scholarly journals Deducing the N- and O-glycosylation profile of the spike protein of novel coronavirus SARS-CoV-2

Glycobiology ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 981-988 ◽  
Author(s):  
Asif Shajahan ◽  
Nitin T Supekar ◽  
Anne S Gleinich ◽  
Parastoo Azadi
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Critical Role ◽  
Spike Protein ◽  
Protein Subunit ◽  
Binding Studies ◽  
Viral Attachment ◽  
Protein Subunits ◽  
Glycosylation Profile ◽  
Viral Binding ◽  
Novel Coronavirus

Abstract The current emergence of the novel coronavirus pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) demands the development of new therapeutic strategies to prevent rapid progress of mortalities. The coronavirus spike (S) protein, which facilitates viral attachment, entry and membrane fusion is heavily glycosylated and plays a critical role in the elicitation of the host immune response. The spike protein is comprised of two protein subunits (S1 and S2), which together possess 22 potential N-glycosylation sites. Herein, we report the glycosylation mapping on spike protein subunits S1 and S2 expressed on human cells through high-resolution mass spectrometry. We have characterized the quantitative N-glycosylation profile on spike protein and interestingly, observed unexpected O-glycosylation modifications on the receptor-binding domain of spike protein subunit S1. Even though O-glycosylation has been predicted on the spike protein of SARS-CoV-2, this is the first report of experimental data for both the site of O-glycosylation and identity of the O-glycans attached on the subunit S1. Our data on the N- and O-glycosylation are strengthened by extensive manual interpretation of each glycopeptide spectra in addition to using bioinformatics tools to confirm the complexity of glycosylation in the spike protein. The elucidation of the glycan repertoire on the spike protein provides insights into the viral binding studies and more importantly, propels research toward the development of a suitable vaccine candidate.

scholarly journals Deducing the N- and O- glycosylation profile of the spike protein of novel coronavirus SARS-CoV-2

2020 ◽  
Author(s):  
Asif Shajahan ◽  
Nitin T. Supekar ◽  
Anne S. Gleinich ◽  
Parastoo Azadi
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Critical Role ◽  
Spike Protein ◽  
Protein Subunit ◽  
Binding Studies ◽  
Viral Attachment ◽  
Protein Subunits ◽  
Glycosylation Profile ◽  
Viral Binding ◽  
Novel Coronavirus

AbstractThe current emergence of the novel coronavirus pandemic caused by SARS-CoV-2 demands the development of new therapeutic strategies to prevent rapid progress of mortalities. The coronavirus spike (S) protein, which facilitates viral attachment, entry and membrane fusion is heavily glycosylated and plays a critical role in the elicitation of the host immune response. The spike protein is comprised of two protein subunits (S1 and S2), which together possess 22 potential N-glycosylation sites. Herein, we report the glycosylation mapping on spike protein subunits S1 and S2 expressed on human cells through high resolution mass spectrometry. We have characterized the quantitative N-glycosylation profile on spike protein and interestingly, observed unexpected O-glycosylation modifications on the receptor binding domain (RBD) of spike protein subunit S1. Even though O-glycosylation has been predicted on the spike protein of SARS-CoV-2, this is the first report of experimental data for both the site of O-glycosylation and identity of the O-glycans attached on the subunit S1. Our data on the N- and O-glycosylation is strengthened by extensive manual interpretation of each glycopeptide spectra in addition to using bioinformatics tools to confirm the complexity of glycosylation in the spike protein. The elucidation of the glycan repertoire on the spike protein provides insights into the viral binding studies and more importantly, propels research towards the development of a suitable vaccine candidate.

scholarly journals Peptide Scanning of SARS-CoV and SARS-CoV-2 Spike Protein Subunit 1 Reveals Potential Additional Receptor Binding Sites

2021 ◽  
Author(s):  
Weilin Lin ◽  
Jannatul Rafeya ◽  
Vanessa Roschewitz ◽  
David Smith ◽  
Adrian Keller ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Binding Sites ◽  
Neutralizing Antibodies ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Spike Protein ◽  
Loss Of Function ◽  
Protein Subunit ◽  
Viral Attachment ◽  
High Affinity

The binding of SARS-CoV and SARS-CoV-2 to the ACE2 receptor on human cells is mediated by the spike protein subunit 1 (S1) on the virus surfaces, while the receptor binding domains (RBDs) of S1 are the major determinants for the interaction with ACE2 and dominant targets of neutralizing antibodies. However, at the virus-host interface, additional biomolecular interactions, although being relatively weak in affinity and low in specificity, could also contribute to viral attachment and play important roles in gain- or loss-of-function mutations. In this work, we performed a peptide scanning of the S1 domains of SARS-CoV and SARS-CoV-2 by synthesizing 972 16-mer native and mutated peptide fragments using a high throughput in situ array synthesis technology. By probing the array using fluorescently labelled ACE2, a number of previously unknown potential receptor binding sites of S1 have been revealed. 20 peptides were synthesized using solid phase peptide synthesis, in order to validate and quantify their binding to ACE2. Four ACE2-binding peptides were selected, to investigate whether they can be assembled through a biotinylated peptide/neutravidin system to achieve high affinity to ACE2. A number of constructs exhibited high affinity to ACE2 with Kd values of pM to low nM.

scholarly journals Mucin-type O-glycosylation Landscapes of SARS-CoV-2 Spike Proteins

2020 ◽  
Author(s):  
Yong Zhang ◽  
Wanjun Zhao ◽  
Yonghong Mao ◽  
Yaohui Chen ◽  
Jingqiang Zhu ◽  
...  
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Targeted Drugs ◽  
Cell Type ◽  
Glycosylation Pattern ◽  
Site Specific ◽  
S Protein ◽  
Viral Attachment ◽  
Viral Binding ◽  
Pngase F ◽  
S Proteins

ABSTRACTThe densely glycosylated spike (S) proteins that are highly exposed on the surface of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) facilitate viral attachment, entry, and membrane fusion. We have previously reported all the 22 N-glycosites and site-specific N-glycans in the S protein protomer. Herein, we report the comprehensive and precise site-specific O-glycosylation landscapes of SARS-CoV-2 S proteins, which were characterized using high-resolution mass spectrometry. Following digestion using trypsin and trypsin/Glu-C, and de-N-glycosylation using PNGase F, we determined the mucin-type (GalNAc-type) O-glycosylation pattern of S proteins, including unambiguous O-glycosites and the 6 most common O-glycans occupying them, via Byonic identification and manual validation. Finally, 43 O-glycosites were identified in the insect cell-expressed S protein. Most glycosites were modified by non-sialylated O-glycans such as HexNAc(1) and HexNAc(1)Hex(1). In contrast, 30 O-glycosites were identified in the human cell-expressed S protein S1 subunit. Most glycosites were modified by sialylated O-glycans such as HexNAc(1)Hex(1)NeuAc(1) and HexNAc(1)Hex(1)NeuAc(2). Our results are the first to reveal that the SARS-CoV-2 S protein is a mucin-type glycoprotein; clustered O-glycans often occur in the N- and the C-termini of the S protein, and the O-glycosite and O-glycan compositions vary with the host cell type. These site-specific O-glycosylation landscapes of the SARS-CoV-2 S protein are expected to provide novel insights into the viral binding mechanism and present a strategy for the development of vaccines and targeted drugs.

scholarly journals O-Glycosylation Landscapes of SARS-CoV-2 Spike Proteins

2021 ◽  
Vol 9 ◽  
Author(s):  
Yong Zhang ◽  
Wanjun Zhao ◽  
Yonghong Mao ◽  
Yaohui Chen ◽  
Shanshan Zheng ◽  
...  
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Collision Induced Dissociation ◽  
Energy Collision ◽  
Cell Type ◽  
Glycosylation Pattern ◽  
S Protein ◽  
Viral Attachment ◽  
Viral Binding ◽  
Pngase F ◽  
S Proteins

The densely glycosylated spike (S) proteins that are highly exposed on the surface of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) facilitate viral attachment, entry, and membrane fusion. We have previously reported all the 22 N-glycosites and site-specific N-glycans in the S protein protomer. Herein, we report the O-glycosylation landscapes of SARS-CoV-2 S proteins, which were characterized through high-resolution mass spectrometry. Following digestion with trypsin and trypsin/Glu-C, and de-N-glycosylation using PNGase F, we determined the GalNAc-type O-glycosylation pattern of S proteins, including O-glycosites and the six most common O-glycans occupying them, via Byonic identification and manual validation. Finally, 255 intact O-glycopeptides composed of 50 peptides sequences and 43 O-glycosites were discovered by higher energy collision-induced dissociation (HCD), and three O-glycosites were confidently identified by electron transfer/higher energy collision-induced dissociation (EThcD) in the insect cell-expressed S protein. Most glycosites were modified by non-sialylated O-glycans such as HexNAc(1) and HexNAc(1)Hex (1). In contrast, in the human cell-expressed S protein S1 subunit, 407 intact O-glycopeptides composed of 34 peptides sequences and 30 O-glycosites were discovered by HCD, and 11 O-glycosites were unambiguously assigned by EThcD. However, the measurement of O-glycosylation occupancy hasn’t been made. Most glycosites were modified by sialylated O-glycans such as HexNAc(1)Hex (1)NeuAc (1) and HexNAc(1)Hex (1)NeuAc (2). Our results reveal that the SARS-CoV-2 S protein is an O-glycoprotein; the O-glycosites and O-glycan compositions vary with the host cell type. These comprehensive O-glycosylation landscapes of the S protein are expected to provide novel insights into the viral binding mechanism and present a strategy for the development of vaccines and targeted drugs.

scholarly journals Exploring Conformational Transition of 2019 Novel Coronavirus Spike Glycoprotein Between Its Closed and Open States Using Molecular Dynamics Simulations

2020 ◽  
Author(s):  
Mert Gur ◽  
Elhan Taka ◽  
Sema Zeynep Yilmaz ◽  
Ceren Kilinc ◽  
Umut Aktas ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Host Cell ◽  
Crystal Structures ◽  
Critical Role ◽  
Minimum Energy ◽  
Md Simulations ◽  
Host Cells ◽  
Spike Protein ◽  
Novel Coronavirus ◽  
Open States

ABSTRACTSince its first recorded appearance in December 2019, a novel coronavirus (SARS-CoV-2) causing the disease COVID-19 has resulted in more than 2,000,000 infections and 128,000 deaths. Currently there is no proven treatment for COVID-19 and there is an urgent need for the development of vaccines and therapeutics. Coronavirus spike glycoproteins play a critical role in coronavirus entry into the host cells, as they provide host cell recognition and membrane fusion between virus and host cell. Thus, they emerged as popular and promising drug targets. Crystal structures of spike protein in its closed and open states were resolved very recently in March 2020. These structures comprise 77% of the sequence and provide almost the complete protein structure. Based on down and up positions of receptor binding domain (RBD), spike protein can be in a receptor inaccessible closed or receptor accessible open state, respectively. Starting from closed and open state crystal structures, and also 16 intermediate conformations, an extensive set of all-atom molecular dynamics (MD) simulations in the presence of explicit water and ions were performed. Simulations show that in its down position, RBD has significantly lower mobility compared to its up position; probably caused by the 6 interdomain salt bridges of RBD in down position compared to 3 in up position. Free energy landscapes based on MD simulations revealed a semi-open state located between closed and open states. Minimum energy pathway between down and up positions comprised a gradual salt bridge switching mechanism. Furthermore, although significantly lower than open state, ACE2 binding surface of RBD contained a partial solvent accessibility in its closed state.

scholarly journals Ultrafiltration Method for Plasma Protein Binding Studies and Its Limitations

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 382
Author(s):  
Camelia-Maria Toma ◽  
Silvia Imre ◽  
Camil-Eugen Vari ◽  
Daniela-Lucia Muntean ◽  
Amelia Tero-Vescan
Keyword(s):  
Protein Binding ◽  
Plasma Protein Binding ◽  
Plasma Protein ◽  
Specific Binding ◽  
Critical Role ◽  
Volume Ratio ◽  
Binding Studies ◽  
Experimental Conditions ◽  
Key Aspects

Plasma protein binding plays a critical role in drug therapy, being a key part in the characterization of any compound. Among other methods, this process is largely studied by ultrafiltration based on its advantages. However, the method also has some limitations that could negatively influence the experimental results. The aim of this study was to underline key aspects regarding the limitations of the ultrafiltration method, and the potential ways to overcome them. The main limitations are given by the non-specific binding of the substances, the effect of the volume ratio obtained, and the need of a rigorous control of the experimental conditions, especially pH and temperature. This review presents a variety of methods that can hypothetically reduce the limitations, and concludes that ultrafiltration remains a reliable method for the study of protein binding. However, the methodology of the study should be carefully chosen.

scholarly journals Blocking Effect of Demethylzeylasteral on the Interaction between Human ACE2 Protein and SARS-CoV-2 RBD Protein Discovered Using SPR Technology

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 57
Author(s):  
Zhi-Ling Zhu ◽  
Xiao-Dan Qiu ◽  
Shuo Wu ◽  
Yi-Tong Liu ◽  
Ting Zhao ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Blocking Effect ◽  
Spike Protein ◽  
Binding Affinities ◽  
The Novel ◽  
Converting Enzyme ◽  
Primary Method ◽  
Angiotensin Converting Enzyme 2 ◽  
Novel Coronavirus ◽  
Effective Drugs

The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019, and there is no sign that the epidemic is abating. Targeting the interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptor is a promising therapeutic strategy. In this study, surface plasmon resonance (SPR) was used as the primary method to screen a library of 960 compounds. A compound 02B05 (demethylzeylasteral, CAS number: 107316-88-1) that had high affinities for S-RBD and ACE2 was discovered, and binding affinities (KD, μM) of 02B05-ACE2 and 02B05-S-RBD were 1.736 and 1.039 μM, respectively. The results of a competition experiment showed that 02B05 could effectively block the binding of S-RBD to ACE2 protein. Furthermore, pseudovirus infection assay revealed that 02B05 could inhibit entry of SARS-CoV-2 pseudovirus into 293T cells to a certain extent at nontoxic concentration. The compoundobtained in this study serve as references for the design of drugs which have potential in the treatment of COVID-19 and can thus accelerate the process of developing effective drugs to treat SARS-CoV-2 infections.

scholarly journals ACE2 Nascence, trafficking, and SARS-CoV-2 pathogenesis: the saga continues

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Sally Badawi ◽  
Bassam R. Ali
Keyword(s):  
Cell Surface ◽  
Angiotensin Converting Enzyme ◽  
The Novel ◽  
Converting Enzyme ◽  
Post Translational Modifications ◽  
Angiotensin Converting Enzyme 2 ◽  
Viral Attachment ◽  
Novel Coronavirus ◽  
Effective Medication ◽  
Potential Use

AbstractWith the emergence of the novel coronavirus SARS-CoV-2 since December 2019, more than 65 million cases have been reported worldwide. This virus has shown high infectivity and severe symptoms in some cases, leading to over 1.5 million deaths globally. Despite the collaborative and concerted research efforts that have been made, no effective medication for COVID-19 (coronavirus disease-2019) is currently available. SARS-CoV-2 uses the angiotensin-converting enzyme 2 (ACE2) as an initial mediator for viral attachment and host cell invasion. ACE2 is widely distributed in the human tissues including the cell surface of lung cells which represent the primary site of the infection. Inhibiting or reducing cell surface availability of ACE2 represents a promising therapy for tackling COVID-19. In this context, most ACE2–based therapeutic strategies have aimed to tackle the virus through the use of angiotensin-converting enzyme (ACE) inhibitors or neutralizing the virus by exogenous administration of ACE2, which does not directly aim to reduce its membrane availability. However, through this review, we present a different perspective focusing on the subcellular localization and trafficking of ACE2. Membrane targeting of ACE2, and shedding and cellular trafficking pathways including the internalization are not well elucidated in literature. Therefore, we hereby present an overview of the fate of newly synthesized ACE2, its post translational modifications, and what is known of its trafficking pathways. In addition, we highlight the possibility that some of the identified ACE2 missense variants might affect its trafficking efficiency and localization and hence may explain some of the observed variable severity of SARS-CoV-2 infections. Moreover, an extensive understanding of these processes is necessarily required to evaluate the potential use of ACE2 as a credible therapeutic target.

scholarly journals Synthesis and immunological evaluation of synthetic peptide based anti-SARS-CoV-2 vaccine candidates

2021 ◽  
Author(s):  
Qingyu Zhao ◽  
Yanan Gao ◽  
Min Xiao ◽  
Xuefei Huang ◽  
Xuanjun Wu
Keyword(s):  
Synthetic Peptide ◽  
Spike Protein ◽  
Effective Vaccine ◽  
The Novel ◽  
Vaccine Candidates ◽  
Peptide Epitopes ◽  
Novel Coronavirus ◽  
Immunological Evaluation

For prevention of the coronavirus disease 2019 caused by the novel coronavirus SARS-CoV-2, an effective vaccine is critical. Herein, several potential peptide epitopes from the spike protein of SARS-CoV-2 have...

scholarly journals Role of Structural and Non-Structural Proteins and Therapeutic Targets of SARS-CoV-2 for COVID-19

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 821
Author(s):  
Rohitash Yadav ◽  
Jitendra Kumar Chaudhary ◽  
Neeraj Jain ◽  
Pankaj Kumar Chaudhary ◽  
Supriya Khanra ◽  
...  
Keyword(s):  
Host Cell ◽  
Protein S ◽  
Structural Similarity ◽  
Cell Receptor ◽  
Molecular Assembly ◽  
The Body ◽  
Spike Protein ◽  
Structural Proteins ◽  
Structural Protein ◽  
Novel Coronavirus

Coronavirus belongs to the family of Coronaviridae, comprising single-stranded, positive-sense RNA genome (+ ssRNA) of around 26 to 32 kilobases, and has been known to cause infection to a myriad of mammalian hosts, such as humans, cats, bats, civets, dogs, and camels with varied consequences in terms of death and debilitation. Strikingly, novel coronavirus (2019-nCoV), later renamed as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and found to be the causative agent of coronavirus disease-19 (COVID-19), shows 88% of sequence identity with bat-SL-CoVZC45 and bat-SL-CoVZXC21, 79% with SARS-CoV and 50% with MERS-CoV, respectively. Despite key amino acid residual variability, there is an incredible structural similarity between the receptor binding domain (RBD) of spike protein (S) of SARS-CoV-2 and SARS-CoV. During infection, spike protein of SARS-CoV-2 compared to SARS-CoV displays 10–20 times greater affinity for its cognate host cell receptor, angiotensin-converting enzyme 2 (ACE2), leading proteolytic cleavage of S protein by transmembrane protease serine 2 (TMPRSS2). Following cellular entry, the ORF-1a and ORF-1ab, located downstream to 5′ end of + ssRNA genome, undergo translation, thereby forming two large polyproteins, pp1a and pp1ab. These polyproteins, following protease-induced cleavage and molecular assembly, form functional viral RNA polymerase, also referred to as replicase. Thereafter, uninterrupted orchestrated replication-transcription molecular events lead to the synthesis of multiple nested sets of subgenomic mRNAs (sgRNAs), which are finally translated to several structural and accessory proteins participating in structure formation and various molecular functions of virus, respectively. These multiple structural proteins assemble and encapsulate genomic RNA (gRNA), resulting in numerous viral progenies, which eventually exit the host cell, and spread infection to rest of the body. In this review, we primarily focus on genomic organization, structural and non-structural protein components, and potential prospective molecular targets for development of therapeutic drugs, convalescent plasm therapy, and a myriad of potential vaccines to tackle SARS-CoV-2 infection.

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