scholarly journals Spherical Neutralizing Aptamer Inhibits SARS-CoV-2 Infection

Author(s):  
Miao Sun ◽  
Siwen Liu ◽  
Ting Song ◽  
Fude Chen ◽  
Jialu Zhang ◽  
...  

<p>New neutralizing agents against SARS-CoV-2 and the associated mutant strains are urgently needed for the treatment and prophylaxis of COVID-19. Herein, we develop a <u>s</u>pherical cocktail <u>n</u>eutralizing <u>a</u>ptamer-gold nano<u>p</u>article (SNAP) to synergistically block the interaction of SARS-CoV-2 receptor-binding domain (RBD) and angiotensin-converting enzyme-2 (ACE2). Taking advantage of the simultaneous recognition of multi-homologous and multi-heterogenous neutralizing aptamers and dimensionally matched nano-scaffolds, the SNAP exhibits increased affinity to the RBD with a dissociation constant value of 5.46 pM and potent neutralization against authentic SARS-CoV-2 with a half-maximal inhibitory concentration of 142.80 aM. Additional benefits include the multi-epitope blocking capability of the aptamer cocktail and the steric hindrance of the nano-scaffold, which further covers the ACE2 binding interfaces and affects the conformational transition of the spike protein. As a result, the SNAP strategy exhibits broad neutralizing activity, almost completely blocking the infection of<a> N501Y</a> and D614G mutant strains. Overall, the SNAP strategy provides a new direction for development of anti-virus infection mechanisms, both to fight the COVID-19 pandemic and serve as a powerful technical reserve for future unknown pandemics.</p>

2021 ◽  
Author(s):  
Miao Sun ◽  
Siwen Liu ◽  
Ting Song ◽  
Fude Chen ◽  
Jialu Zhang ◽  
...  

<p>New neutralizing agents against SARS-CoV-2 and the associated mutant strains are urgently needed for the treatment and prophylaxis of COVID-19. Herein, we develop a <u>s</u>pherical cocktail <u>n</u>eutralizing <u>a</u>ptamer-gold nano<u>p</u>article (SNAP) to synergistically block the interaction of SARS-CoV-2 receptor-binding domain (RBD) and angiotensin-converting enzyme-2 (ACE2). Taking advantage of the simultaneous recognition of multi-homologous and multi-heterogenous neutralizing aptamers and dimensionally matched nano-scaffolds, the SNAP exhibits increased affinity to the RBD with a dissociation constant value of 5.46 pM and potent neutralization against authentic SARS-CoV-2 with a half-maximal inhibitory concentration of 142.80 aM. Additional benefits include the multi-epitope blocking capability of the aptamer cocktail and the steric hindrance of the nano-scaffold, which further covers the ACE2 binding interfaces and affects the conformational transition of the spike protein. As a result, the SNAP strategy exhibits broad neutralizing activity, almost completely blocking the infection of<a> N501Y</a> and D614G mutant strains. Overall, the SNAP strategy provides a new direction for development of anti-virus infection mechanisms, both to fight the COVID-19 pandemic and serve as a powerful technical reserve for future unknown pandemics.</p>


Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1038
Author(s):  
Deborah Giordano ◽  
Luigi De Masi ◽  
Maria Antonia Argenio ◽  
Angelo Facchiano

An outbreak by a new severe acute respiratory syndrome betacoronavirus (SARS-CoV-2) has spread CoronaVirus Disease 2019 (COVID-19) all over the world. Immediately, following studies have confirmed the human Angiotensin-Converting Enzyme 2 (ACE2) as a cellular receptor of viral Spike-Protein (Sp) that mediates the CoV-2 invasion into the pulmonary host cells. Here, we compared the molecular interactions of the viral Sp from previous SARS-CoV-1 of 2002 and SARS-CoV-2 with the host ACE2 protein by in silico analysis of the available experimental structures of Sp-ACE2 complexes. The K417 amino acid residue, located in the region of Sp Receptor-Binding Domain (RBD) of the new coronavirus SARS-CoV-2, showed to have a key role for the binding to the ACE2 N-terminal region. The R426 residue of SARS-CoV-1 Sp-RBD also plays a key role, although by interacting with the central region of the ACE2 sequence. Therefore, our study evidenced peculiarities in the interactions of the two Sp-ACE2 complexes. Our outcomes were consistent with previously reported mutagenesis studies on SARS-CoV-1 and support the idea that a new and different RBD was acquired by SARS-CoV-2. These results have interesting implications and suggest further investigations.


2020 ◽  
Author(s):  
Saroj Kumar Panda ◽  
Parth Sarthi Sen Gupta ◽  
Satyaranjan Biswal ◽  
Abhik Kumar Ray ◽  
Malay Kumar Rana

<p>SARS-CoV-2, a novel coronavirus causing overwhelming death and infection worldwide, has emerged as a pandemic. Compared to its predecessor SARS-CoV, SARS-CoV-2 is more infective for being highly contagious and exhibiting tighter binding with host angiotensin-converting enzyme 2 (hACE-2). The entry of the virus into host cells is mediated by the interaction of its spike protein with hACE-2. Thus, a peptide that has a resemblance to hACE-2 but can overpower the spike protein-hACE-2 interaction will be a potential therapeutic to contain this virus. The non-interacting residues in the receptor-binding domain of hACE-2 have been mutated to generate a library of 136 new peptides. Out of this library, docking and virtual screening discover seven peptides that can exert a stronger interaction with the spike protein than hACE-2. A peptide derived from simultaneous mutation of all the non-interacting residues of hACE-2 yields two-fold stronger interaction than hACE-2 and thus turns out here to be the best peptide-inhibitor of the novel coronavirus. The binding of the spike protein and the best peptide-inhibitor with hACE-2 is explored further by molecular dynamics, free energy, and principal component analysis to demonstrate its efficacy. Further, the inhibition assay study with the best peptide inhibitor is in progress. </p>


2021 ◽  
Author(s):  
Vince St. Dollente Mesias ◽  
Hongni Zhu ◽  
Xiao Tang ◽  
Xin Dai ◽  
Yusong Guo ◽  
...  

The infection of coronavirus initiates with the binding between its spike protein receptor binding domain (RBD) and a human cellular receptor called angiotensin-converting enzyme 2 (ACE2). Here, we construct truncated...


mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
James R. Byrnes ◽  
Xin X. Zhou ◽  
Irene Lui ◽  
Susanna K. Elledge ◽  
Jeff E. Glasgow ◽  
...  

ABSTRACT As severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread around the world, there is an urgent need for new assay formats to characterize the humoral response to infection. Here, we present an efficient, competitive serological assay that can simultaneously determine an individual’s seroreactivity against the SARS-CoV-2 Spike protein and determine the proportion of anti-Spike antibodies that block interaction with the human angiotensin-converting enzyme 2 (ACE2) required for viral entry. In this approach based on the use of enzyme-linked immunosorbent assays (ELISA), we present natively folded viral Spike protein receptor-binding domain (RBD)-containing antigens via avidin-biotin interactions. Sera are then competed with soluble ACE2-Fc, or with a higher-affinity variant thereof, to determine the proportion of ACE2 blocking anti-RBD antibodies. Assessment of sera from 144 SARS-CoV-2 patients ultimately revealed that a remarkably consistent and high proportion of antibodies in the anti-RBD pool targeted the epitope responsible for ACE2 engagement (83% ± 11%; 50% to 107% signal inhibition in our largest cohort), further underscoring the importance of tailoring vaccines to promote the development of such antibodies. IMPORTANCE With the emergence and continued spread of the SARS-CoV-2 virus, and of the associated disease, coronavirus disease 2019 (COVID-19), there is an urgent need for improved understanding of how the body mounts an immune response to the virus. Here, we developed a competitive SARS-CoV-2 serological assay that can simultaneously determine whether an individual has developed antibodies against the SARS-CoV-2 Spike protein receptor-binding domain (RBD) and measure the proportion of these antibodies that block interaction with the human angiotensin-converting enzyme 2 (ACE2) required for viral entry. Using this assay and 144 SARS-CoV-2 patient serum samples, we found that a majority of anti-RBD antibodies compete for ACE2 binding. These results not only highlight the need to design vaccines to generate such blocking antibodies but also demonstrate the utility of this assay to rapidly screen patient sera for potentially neutralizing antibodies.


2020 ◽  
Author(s):  
Edward P. Gniffke ◽  
Whitney E. Harrington ◽  
Nicholas Dambrauskas ◽  
Yonghou Jiang ◽  
Olesya Trakhimets ◽  
...  

AbstractHigh throughput serological tests that can establish the presence and functional activity of anti-SARS-COV2 antibodies are urgently needed. Here we present microsphere-based Flow Cytometry assays that quantify both anti-spike IgGs in plasma, and the ability of plasma to inhibit the binding of spike protein to angiotensin converting enzyme 2 (ACE2). First, we detected anti-spike-trimer IgGs in 22/24 and anti-spike-receptor-binding-domain (RBD) IgGs in 21/24 COVID+ subjects at a median of 36 (range 14-73) days following documented SARS-CoV-2 RNA (+) secretions. Next, we find that plasma from all 22/24 subjects with anti-trimer IgGs inhibited ACE2-trimer binding to a greater degree than controls, and that the degree of inhibition correlated with anti-trimer IgG levels. Depletion of trimer-reactive Igs from plasma reduced ACE2-trimer inhibitory capacity to a greater degree than depletion of RBD-reactive Igs, suggesting that inhibitory antibodies act by binding both within and outside of the RBD. Amongst the 24 subjects, presence of fever was associated with higher levels of anti-trimer IgG and inhibition of binding to human ACE2. This inhibition assay may be broadly useful to quantify the functional antibody response of recovered COVID19 patients or vaccine recipients in a cell-free assay system.


2021 ◽  
Vol 14 (10) ◽  
pp. 954
Author(s):  
Paolo Coghi ◽  
Li Jun Yang ◽  
Jerome P. L. Ng ◽  
Richard K. Haynes ◽  
Maurizio Memo ◽  
...  

Host cell invasion by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is mediated by the interaction of the viral spike protein (S) with human angiotensin-converting enzyme 2 (ACE2) through the receptor-binding domain (RBD). In this work, computational and experimental techniques were combined to screen antimalarial compounds from different chemical classes, with the aim of identifying small molecules interfering with the RBD-ACE2 interaction and, consequently, with cell invasion. Docking studies showed that the compounds interfere with the same region of the RBD, but different interaction patterns were noted for ACE2. Virtual screening indicated pyronaridine as the most promising RBD and ACE2 ligand, and molecular dynamics simulations confirmed the stability of the predicted complex with the RBD. Bio-layer interferometry showed that artemisone and methylene blue have a strong binding affinity for RBD (KD = 0.363 and 0.226 μM). Pyronaridine also binds RBD and ACE2 in vitro (KD = 56.8 and 51.3 μM). Overall, these three compounds inhibit the binding of RBD to ACE2 in the μM range, supporting the in silico data.


2021 ◽  
Author(s):  
Kazuki Akisawa ◽  
Ryo Hatano ◽  
Koji Okuwaki ◽  
Shun Kitahara ◽  
Yusuke Tachino ◽  
...  

The spike protein plays an important role in the infection of SARS-CoV-2 to human cells, and the binding affinity of receptor binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2) is of special interest. In this report, we present a series of interaction analyses for the RBD - ACE2 complex (PDB ID: 6M0J) and mutated complexes of UK (B.1.1.7 lineage), South Africa (B1.3.51) and Brazil (B1.1.248) types, based on the fragment molecular orbital (FMO) calculations. The effects of mutations are investigated in terms of inter-fragment interaction energies (IFIEs), indicating the higher affinities of RBD variants with ACE2.


2021 ◽  
Author(s):  
Laura A. VanBlargan ◽  
Lucas J. Adams ◽  
Zhuoming Liu ◽  
Rita E. Chen ◽  
Pavlo Gilchuk ◽  
...  

SUMMARYWith the emergence of SARS-CoV-2 variants with increased transmissibility and potential resistance, antibodies and vaccines with broadly inhibitory activity are needed. Here we developed a panel of neutralizing anti-SARS-CoV-2 mAbs that bind the receptor binding domain of the spike protein at distinct epitopes and block virus attachment to cells and its receptor, human angiotensin converting enzyme-2 (hACE2). While several potently neutralizing mAbs protected K18-hACE2 transgenic mice against infection caused by historical SARS-CoV-2 strains, others induced escape variantsin vivoand lost activity against emerging strains. We identified one mAb, SARS2-38, that potently neutralizes all SARS-CoV-2 variants of concern tested and protects mice against challenge by multiple SARS-CoV-2 strains. Structural analysis showed that SARS2-38 engages a conserved epitope proximal to the receptor binding motif. Thus, treatment with or induction of inhibitory antibodies that bind conserved spike epitopes may limit the loss of potency of therapies or vaccines against emerging SARS-CoV-2 variants.


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