scholarly journals A rigorous framework for detecting SARS-CoV-2 spike protein mutational ensemble from genomic and structural features

Author(s):  
Saman Fatihi ◽  
Surabhi Rathore ◽  
Ankit K. Pathak ◽  
Deepanshi Gahlot ◽  
Mitali Mukerji ◽  
...  
2021 ◽  
Author(s):  
Saman Fatihi ◽  
Surabhi Rathore ◽  
Ankit Pathak ◽  
Deepanshi Gahlot ◽  
Mitali Mukerji ◽  
...  

AbstractThe recent release of SARS-CoV-2 genomic data from several countries has provided clues into the potential antigenic drift of the coronavirus population. In particular, the genomic instability observed in the spike protein necessitates immediate action and further exploration in the context of viral-host interactions. Here we dynamically track 3,11,795 genome sequences of spike protein, which comprises 2,584 protein mutations. We reveal mutational genomic ensemble at different timing and geographies, that evolves on four distinct residues. In addition to the well-established N501 mutational cluster, we detect the presence of three novel clusters, namely A222, N439, and S477. The robust examination of structural features from 44 known cryo-EM structures showed that the virus is deploying many mutations within these clusters on structurally heterogeneous regions. One such dominant variant D614G was also simulated using molecular dynamics simulations and, as compared to wild-type, we found higher stability with human ACE2 receptor. There is also a significant overlap of mutational clusters on known epitopes, indicating putative interference with antibody binding. Thus, we propose that the resulting coaxility of mutational clusters is the most efficient feature of SARS-CoV-2 evolution and provides precise mutant combinations that can enable future vaccine re-positioning.


Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2214
Author(s):  
Qilong Tang ◽  
Raymond J. Owens ◽  
James H. Naismith

Nanobodies are 130 amino acid single‑domain antibodies (VHH) derived from the unique heavy-chain-only subclass of Camelid immunogloblins. Their small molecular size, facile expression, high affinity and stability have combined to make them unique targeting reagents with numerous applications in the biomedical sciences. The first nanobody agent has now entered the clinic as a treatment against a blood disorder. The spread of the SARS-CoV-2 virus has seen the global scientific endeavour work to accelerate the development of technologies to try to defeat a pandemic that has now killed over four million people. In a remarkably short period of time, multiple studies have reported nanobodies directed against the viral Spike protein. Several agents have been tested in culture and demonstrate potent neutralisation of the virus or pseudovirus. A few agents have completed animal trials with very encouraging results showing their potential for treating infection. Here, we discuss the structural features that guide the nanobody recognition of the receptor binding domain of the Spike protein of SARS-CoV-2.


2021 ◽  
Vol 31 (2) ◽  
Author(s):  
Hadi Sedigh Ebrahim-Saraie ◽  
Behzad Dehghani ◽  
Ali Mojtahedi ◽  
Mohammad Shenagari ◽  
Meysam Hasannejad-Bibalan

BACKGROUND፡ Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the global outbreak of coronavirus disease 2019 (Covid-19), which has been considered as a pandemic by WHO. SARS-CoV-2 encodes four major structural proteins, among which spike protein has always been a main target for new vaccine studies. This in silico study aimed to investigate some physicochemical, functional, immunological, and structural features of spike protein using several bioinformatics tools.METHOD: We retrieved all SARS-CoV-2 spike protein sequences from different countries registered in NCBI GenBank. CLC Sequence Viewer was employed to translate and align the sequences, and several programs were utilized to predict B-cell epitopes. Modification sites such as phosphorylation, glycosylation, and disulfide bonds were defined. Secondary and tertiary structures of all sequences were further computed.RESULTS: Some mutations were determined, where only one (D614G) had a high prevalence. The mutations did not impact the B-cell and physicochemical properties of the spike protein. Seven disulfide bonds were specified and also predicted in several N-link glycosylation and phosphorylation sites. The results also indicated that spike protein is a non-allergen.CONCLUSION: In summary, our findings provided a deep understanding of spike protein, which can be valuable for future studies on SARS CoV-2 infections and design of new vaccines.


2021 ◽  
Author(s):  
JAYDIP DATTA

In this article Covid19 is structurally analysed to establish the pathogenic attack through its spike protein ( 1 ) The most of the bio -macromolecules starting from globular proteins to viruses with a high molecular weight average showing polymeric nature as to induce their biological activities. The tremendous infectivity mainly depends on one most important hydrodynamic properties like Zigzag nature of viral walk ( 2 ) for a specific molecular weight ( M ). Hydrodynamic s nature of mRNA –viruses like SARS-COV-2 is analysed to compute the random– zigzag motion ( 2,3) of the virus known as Radius of Gyration( Rg ) value of virus . For computation of Rg a standard curve( 4 )of Rg – M is statistically analysed with best fit regression analysis like Morgan – Morgan – Finney ( MMF ) ( 5 ) model . This zigzag – random walk ( 2 ) of SARS-COV-2 molecule computed from Rg value may be considered as fatality rate of infection ( 6 ).


2020 ◽  
Vol 94 (22) ◽  
Author(s):  
Hongxin Guan ◽  
Youwang Wang ◽  
Vanja Perčulija ◽  
Abdullah F. U. H. Saeed ◽  
Yichang Liu ◽  
...  

ABSTRACT Coronaviruses (CoV) have caused a number of major epidemics in humans and animals, including the current pandemic of coronavirus disease 2019 (COVID-19), which has brought a renewed focus on the evolution and interspecies transmission of coronaviruses. Swine acute diarrhea syndrome coronavirus (SADS-CoV), which was recently identified in piglets in southern China, is an alphacoronavirus that originates from the same genus of horseshoe bats as severe acute respiratory syndrome CoV (SARS-CoV) and that was reported to be capable of infecting cells from a broad range of species, suggesting a considerable potential for interspecies transmission. Given the importance of the coronavirus spike (S) glycoprotein in host range determination and viral entry, we report a cryo-electron microscopy (cryo-EM) structure of the SADS-CoV S trimer in the prefusion conformation at a 3.55-Å resolution. Our structure reveals that the SADS-CoV S trimer assumes an intrasubunit quaternary packing mode in which the S1 subunit N-terminal domain (S1-NTD) and the S1 subunit C-terminal domain (S1-CTD) of the same protomer pack together by facing each other in the lying-down state. SADS-CoV S has several distinctive structural features that may facilitate immune escape, such as a relatively compact architecture of the S trimer and epitope masking by glycan shielding. Comparison of SADS-CoV S with the spike proteins of the other coronavirus genera suggested that the structural features of SADS-CoV S are evolutionarily related to those of the spike proteins of the other genera rather than to the spike protein of a typical alphacoronavirus. These data provide new insights into the evolutionary relationship between spike glycoproteins of SADS-CoV and those of other coronaviruses and extend our understanding of their structural and functional diversity. IMPORTANCE In this article, we report the atomic-resolution prefusion structure of the spike protein from swine acute diarrhea syndrome coronavirus (SADS-CoV). SADS-CoV is a pathogenic alphacoronavirus that was responsible for a large-scale outbreak of fatal disease in pigs and that was reported to be capable of interspecies transmission. We describe the overall structure of the SADS-CoV spike protein and conducted a detailed analysis of its main structural elements. Our results and analyses are consistent with those of previous phylogenetic studies and suggest that the SADS-CoV spike protein is evolutionarily related to the spike proteins of betacoronaviruses, with a strong similarity in S1-NTDs and a marked divergence in S1-CTDs. Moreover, we discuss the possible immune evasion strategies used by the SADS-CoV spike protein. Our study provides insights into the structure and immune evasion strategies of the SADS-CoV spike protein and broadens the understanding of the evolutionary relationships between coronavirus spike proteins of different genera.


Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.


Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.


Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.


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