Potential linear B-cells epitope change to a helix structure in the spike of Omicron 21L or BA.2 predicts increased SARS-CoV-2 antibodies evasion.

The world health organization has announced that SARS-CoV-2 Omicron variant (B.1.1.529), including the three versions; 21K (BA.1), 21L (BA.2) and 21M (BA.3) as a variant of concern (VOC) on November 2022. In this study, we used the specialized computational platforms to predict the stability and flexibility of the spike protein of Omicron. The aim of this study was to investigate the expected effect of Omicron spike mutations on its physiochemical properties. Findings of this study revealed 16 stabilizing mutations that might explain a newly gained environmental stability. We expect the new mutations to play a crucial role in changing the physiochemical properties of epitopes of the spike protein. The notable finding of SuerPose work was the potential linear B-cells epitope G252 → S255 that has been changed in the spike protein of the Omicron 21L to a helix structure which might confer an escape from human monoclonal antibodies.

Dynamics prediction of emerging notable spike protein mutations in SARS-CoV-2 implies a need for updated vaccines.

The spike protein of SARS-CoV-2 plays a crucial role in binding with the human cell surface, which causes its pathogenicity. This study aimed to predict molecular dynamics change of emerging variants in the spike protein. In this study, several structural biology tools, such as SuperPose, were utilized to study spike protein structures' thermodynamics, superimposition, and the spike protein disulphide bonds. This questions the current vaccines efficacies that were based on the Nextstrain clade 19A that first documented in Wuhan and lacks any variants. The prediction results of this study have exhibited the stabilizing role of the globally dominant variant, the D614G; clade 20A, and other variants in addition to their role in increasing the flexibility of the spike protein of the virus. The SuperPose findings have revealed a conformational change impact of D614G in allowing the polybasic Furin cleavage site (682RRAR↓S686) to be closer to the receptor-binding domain (RBD) and hence more exposed to cleavage. The presence of D614G in any clade or subclade, such as 20A, B.1.1.7 (20I/501Y.V1) or Alpha, B.1.351 (20H/501Y.V2) or Beta, P.1 (20J/501Y.V3) or Gamma, B.1.617.2 (21A/478K.V1) or Delta, has increased its stability and flexibility and unified the superimposition among all clades which might impact the virus ability to escape the antibodies neutralization by changing the antigenicity drift of the protein three-dimensional (3D) structure from the wild type clade 19A; this is in agreement with previous study. In conclusion, a new design for the current vaccines to include at least the mutation D614G is immediately needed.

Mutational sensitivity of D614G in spike protein of SARS-CoV-2 in Jordan.

BACKGROUND: Spike protein is the surface glycoprotein of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) necessary for the entry of the virus via the transmembrane receptors of the human respiratory cells causing COVID-19 disease. AIM: Here, we aimed to predict the three-dimensional monomer structure of spike protein of SARS-CoV-2 from 20 Jordanian nasopharyngeal samples and to determine the percentage of single amino acid variants (SAV) in the spike protein of SARS-CoV-2. METHODS: The output of the Protein Homology/analogY Recognition Engine V 2.0 (Phyre2) found four single amino acid variants in the spike gene. RESULTS: The first variant represented by 5% of samples that showed tyrosine deletion at Y144 located in the N terminal domain. The second and the dominant variant, represented by 62%, showed aspartate a coil amino acid substitution to glycine an extracellular amino acid at D614G located in the spike recognition binding site. The third variant, represented by 5%, showed aspartate substitution to tyrosine at D1139Y, and the fourth variant, represented by 5% glycine substitution to serine at G1167S. CONCLUSION: Our results have shown low mutational sensitivity in all variants except to D614G the one with the most likely neutral mutational sensitivity that all variants might not explicitly affect the function of spike glycoprotein. However, D614G might change the viral conformational plasticity and hence a potential viral fitness gain but one must be cautious about drawing any concrete conclusions about the severity of symptoms and viral transmission from genomic data only. GENERAL SIGNIFICANCE: Studying mutations such as D614G in deep is essential to control the pandemic in terms of immune systems, antibodies, or even vaccines.

miRNA target prediction might explain the reduced transmission of SARS-CoV-2 in Jordan, Middle East.

MicroRNAs (miRNAs) are non-coding RNAs that control many functions within the human cells by controlling protein levels through binding to messenger RNA (mRNA) translation process or mRNA abundance. Many pieces of evidence show that miRNAs affect the viral RNA replication and pathogenesis through direct binding to the RNA virus to mediate changes in the host transcriptome. Many previous studies have been studying the interaction between human cells' miRNA and viral RNA to predict many targets along the viral genome. In this work, via the miRDB database, we determined the target scores of predicted human miRNA to bind with the ss-RNA of the severe acute respiratory syndrome coronavirus (SARS-CoV-2) in general and its spike gene in specific. Our predicted miRNA targets of the ss-RNA of SARS-CoV-2 might destabilize the ss-RNA translation of SARS-CoV-2 that has been established by more than 80% of asymptomatic infected cases in Jordan due to host miRNA interactions. In respiratory epithelial cells, the high prediction scoring for miRNAs covers the RNA from 5' to 3' that explains successful antiviral defenses against ss-RNA of SARS-CoV-2 and might lead to new nucleotide deletion mechanisms. The exciting findings here that the nucleotide substitution 1841A > G at the viral genomic RNA level, which is an amino acid substation D614G at the spike protein level showed a change in the predicted miRNA sequence from hsa-miR-4793-5p to hsa-miR-3620-3p with an increase in the target score from 91 to 92.