scholarly journals Structural Comparison of the SARS CoV 2 Spike Protein Relative to Other Human-Infecting Coronaviruses

2021 ◽  
Vol 7 ◽  
Author(s):  
Marni E. Cueno ◽  
Kenichi Imai
Keyword(s):  
Spike Protein ◽  
Structural Comparison ◽  
Model Quality ◽  
Structural Orientation ◽  
Contact Mapping ◽  
Phylogenetic Cluster ◽  
Structural Conformation ◽  
Protein Model ◽  
Degree Of Similarity ◽  
Spike Proteins

Coronaviruses (CoV) are enveloped positive-stranded RNA viruses and, historically, there are seven known human-infecting CoVs with varying degrees of virulence. CoV attachment to the host is the first step of viral pathogenesis and mainly relies on the spike glycoprotein located on the viral surface. Among the human-infecting CoVs, only the infection of SARS CoV 2 (SARS2) among humans resulted to a pandemic which would suggest that the protein structural conformation of SARS2 spike protein is distinct as compared to other human-infecting CoVs. Surprisingly, the possible differences and similarities in the protein structural conformation between the various human-infecting CoV spike proteins have not been fully elucidated. In this study, we utilized a computational approach to generate models and analyze the seven human-infecting CoV spike proteins, namely: HCoV 229E, HCoV OC43, HCoV NL63, HCoV HKU1, SARS CoV, MERS CoV, and SARS2. Model quality assessment of all CoV models generated, structural superimposition of the whole protein model and selected S1 domains (S1-CTD and S1-NTD), and structural comparison based on RMSD values, Tm scores, and contact mapping were all performed. We found that the structural orientation of S1-CTD is a potential structural feature associated to both the CoV phylogenetic cluster and lineage. Moreover, we observed that spike models in the same phylogenetic cluster or lineage could potentially have similar protein structure. Additionally, we established that there are potentially three distinct S1-CTD orientation (Pattern I, Pattern II, Pattern III) among the human-infecting CoVs. Furthermore, we postulate that human-infecting CoVs in the same phylogenetic cluster may have similar S1-CTD and S1-NTD structural orientation. Taken together, we propose that the SARS2 spike S1-CTD follows a Pattern III orientation which has a higher degree of similarity with SARS1 and some degree of similarity with both OC43 and HKU1 which coincidentally are in the same phylogenetic cluster and lineage, whereas, the SARS2 spike S1-NTD has some degree of similarity among human-infecting CoVs that are either in the same phylogenetic cluster or lineage.

scholarly journals Structural Insights on the SARS-CoV-2 Variants of Concern Spike Glycoprotein: A Computational Study With Possible Clinical Implications

2021 ◽  
Vol 12 ◽  
Author(s):  
Marni E. Cueno ◽  
Kenichi Imai
Keyword(s):  
Computational Study ◽  
Structural Similarity ◽  
Cross Reactivity ◽  
Spike Protein ◽  
Structural Comparison ◽  
Model Quality ◽  
Contact Mapping ◽  
Phylogenetic Cluster ◽  
Conformational Epitopes ◽  
Structural Differences

Coronavirus disease 2019 (COVID-19) pandemic has been attributed to SARS-CoV-2 (SARS2) and, consequently, SARS2 has evolved into multiple SARS2 variants driving subsequent waves of infections. In particular, variants of concern (VOC) were identified to have both increased transmissibility and virulence ascribable to mutational changes occurring within the spike protein resulting to modifications in the protein structural orientation which in-turn may affect viral pathogenesis. However, this was never fully elucidated. Here, we generated spike models of endemic HCoVs (HCoV 229E, HCoV OC43, HCoV NL63, HCoV HKU1, SARS CoV, MERS CoV), original SARS2, and VOC (alpha, beta, gamma, delta). Model quality check, structural superimposition, and structural comparison based on RMSD values, TM scores, and contact mapping were all performed. We found that: 1) structural comparison between the original SARS2 and VOC whole spike protein model have minor structural differences (TM > 0.98); 2) the whole VOC spike models putatively have higher structural similarity (TM > 0.70) to spike models from endemic HCoVs coming from the same phylogenetic cluster; 3) original SARS2 S1-CTD and S1-NTD models are structurally comparable to VOC S1-CTD (TM = 1.0) and S1-NTD (TM > 0.96); and 4) endemic HCoV S1-CTD and S1-NTD models are structurally comparable to VOC S1-CTD (TM > 0.70) and S1-NTD (TM > 0.70) models belonging to the same phylogenetic cluster. Overall, we propose that structural similarities (possibly ascribable to similar conformational epitopes) may help determine immune cross-reactivity, whereas, structural differences (possibly associated with varying conformational epitopes) may lead to viral infection (either reinfection or breakthrough infection).

scholarly journals Reoptimized UNRES Potential for Protein Model Quality Assessment

Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 601 ◽  
Author(s):  
Eshel Faraggi ◽  
Pawel Krupa ◽  
Magdalena Mozolewska ◽  
Adam Liwo ◽  
Andrzej Kloczkowski
Keyword(s):  
Protein Structure ◽  
Coarse Grained ◽  
Poor Correlation ◽  
Native Structure ◽  
Feed Forward Neural Network ◽  
Model Quality ◽  
Protein Model ◽  
Protein Model Quality Assessment ◽  
Dynamics Simulations ◽  
Degree Of Similarity

Ranking protein structure models is an elusive problem in bioinformatics. These models are evaluated on both the degree of similarity to the native structure and the folding pathway. Here, we simulated the use of the coarse-grained UNited RESidue (UNRES) force field as a tool to choose the best protein structure models for a given protein sequence among a pool of candidate models, using server data from the CASP11 experiment. Because the original UNRES was optimized for Molecular Dynamics simulations, we reoptimized UNRES using a deep feed-forward neural network, and we show that introducing additional descriptive features can produce better results. Overall, we found that the reoptimized UNRES performs better in selecting the best structures and tracking protein unwinding from its native state. We also found a relatively poor correlation between UNRES values and the model’s Template Modeling Score (TMS). This is remedied by reoptimization. We discuss some cases where our reoptimization procedure is useful. The reoptimized version of UNRES (OUNRES) is available at http://mamiris.com and http://www.unres.pl.

scholarly journals Unraveling the stability landscape of mutations in the SARS-CoV-2 receptor-binding domain

2020 ◽  
Author(s):  
Mohamed Raef Smaoui ◽  
Hamdi Yahyaoui
Keyword(s):  
Receptor Binding ◽  
Single Point ◽  
Protein Structures ◽  
Point Mutations ◽  
Binding Domain ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Point Mutant ◽  
The Stability ◽  
Spike Proteins

Abstract The interaction between the receptor-binding domain of the SARS-CoV-2 spike glycoprotein and the ACE2 enzyme is believed to be the entry point of the virus into various cells in the body, including the lungs, heart, liver, and kidneys. The current focus of several therapeutic design efforts explore attempts at affecting the binding interaction between the two proteins to limit the activity of the virus and disease progression. In this work, we analyze the stability of the spike protein under all possible single-point mutations in the receptor-binding domain and computationally explore mutations that can affect the binding with the ACE2 enzyme. We unravel the mutation landscape of the receptor region and assess the toxicity potential of single and multi-point mutations, generating insights for future vaccine efforts on potential mutations that might further stabilize the spike protein and increase its infectivity. We developed a tool, called SpikeMutator, to construct full atomic protein structures of the mutant spike proteins and shared a database of 3,800 single-point mutant structures. We analyzed the recent 65,000 reported spike sequences across the globe and observed the emergence of stable multi-point mutant structures. Using the landscape, we searched through 7.5 million possible 2-point mutation combinations and report that the (R355D K424E) mutation produces one of the strongest spike proteins that therapeutic efforts should investigate for the sake of developing an effective vaccine.

scholarly journals Developing a Fully Glycosylated Full-Length SARS-CoV-2 Spike Protein Model in a Viral Membrane

2020 ◽  
Vol 124 (33) ◽  
pp. 7128-7137 ◽  
Author(s):  
Hyeonuk Woo ◽  
Sang-Jun Park ◽  
Yeol Kyo Choi ◽  
Taeyong Park ◽  
Maham Tanveer ◽  
...  
Keyword(s):  
Full Length ◽  
Spike Protein ◽  
Viral Membrane ◽  
Protein Model

scholarly journals Trimeric SARS-CoV-2 Spike Proteins Produced from CHO Cells in Bioreactors Are High-Quality Antigens

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1539
Author(s):  
Paco Pino ◽  
Joeri Kint ◽  
Divor Kiseljak ◽  
Valentina Agnolon ◽  
Giampietro Corradin ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Neutralizing Antibodies ◽  
Good Manufacturing Practice ◽  
Spike Protein ◽  
High Quality ◽  
Virus Surface ◽  
Corona Virus ◽  
Global Demand ◽  
Diagnostic Sensitivity And Specificity ◽  
Spike Proteins

The spike protein of the pandemic human corona virus is essential for its entry into human cells. In fact, most neutralizing antibodies against Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) are directed against the Virus-surface exposed spike protein, making it the antigen of choice for use in vaccines and diagnostic tests. In the current pandemic context, global demand for spike proteins has rapidly increased and could exceed hundreds of grams to kilograms annually. Coronavirus spikes are large heavily glycosylated homo-trimeric complexes, with inherent instability. The poor manufacturability now threatens the availability of these proteins for vaccines and diagnostic tests. Here, we outline scalable, Good Manufacturing Practice (GMP) compliant, and chemically defined processes for the production of two cell-secreted stabilized forms of the trimeric spike proteins (Wuhan and D614G variant). The processes are chemically defined and based on clonal suspension-CHO cell populations and on protein purification via a two-step scalable downstream process. The trimeric conformation was confirmed using electron microscopy and HPLC analysis. Binding to susceptible cells was shown using a virus-inhibition assay. The diagnostic sensitivity and specificity for detection of serum SARS-CoV-2-specific-immunoglobulin molecules was found to exceed that of spike fragments (Spike subunit-1, S1 and Receptor Binding Domain, RBD). The process described here will enable production of sufficient high-quality trimeric spike protein to meet the global demand for SARS-CoV-2 diagnostic tests and potentially vaccines.

scholarly journals High-Potency Polypeptide-based Interference for Coronavirus Spike Glycoproteins

2021 ◽  
Author(s):  
Qinghua Wang ◽  
Jianpeng Ma ◽  
Adam Acevedo
Keyword(s):  
Amino Acid Sequence Identity ◽  
Natural Infection ◽  
Viral Proteins ◽  
Spike Protein ◽  
High Potency ◽  
Viral Pathogens ◽  
Native Sequence ◽  
Virion Envelope ◽  
Novel Concept ◽  
Spike Proteins

Abstract The world is experiencing an unprecedented coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 spike protein-based vaccines are currently the main preventive agent to fight against the virus. However, several variants with extensive mutations in SARS-CoV-2 spike proteins have emerged. Some of these variants exhibited increased replication, higher transmission and virulence, and were partially resistant to antibody neutralization from natural infection or vaccination. With over 130 million confirmed cases and widespread vaccination around the globe, the emergence of new escape SARS-CoV-2 variants could be accelerated. New therapeutics insensitive to mutations are thus urgently needed. Here we have developed an inhibitor based on SARS-CoV-2 spike protein that potently reduced pseudovirus infectivity by limiting the level of SARS-CoV-2 spike proteins on virion envelope. Most importantly, the inhibitor was equally effective against other coronavirus spike proteins that shared as low as 35% amino-acid sequence identity, underscoring its extreme tolerance to mutations. The small-sized inhibitor would also allow simple delivery by, for instance, nasal spray. We expect the inhibitor reported here to be an invaluable aid to help end COVID-19 pandemic. Furthermore, the use of a partial native sequence or its homologues to interfere with the functions of the native protein represents a novel concept for targeting other viral proteins in combating against important viral pathogens.

scholarly journals Estimating local protein model quality: prospects for molecular replacement

2020 ◽  
Vol 76 (3) ◽  
pp. 285-290
Author(s):  
Björn Wallner
Keyword(s):  
Error Estimates ◽  
Added Value ◽  
Local Error ◽  
Molecular Replacement ◽  
Model Quality ◽  
Data Set ◽  
Protein Model ◽  
Protein Models ◽  
Local Protein

Model quality assessment programs estimate the quality of protein models and can be used to estimate local error in protein models. ProQ3D is the most recent and most accurate version of our software. Here, it is demonstrated that it is possible to use local error estimates to substantially increase the quality of the models for molecular replacement (MR). Adjusting the B factors using ProQ3D improved the log-likelihood gain (LLG) score by over 50% on average, resulting in significantly more successful models in MR compared with not using error estimates. On a data set of 431 homology models to address difficult MR targets, models with error estimates from ProQ3D received an LLG of >50 for almost half of the models 209/431 (48.5%), compared with 175/431 (40.6%) for the previous version, ProQ2, and only 74/431 (17.2%) for models with no error estimates, clearly demonstrating the added value of using error estimates to enable MR for more targets. ProQ3D is available from http://proq3.bioinfo.se/ both as a server and as a standalone download.

scholarly journals Harnessing the Sars-cov-2 Spike Protein Binding Affinity to Ace2 Receptor Through Narcotinic Compounds Combined With Adjuvants: an in Silico Insight

2021 ◽  
Author(s):  
Saeedeh Mohammadi ◽  
Esmail Doustkhah ◽  
Nader Sakhaee ◽  
Ayoub Esmailpour ◽  
Mohammad Esmailpour
Keyword(s):  
Binding Affinity ◽  
In Silico ◽  
Muramyl Dipeptide ◽  
Docking Studies ◽  
Spike Protein ◽  
Binding Affinities ◽  
Narcotic Analgesics ◽  
S Protein ◽  
Suitable Combination ◽  
Spike Proteins

Abstract Protein products of SARS-CoV-2 spike (S) coding gene sequence, were all analyzed and compared to other SARS-CoV S proteins to elucidate structural similarities of spike proteins. A homology modeling of SARS-CoV-2 S protein was obtained and used in molecular docking studies to find binding affinities of spike protein for angiotensin-converting enzyme 2 (ACE2). The two most important binding sites of S protein, namely, RBD and CTD, critically responsible for binding interactions, were identified. Finally, binding affinity of RBD and CTD domains of S protein with narcotic analgesics are studied. Moreover, interactions of ACE2 receptor- S protein with narcotic compounds when mixed with small molecule adjuvants to improve the immune response and increase the efficacy of potential vaccines, were taken into consideration. In-silico results suggest that the combination of narcotine hemiacetal with mannide monooleate shows a stronger binding affinity with CTD, while carprofen-muramyl dipeptide and squalene have stronger binding affinities for the RBD portion of S protein. Thus, a suitable combination of these narcotic is proposed to yield potent site-blocking efficacy for ACE2 receptor against SARS-CoV-2 spike proteins.

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