scholarly journals SARS-CoV-2 spike protein unlikely to bind to integrins via the Arg-Gly-Asp (RGD) motif of the Receptor Binding Domain: evidence from structural analysis and microscale accelerated molecular dynamics

2021 ◽  
Author(s):  
Houcemeddine Othman ◽  
Haifa Ben Messaoud ◽  
Oussema Khamessi ◽  
Hazem Ben Mabrouk ◽  
Kais Ghedira ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Analysis ◽  
Receptor Binding ◽  
Normal Mode Analysis ◽  
Protein Docking ◽  
Binding Domain ◽  
Mode Analysis ◽  
Receptor Binding Domain ◽  
Rgd Motif ◽  
Accelerated Molecular Dynamics

The Receptor Binding Domain (RBD) of SARS-CoV-2 virus harbors a sequence of Arg-Gly-Asp tripeptide named RGD motif, which has also been identified in extracellular matrix proteins that bind integrins as well as other disintegrins and viruses. Accordingly, integrins have been proposed as host receptors for SARS-CoV-2. The hypothesis was supported by sequence and structural analysis. However, given that the microenvironment of the RGD motif imposes structural hindrance to the protein-protein association, the validity of this hypothesis is still uncertain. Here, we used normal mode analysis, accelerated molecular dynamics microscale simulation, and protein-protein docking to investigate the putative role of RGD motif of SARS-CoV-2 RBD for interacting with integrins. We found, by molecular dynamics, that neither RGD motif nore its microenvironment show any significant conformational shift in the RBD structure. Highly populated clusters were used to run a protein-protein docking against three RGD-binding integrin types, showing no capability of the RBD domain to interact with the RGD binding site. Moreover, the free energy landscape revealed that the RGD conformation within RBD could not acquire an optimal geometry to allow the interaction with integrins. Our results highlighted different structural features of the RGD motif that may prevent its involvement in the interaction with integrins. We, therefore, suggest, in the case where integrins are confirmed to be the direct host receptors for SARS-CoV-2, a possible involvement of other residues to stabilize the interaction.

ReaxFF-based molecular dynamics simulation of the interaction between plasma ROS and the receptor-binding domain of the spike protein in the capsid protein of SARS-CoV-2

2021 ◽  
Author(s):  
Huichao Wang ◽  
Tong Zhao ◽  
Shuhui Yang ◽  
Liang Zou ◽  
Xiaolong Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Amino Acid ◽  
Capsid Protein ◽  
Receptor Binding ◽  
Hydrogen Abstraction ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Amino Acid Residues ◽  
Global Epidemic

Abstract Under the severe situation of the current global epidemic, researchers have been working hard to find a reliable way to suppress the infection of the virus and prevent the spread of the epidemic. Studies have shown that the recognition and binding of human angiotensin-converting enzyme 2 (ACE2) by the receptor-binding domain (BRD) of spike protein on the surface of SARS-CoV-2 is a crucial step for SARS-CoV-2 to invade human receptor cells, and blocking this process can inhibit the virus from invading human normal cells. Plasma treatment can disrupt the structure of the RBD and effectively block the binding process. However, the mechanism by which plasma blocks the recognition and binding between the two is not clear. In this study, reaction process between reactive oxygen species (ROS) in plasma and the molecular model of RBD was simulated using a reactive molecular dynamics method. The results showed that the destruction of RBD molecule by ROS was triggered by hydrogen abstraction reactions. O and OH abstracted H atoms from RBD, while the H atoms of H2O2 and HO2 were abstracted by RBD. The hydrogen abstraction resulted in the breakage of C-H, N-H, O-H and C=O bonds and the formation of C=C, C=N bonds. The addition reaction of OH increased the number of O-H bonds and caused the formation of C-O, N-O and O-H bonds. The dissociation of N-H bonds led to the destruction of the original structure of peptide bonds and amino acid residues, change the type of amino acid residues, and caused the conversion of N-C and N=C, C=O and C-O. The simulation partially elucidated the microscopic mechanism of the interaction between ROS in plasma and the capsid protein of SARS-CoV-2, providing theoretical support for the control of SARS-CoV-2 infection by plasma, a contribution to overcoming the global epidemic problem.

scholarly journals Can the SARS-CoV-2 Spike Protein Bind Integrins Independent of the RGD Sequence?

2021 ◽  
Vol 11 ◽  
Author(s):  
Christopher A. Beaudoin ◽  
Samir W. Hamaia ◽  
Christopher L.-H. Huang ◽  
Tom L. Blundell ◽  
Antony P. Jackson
Keyword(s):  
Receptor Binding ◽  
Conformational Changes ◽  
Sequence Similarity ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Binding Motifs ◽  
Rgd Motif ◽  
Rgd Sequence ◽  
Protein Receptor

The RGD motif in the Severe Acute Syndrome Coronavirus 2 (SARS-CoV-2) spike protein has been predicted to bind RGD-recognizing integrins. Recent studies have shown that the spike protein does, indeed, interact with αVβ3 and α5β1 integrins, both of which bind to RGD-containing ligands. However, computational studies have suggested that binding between the spike RGD motif and integrins is not favourable, even when unfolding occurs after conformational changes induced by binding to the canonical host entry receptor, angiotensin-converting enzyme 2 (ACE2). Furthermore, non-RGD-binding integrins, such as αx, have been suggested to interact with the SARS-CoV-2 spike protein. Other viral pathogens, such as rotaviruses, have been recorded to bind integrins in an RGD-independent manner to initiate host cell entry. Thus, in order to consider the potential for the SARS-CoV-2 spike protein to bind integrins independent of the RGD sequence, we investigate several factors related to the involvement of integrins in SARS-CoV-2 infection. First, we review changes in integrin expression during SARS-CoV-2 infection to identify which integrins might be of interest. Then, all known non-RGD integrin-binding motifs are collected and mapped to the spike protein receptor-binding domain and analyzed for their 3D availability. Several integrin-binding motifs are shown to exhibit high sequence similarity with solvent accessible regions of the spike receptor-binding domain. Comparisons of these motifs with other betacoronavirus spike proteins, such as SARS-CoV and RaTG13, reveal that some have recently evolved while others are more conserved throughout phylogenetically similar betacoronaviruses. Interestingly, all of the potential integrin-binding motifs, including the RGD sequence, are conserved in one of the known pangolin coronavirus strains. Of note, the most recently recorded mutations in the spike protein receptor-binding domain were found outside of the putative integrin-binding sequences, although several mutations formed inside and close to one motif, in particular, may potentially enhance binding. These data suggest that the SARS-CoV-2 spike protein may interact with integrins independent of the RGD sequence and may help further explain how SARS-CoV-2 and other viruses can evolve to bind to integrins.

scholarly journals Molecular Dynamics of SARS-CoV-2 Delta Variant Receptor Binding Domain in Complex with ACE2 Receptor

2021 ◽  
Author(s):  
Victor Padilla-Sanchez
Keyword(s):  
Molecular Dynamics ◽  
At Risk ◽  
Receptor Binding ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Virus Variant ◽  
Structural Interactions ◽  
The One ◽  
Shed Light ◽  
Human Receptor

COVID19 pandemic has disrupted our lives since December 2019 causing millions of infections and deaths worldwide. After more than a year we have vaccines that are effective in preventing the disease even though we are far from finished to vaccinate most of the population. Certain countries are doing better vaccinating people while others are far behind and if that is not enough new variants have appeared that put at risk our progress on defeating COVID19. The virus SARS-CoV-2 is mutating and many mutations change the spike glycoprotein which binds to the human receptor ACE2 sometimes making the virus more infectious and able to evade immunity. One virus variant of concern (VoC) is the one called delta which is becoming prevalent very quickly among new infections. The delta variant is a real threat for many people that are not vaccinated. Here I present molecular dynamics of the receptor binding domain in complex with its receptor ACE2 to shed light on the structural interactions that make this variant more dangerous.

scholarly journals Structural Analysis of Receptor Binding Domain Mutations in SARS-CoV-2 Variants of Concern that Modulate ACE2 and Antibody Binding

2021 ◽  
Author(s):  
Dhiraj Mannar ◽  
James W Saville ◽  
Xing Zhu ◽  
Shanti S. Srivastava ◽  
Alison M. Berezuk ◽  
...  
Keyword(s):  
Structural Analysis ◽  
South African ◽  
Receptor Binding ◽  
Antibody Binding ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Biochemical Assays ◽  
The Uk ◽  
Spike Proteins

SummaryThe recently emerged SARS-CoV-2 South African (B. 1.351) and Brazil/Japan (P.1) variants of concern (VoCs) include a key mutation (N501Y) found in the UK variant that enhances affinity of the spike protein for its receptor, ACE2. Additional mutations are found in these variants at residues 417 and 484 that appear to promote antibody evasion. In contrast, the Californian VoCs (B.1.427/429) lack the N501Y mutation, yet exhibit antibody evasion. We engineered spike proteins to express these RBD VoC mutations either in isolation, or in different combinations, and analyzed the effects using biochemical assays and cryo-EM structural analyses. Overall, our findings suggest that the emergence of new SARS-CoV-2 variant spikes can be rationalized as the result of mutations that confer either increased ACE2 affinity, increased antibody evasion, or both, providing a framework to dissect the molecular factors that drive VoC evolution.

scholarly journals Identification of an anti–SARS–CoV-2 receptor-binding domain–directed human monoclonal antibody from a naïve semisynthetic library

2020 ◽  
Vol 295 (36) ◽  
pp. 12814-12821 ◽  
Author(s):  
Hilal Ahmad Parray ◽  
Adarsh Kumar Chiranjivi ◽  
Shailendra Asthana ◽  
Naveen Yadav ◽  
Tripti Shrivastava ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Specific Binding ◽  
Human Monoclonal Antibody ◽  
Protein Docking ◽  
Binding Domain ◽  
Phage Library ◽  
Receptor Binding Domain ◽  
Single Chain ◽  
Phage Display Technology ◽  
Entry Points

There is a desperate need for safe and effective vaccines, therapies, and diagnostics for SARS– coronavirus 2 (CoV-2), the development of which will be aided by the discovery of potent and selective antibodies against relevant viral epitopes. Human phage display technology has revolutionized the process of identifying and optimizing antibodies, providing facile entry points for further applications. Herein, we use this technology to search for antibodies targeting the receptor-binding domain (RBD) of CoV-2. Specifically, we screened a naïve human semisynthetic phage library against RBD, leading to the identification of a high-affinity single-chain fragment variable region (scFv). The scFv was further engineered into two other antibody formats (scFv-Fc and IgG1). All three antibody formats showed high binding specificity to CoV-2 RBD and the spike antigens in different assay systems. Flow cytometry analysis demonstrated specific binding of the IgG1 format to cells expressing membrane-bound CoV-2 spike protein. Docking studies revealed that the scFv recognizes an epitope that partially overlaps with angiotensin-converting enzyme 2 (ACE2)–interacting sites on the CoV-2 RBD. Given its high specificity and affinity, we anticipate that these anti-CoV-2 antibodies will be useful as valuable reagents for accessing the antigenicity of vaccine candidates, as well as developing antibody-based therapeutics and diagnostics for CoV-2.

scholarly journals The flexibility of ACE2 in the context of SARS-CoV-2 infection

2020 ◽  
Author(s):  
E. P. Barros ◽  
L. Casalino ◽  
Z. Gaieb ◽  
A. C. Dommer ◽  
Y. Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Receptor Binding ◽  
Rational Design ◽  
Binding Domain ◽  
Full Length ◽  
Receptor Binding Domain ◽  
Spike Glycoprotein ◽  
Linker Region ◽  
Dynamics Simulations

AbstractThe COVID-19 pandemic has swept over the world in the past months, causing significant loss of life and consequences to human health. Although numerous drug and vaccine developments efforts are underway, many questions remain outstanding on the mechanism of SARS-CoV-2 viral association to angiotensin-converting enzyme 2 (ACE2), its main host receptor, and entry in the cell. Structural and biophysical studies indicate some degree of flexibility in the viral extracellular Spike glycoprotein and at the receptor binding domain-receptor interface, suggesting a role in infection. Here, we perform all-atom molecular dynamics simulations of the glycosylated, full-length membrane-bound ACE2 receptor, in both an apo and spike receptor binding domain (RBD) bound state, in order to probe the intrinsic dynamics of the ACE2 receptor in the context of the cell surface. A large degree of fluctuation in the full length structure is observed, indicating hinge bending motions at the linker region connecting the head to the transmembrane helix, while still not disrupting the ACE2 homodimer or ACE2-RBD interfaces. This flexibility translates into an ensemble of ACE2 homodimer conformations that could sterically accommodate binding of the spike trimer to more than one ACE2 homodimer, and suggests a mechanical contribution of the host receptor towards the large spike conformational changes required for cell fusion. This work presents further structural and functional insights into the role of ACE2 in viral infection that can be exploited for the rational design of effective SARS-CoV-2 therapeutics.Statement of SignificanceAs the host receptor of SARS-CoV-2, ACE2 has been the subject of extensive structural and antibody design efforts in aims to curtail COVID-19 spread. Here, we perform molecular dynamics simulations of the homodimer ACE2 full-length structure to study the dynamics of this protein in the context of the cellular membrane. The simulations evidence exceptional plasticity in the protein structure due to flexible hinge motions in the head-transmembrane domain linker region and helix mobility in the membrane, resulting in a varied ensemble of conformations distinct from the experimental structures. Our findings suggest a dynamical contribution of ACE2 to the spike glycoprotein shedding required for infection, and contribute to the question of stoichiometry of the Spike-ACE2 complex.

scholarly journals Molecular Dynamics Analysis of a Flexible Loop at the Binding Interface of the SARS-CoV-2 Spike Protein Receptor-Binding Domain

2021 ◽  
Author(s):  
Jonathan K. Williams ◽  
Baifan Wang ◽  
Andrew Sam ◽  
Cody L. Hoop ◽  
David A. Case ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Receptor Binding ◽  
Binding Domain ◽  
Conformational Space ◽  
Spike Protein ◽  
Conformational Ensemble ◽  
Receptor Binding Domain ◽  
Loop Modeling ◽  
Binding Interface ◽  
Protein Receptor

AbstractSince the identification of the SARS-CoV-2 virus as the causative agent of the current COVID-19 pandemic, considerable effort has been spent characterizing the interaction between the Spike protein receptor-binding domain (RBD) and the human angiotensin converting enzyme 2 (ACE2) receptor. This has provided a detailed picture of the end point structure of the RBD-ACE2 binding event, but what remains to be elucidated is the conformation and dynamics of the RBD prior to its interaction with ACE2. In this work we utilize molecular dynamics simulations to probe the flexibility and conformational ensemble of the unbound state of the receptor-binding domain from SARS-CoV-2 and SARS-CoV. We have found that the unbound RBD has a localized region of dynamic flexibility in Loop 3 and that mutations identified during the COVID-19 pandemic in Loop 3 do not affect this flexibility. We use a loop-modeling protocol to generate and simulate novel conformations of the CoV2-RBD Loop 3 region that sample conformational space beyond the ACE2 bound crystal structure. This has allowed for the identification of interesting substates of the unbound RBD that are lower energy than the ACE2-bound conformation, and that block key residues along the ACE2 binding interface. These novel unbound substates may represent new targets for therapeutic design.

scholarly journals Effect of RBD (Y453F) mutation in spike glycoprotein of SARS-CoV-2 on neutralizing IgG affinity

2021 ◽  
Author(s):  
Takuma Hayashi ◽  
Nobuo Yaegashi ◽  
Ikuo Konishi
Keyword(s):  
Monoclonal Antibodies ◽  
Structural Analysis ◽  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Virus Disease ◽  
Three Dimensional ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Spike Glycoprotein

AbstractBackgroundInfection with receptor binding domain (RBD) mutant (Y453F) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from farmed minks is known to widely spread among humans.MethodsWe investigated the characteristics of SARS-CoV-2 RBD Y453F mutant using three- dimensional structural analysis. We investigated the effect of the RBD Y453F mutant of SARS-CoV- 2 on neutralizing antibodies in serum derived from Corona virus Disease 2019 (COVID-19) positive patients.ResultsOur studies suggest that virus variants with RBD Y453F mutation partially escaped detection by four neutralizing monoclonal antibodies and neutralizing antibodies in serum.ConclusionsConsequently, raising a concern that infection of SARS-CoV-2 mutants that cause serious symptoms in humans may spread globally.

scholarly journals Structural Analysis of Receptor Binding Domain Mutations in SARS-CoV-2 Variants of Concern that Modulate ACE2 and Antibody Binding

Cell Reports ◽  
2021 ◽  
pp. 110156
Author(s):  
Dhiraj Mannar ◽  
James W. Saville ◽  
Xing Zhu ◽  
Shanti S. Srivastava ◽  
Alison M. Berezuk ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Receptor Binding ◽  
Antibody Binding ◽  
Binding Domain ◽  
Receptor Binding Domain
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