor binding of SARS-CoV-2 spike proteins

2020 ◽  
Author(s):  
Kim M. Bouwman ◽  
Ilhan Tomris ◽  
Hannah L. Turner ◽  
Roosmarijn van der Woude ◽  
Gerlof P. Bosman ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Cell Lines ◽  
Receptor Binding ◽  
Expression Profiles ◽  
Spike Protein ◽  
Binding Studies ◽  
Binding Properties ◽  
Experimental Animals ◽  
High Mannose ◽  
Mutant Cells

Receptor binding studies using recombinant SARS-CoV proteins have been hampered due to challenges in approaches creating spike protein or domains thereof, that recapitulate receptor binding properties of native viruses. We hypothesized that trimeric RBD proteins would be suitable candidates to study receptor binding properties of SARS-CoV-1 and -2. Here we created monomeric and trimeric fluorescent RBD proteins, derived from adherent HEK293T, as well as in GnTI mutant cells, to analyze the effect of complex vs high mannose glycosylation on receptor binding. The results demonstrate that trimeric fully glycosylated proteins are superior in receptor binding compared to monomeric and immaturely glycosylated variants. Although differences in binding to commonly used cell lines were minimal between the different RBD preparations, substantial differences were observed when respiratory tissues of experimental animals were stained. The RBD trimers demonstrated distinct ACE2 expression profiles in bronchiolar ducts and confirmed the higher binding affinity of SARS-CoV-2 over SARS-CoV-1. Our results show that fully glycosylated trimeric RBD proteins are attractive to analyze receptor binding and explore ACE2 expression profiles in tissues.

scholarly journals Multimerization- and glycosylation-dependent receptor binding of SARS-CoV-2 spike proteins

2021 ◽  
Vol 17 (2) ◽  
pp. e1009282
Author(s):  
Kim M. Bouwman ◽  
Ilhan Tomris ◽  
Hannah L. Turner ◽  
Roosmarijn van der Woude ◽  
Tatiana M. Shamorkina ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Expression Profiles ◽  
Receptor Binding Domain ◽  
Binding Studies ◽  
Binding Properties ◽  
Experimental Animals ◽  
Trimeric Complex ◽  
High Mannose ◽  
Mutant Cells ◽  
Spike Proteins

Receptor binding studies on sarbecoviruses would benefit from an available toolkit of recombinant spike proteins, or domains thereof, that recapitulate receptor binding properties of native viruses. We hypothesized that trimeric Receptor Binding Domain (RBD) proteins would be suitable candidates to study receptor binding properties of SARS-CoV-1 and -2. Here we created monomeric and trimeric fluorescent RBD proteins, derived from adherent HEK293T, as well as in GnTI-/- mutant cells, to analyze the effect of complex vs high mannose glycosylation on receptor binding. The results demonstrate that trimeric, complex glycosylated proteins are superior in receptor binding compared to monomeric and immaturely glycosylated variants. Although differences in binding to commonly used cell lines were minimal between the different RBD preparations, substantial differences were observed when respiratory tissues of experimental animals were stained. The RBD trimers demonstrated distinct ACE2 expression profiles in bronchiolar ducts and confirmed the higher binding affinity of SARS-CoV-2 over SARS-CoV-1. Our results show that complex glycosylated trimeric RBD proteins are attractive to analyze sarbecovirus receptor binding and explore ACE2 expression profiles in tissues.

scholarly journals Bioinformatics analysis of SARS-CoV-2 RBD mutant variants and insights into antibody and ACE2 receptor binding

2021 ◽  
Author(s):  
Prashant Ranjan ◽  
Neha   ◽  
Chandra Devi ◽  
Parimal Das
Keyword(s):  
Binding Affinity ◽  
Receptor Binding ◽  
Double Mutant ◽  
Structural Changes ◽  
Protective Efficacy ◽  
Spike Protein ◽  
Wild Type ◽  
Current Vaccine ◽  
New Variant ◽  
The Impact

Prevailing COVID-19 vaccines are based on the spike protein of earlier SARS-CoV-2 strain that emerged in Wuhan, China. Continuously evolving nature of SARS-CoV-2 resulting emergence of new variant/s raise the risk of immune absconds. Several RBD (receptor-binding domain) variants have been reported to affect the vaccine efficacy considerably. In the present study, we performed in silico structural analysis of spike protein of double mutant (L452R & E484Q), a new variant of SARS-CoV-2 recently reported in India along with K417G variants and earlier reported RBD variants and found structural changes in RBD region after comparing with the wild type. Comparison of the binding affinity of the double mutant and earlier reported RBD variant for ACE2 (angiotensin 2 altered enzymes) receptor and CR3022 antibody with the wild-type strain revealed the lowest binding affinity of the double mutant for CR3022 among all other variants. These findings suggest that the newly emerged double mutant could significantly reduce the impact of the current vaccine which threatens the protective efficacy of current vaccine therapy.

scholarly journals V367F mutation in SARS-CoV-2 spike RBD emerging during the early transmission phase enhances viral infectivity through increased human ACE2 receptor binding affinity

2021 ◽  
Author(s):  
Junxian Ou ◽  
Zhonghua Zhou ◽  
Ruixue Dai ◽  
Jing Zhang ◽  
Shan Zhao ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Receptor Binding ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Critical Determinant ◽  
Evolutionary Trajectory ◽  
Receptor Binding Affinity ◽  
Protein Receptor ◽  
Novel Coronavirus ◽  
Transmission Phase

The current pandemic of COVID-19 is caused by a novel coronavirus SARS-CoV-2. The SARS-CoV-2 spike protein receptor-binding domain (RBD) is the critical determinant of viral tropism and infectivity. To investigate whether naturally occurring RBD mutations during the early transmission phase have altered the receptor binding affinity and infectivity, firstly we analyzed in silico the binding dynamics between SARS-CoV-2 RBD mutants and the human ACE2 receptor. Among 32,123 genomes of SARS-CoV-2 isolates (January through March, 2020), 302 non-synonymous RBD mutants were identified and clustered into 96 mutant types. The six dominant mutations were analyzed applying molecular dynamics simulations (MDS). The mutant type V367F continuously circulating worldwide displayed higher binding affinity to human ACE2 due to the enhanced structural stabilization of the RBD beta-sheet scaffold. The MDS also indicated that it would be difficult for bat SARS-like CoV to infect humans. However, the pangolin CoV is potentially infectious to humans. The increased infectivity of V367 mutants was further validated by performing receptor-ligand binding ELISA, surface plasmon resonance, and pseudotyped virus assays. Phylogenetic analysis of the genomes of V367F mutants showed that during the early transmission phase, most V367F mutants clustered more closely with the SARS-CoV-2 prototype strain than the dual-mutation variants (V367F + D614G) which may derivate from recombination. The analysis of critical RBD mutations provides further insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin under negative selection pressure and supports the continuing surveillance of spike mutations to aid in the development of new COVID-19 drugs and vaccines. Importance A novel coronavirus SARS-CoV-2 has caused the pandemic of COVID-19. The origin of SARS-CoV-2 was associated with zoonotic infections. The spike protein receptor-binding domain (RBD) is identified as the critical determinant of viral tropism and infectivity. Thus, whether the mutations in the RBD of the circulating SARS-CoV-2 isolates have altered the receptor binding affinity and made them more infectious, has been the research hotspot. Given that SARS-CoV-2 is a novel coronavirus, the significance of our research is in identifying and validating the RBD mutant types emerging during the early transmission phase and increasing human ACE2 receptor binding affinity and infectivity. Our study provides insights into the evolutionary trajectory of early SARS-CoV-2 variants of zoonotic origin. The continuing surveillance of RBD mutations with increased human ACE2 affinity in human or other animals is critical to the development of new COVID-19 drugs and vaccines against these variants during the sustained COVID-19 pandemic.

scholarly journals Cell entry mechanisms of SARS-CoV-2

2020 ◽  
Vol 117 (21) ◽  
pp. 11727-11734 ◽  
Author(s):  
Jian Shang ◽  
Yushun Wan ◽  
Chuming Luo ◽  
Gang Ye ◽  
Qibin Geng ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Receptor Binding ◽  
Immune Surveillance ◽  
Intervention Strategies ◽  
Cell Entry ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Wide Spread ◽  
Virus Surface ◽  
Protease Activation

A novel severe acute respiratory syndrome (SARS)-like coronavirus (SARS-CoV-2) is causing the global coronavirus disease 2019 (COVID-19) pandemic. Understanding how SARS-CoV-2 enters human cells is a high priority for deciphering its mystery and curbing its spread. A virus surface spike protein mediates SARS-CoV-2 entry into cells. To fulfill its function, SARS-CoV-2 spike binds to its receptor human ACE2 (hACE2) through its receptor-binding domain (RBD) and is proteolytically activated by human proteases. Here we investigated receptor binding and protease activation of SARS-CoV-2 spike using biochemical and pseudovirus entry assays. Our findings have identified key cell entry mechanisms of SARS-CoV-2. First, SARS-CoV-2 RBD has higher hACE2 binding affinity than SARS-CoV RBD, supporting efficient cell entry. Second, paradoxically, the hACE2 binding affinity of the entire SARS-CoV-2 spike is comparable to or lower than that of SARS-CoV spike, suggesting that SARS-CoV-2 RBD, albeit more potent, is less exposed than SARS-CoV RBD. Third, unlike SARS-CoV, cell entry of SARS-CoV-2 is preactivated by proprotein convertase furin, reducing its dependence on target cell proteases for entry. The high hACE2 binding affinity of the RBD, furin preactivation of the spike, and hidden RBD in the spike potentially allow SARS-CoV-2 to maintain efficient cell entry while evading immune surveillance. These features may contribute to the wide spread of the virus. Successful intervention strategies must target both the potency of SARS-CoV-2 and its evasiveness.

scholarly journals Structural Analysis And Molecular Characteristics of SARSCoV-2 Spike Protein Following S494P Point Mutation: Molecular Dynamics Study

2021 ◽  
Author(s):  
Mehr Ali Mahmood Janlou ◽  
Hassan sahebjamee ◽  
Shademan Shokravi
Keyword(s):  
Structural Analysis ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Conformational Changes ◽  
Spike Protein ◽  
Molecular Characteristics ◽  
Wild Type ◽  
Natural Mutation ◽  
The Stability ◽  
Different Strains

Abstract The emergence of some mutations in the SARS-CoV-2 receptor binding domain (RBD) can increase the spread and pathogenicity due to the conformational changes and increase the stability of Spike protein. Due to the formation of different strains of SARS-CoV-2 by mutations, and their catastrophic effect on public health, the study of the effect of mutations by scientists and researchers around the world is inevitable. According to available evidence, the S494P variant is observed in several SARS-CoV-2 strains from Michigan, USA. To investigate how the S494P natural mutation alters receptor binding affinity in RBD, we performed structural analysis of wild-type and mutant spike proteins using some bioinformatics and computational tools. The results show that S494P mutation increases the spike protein stability. Also, applying docking by HADDOCK displayed higher binding affinity to hACE2 for mutant spike than wild type possibly due to the increased β-strand and Turn secondary structures which increases surface accessibly surface area (SASA) and chance of interaction. The analysis of S494P as a critical RBD mutation may provide the continuing surveillance of spike mutations to aid in the development of COVID-19 drugs and vaccines.

scholarly journals 501Y.V2 and 501Y.V3 variants of SARS-CoV-2 lose binding to Bamlanivimab in vitro

2021 ◽  
Author(s):  
Haolin Liu ◽  
Pengcheng Wei ◽  
Qianqian Zhang ◽  
Zhongzhou Chen ◽  
Katja Aviszus ◽  
...  
Keyword(s):  
South Africa ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Binding Domain ◽  
Therapeutic Antibody ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Human Receptor

AbstractWe generated several versions of the receptor binding domain (RBD) of the Spike protein with mutations existing within newly emerging variants from South Africa and Brazil. We found that the mutant RBD with K417N, E484K, and N501Y exchanges has higher binding affinity to the human receptor compared to the wildtype RBD. This mutated version of RBD also completely abolishes the binding to a therapeutic antibody, Bamlanivimab, in vitro.

scholarly journals Structural remodeling of SARS-CoV-2 spike protein glycans reveals the regulatory roles in receptor binding affinity

2021 ◽  
Author(s):  
Yen-Pang Hsu ◽  
Debopreeti Mukherjee ◽  
Vladimir Shchurik ◽  
Alexey Makarov ◽  
Benjamin F. Mann
Keyword(s):  
Binding Affinity ◽  
Receptor Binding ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Receptor Binding Affinity ◽  
Protein Receptor ◽  
Regulatory Effects

AbstractGlycans of the SARS-CoV-2 spike protein are speculated to play functional roles in the infection processes as they extensively cover the protein surface and are highly conserved across the variants. To date, the spike protein has become the principal target for vaccine and therapeutic development while the exact effects of its glycosylation remain elusive. Experimental reports have described the heterogeneity of the spike protein glycosylation profile. Subsequent molecular simulation studies provided a knowledge basis of the glycan functions. However, there are no studies to date on the role of discrete glycoforms on the spike protein pathobiology. Building an understanding of its role in SARS-CoV-2 is important as we continue to develop effective medicines and vaccines to combat the disease. Herein, we used designed combinations of glycoengineering enzymes to simplify and control the glycosylation profile of the spike protein receptor-binding domain (RBD). Measurements of the receptor binding affinity revealed the regulatory effects of the RBD glycans. Remarkably, opposite effects were observed from differently remodeled glycans, which presents a potential strategy for modulating the spike protein behaviors through glycoengineering. Moreover, we found that the reported anti-SARS-CoV-(2) antibody, S309, neutralizes the impact of different RBD glycoforms on the receptor binding affinity. Overall, this work reports the regulatory roles that glycosylation plays in the interaction between the viral spike protein and host receptor, providing new insights into the nature of SARS-CoV-2. Beyond this study, enzymatic remodeling of glycosylation offers the opportunity to understand the fundamental role of specific glycoforms on glycoconjugates across molecular biology.Covert art LegendsThe glycosylation of the SARS-CoV-2 spike protein receptor-binding domain has regulatory effects on the receptor binding affinity. Sialylation or not determines the “stabilizing” or “destabilizing” effect of the glycans. (Protein structure model is adapted from Protein Data Bank: 6moj. The original model does not contain the glycan structure.)SignificanceGlycans extensively cover the surface of SARS-CoV-2 spike (S) protein but the relationships between the glycan structures and the protein pathological behaviors remain elusive. Herein, we simplified and harmonized the glycan structures in the S protein receptor-binding domain and reported their regulatory roles in human receptor interaction. Opposite regulatory effects were observed and were determined by discrete glycan structures, which can be neutralized by the reported S309 antibody binding to the S protein. This report provides new insight into the mechanism of SARS-CoV-2 S protein infection as well as S309 neutralization.

scholarly journals Impact of the Double Mutants on Spike Protein of SARS-CoV-2 B.1.617 Lineage to the Human ACE2 Receptor Binding: A Structural Insight

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2295
Author(s):  
Mohd Imran Khan ◽  
Mohammad Hassan Baig ◽  
Tanmoy Mondal ◽  
Mohammed Alorabi ◽  
Tanuj Sharma ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Receptor Binding ◽  
Immune Escape ◽  
Principal Component ◽  
Spike Protein ◽  
Human Host ◽  
Recent Emergence ◽  
Novel Variants ◽  
Structural Insight ◽  
The Impact

The recent emergence of novel SARS-CoV-2 variants has threatened the efforts to contain the COVID-19 pandemic. The emergence of these “variants of concern” has increased viral transmissibility or immune escape and has supplanted the ancestral strains. The novel variants harbored by the B.1.617 lineage (Kappa and Delta) carry mutations within the receptor-binding domain of spike (S) protein (L452R + E484Q and L452R + T478K), the region binding to the host receptor. The double mutations carried by these novel variants are primarily responsible for an upsurge number of COVID-19 cases in India. In this study, we thoroughly investigated the impact of these double mutations on the binding capability to the human host receptor. We performed several structural analyses and found that the studied double mutations increase the binding affinity of the spike protein to the human host receptor (ACE2). Furthermore, our study showed that these double mutants might be a dominant contributor enhancing the receptor-binding affinity of SARS-CoV-2 and consequently making it more stable. We also investigated the impact of these mutations on the binding affinity of two monoclonal antibodies (Abs) (2-15 and LY-CoV555) and found that the presence of the double mutations also hinders its binding with the studied Abs. The principal component analysis, free energy landscape, intermolecular interaction, and other investigations provided a deeper structural insight to better understand the molecular mechanism responsible for increased viral transmissibility of these variants.

scholarly journals Massively Multiplexed Affinity Characterization of Therapeutic Antibodies Against SARS-CoV-2 Variants

2021 ◽  
Author(s):  
Emily Engelhart ◽  
Randolph Lopez ◽  
Ryan Emerson ◽  
Charles Lin ◽  
Colleen Shikany ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Binding Affinity ◽  
Receptor Binding ◽  
Viral Transmission ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Therapeutic Antibodies ◽  
Large Panel

AbstractAntibody therapies represent a valuable tool to reduce COVID-19 deaths and hospitalizations. Multiple antibody candidates have been granted emergency use authorization by the FDA and many more are in clinical trials. Most antibody therapies for COVID-19 are engineered to bind to the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein and disrupt its interaction with ACE2. Notably, several SARS-CoV-2 strains have accrued mutations throughout the RBD that improve ACE2 binding affinity, enhance viral transmission, and escape some existing antibody therapies. Here, we measure the binding affinity of 33 therapeutic antibodies against a large panel of SARS-CoV-2 variants and related strains of clinical significance to determine epitopic residues, determine which mutations result in loss of binding, and predict how future RBD variants may impact antibody efficacy.One-Sentence SummaryBy measuring protein binding in vitro, we identify which clinical antibodies retain binding to various mutant SARS-CoV-2 strains.

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