Relation of ACE2 with co-morbidity factors in SARS-CoV-2 pathogenicity.

In the last 3 years of the pandemic situation, SARS-CoV-2 caused a significant number of deaths. Infection rates for symptomatic and asymptomatic patients are higher than that for death. Eventually, researchers explored that the major deaths are attributed to several comorbidity factors. The confounding factors and gender-associated infection/death rate are observed globally. This suggests that SARS-CoV-2 selects the human system recognizing the internal comorbid environment. This article explored the influences of hypertension, diabetes, cardiovascular, and renovascular disorders in COVID-19 severity and mortality. Brief mechanistic layouts have been presented here, indicating some of the comorbidity as the critical determinant in the COVID-19 pathogenesis and related mortality.

Molecular dynamic simulation suggests stronger interaction of Omicron-spike with ACE2 than wild but weaker than Delta SARS-CoV-2 can be blocked by engineered S1-RBD fraction.

The SARS-CoV-2 claimed millions of lives, globally. Occurring from Wuhan (wild type) in December, 2019, it constantly mutated to Omicron (B.1.1.529), the predecessor to Delta. Omicron having ~ 32 spike mutations has variable infectivity-multiplicity-immuno-invasive properties. Understanding of its mutational effect on ACE2-binding/disease severity and developing preventive/therapeutic strategies are important. The binding affinities of Wuhan/Delta/Omicron spikes (PDB/GISAID/SWISS-MODEL) were docked (HADDOCK2.4) with ACE2 and compared by competitive-docking (PRODIGY). The protein structural stability was verified by kinetic-data/Ramachandran-plot (Zlab/UMassMedBioinfo). After several trials, a 59 amino acid (453ARG-510VAL) peptide-cut (Expasy-server) of the wild-type spike RBD with some desired mutants (THR500SER/THR500GLY/THR500ALA/THR500CYS) was blindly/competitively docked (PyMOL-V2.2.2) to block the Omicron-ACE2 binding. We examined molecular dynamic simulation (iMOD-server, with 9000 cycles/300 k-heating/1 atm pressure for system equilibration for 50 ns-run) of ACE2 and two CUTs with different SARS-CoV-2 variants. The binding-affinity of Omicron-ACE2 is slightly higher than the rest two in competitive docking setup. During individual (1:1) docking, Omicron showed little higher than wild type but much weaker binding affinity than Delta. Competitive docking suggests ten H-bonding (1.3-2.4 Å) with highly favorable energy values/Van-der-Walls-force/Haddock score for more stable-binding of Omicron-RBD with ACE2. Blind docking of different CUTs (wild/mutants) and Omicron to ACE2 completely rejected the Omicron-RBD from ACE2-target. The best blocking/binding affinity of -16.4 and -13 kcal/mole were observed in the case of THR500SER and THR500GLY, respectively, with multiple H-bonding 1.9-2.2 Å. These are supported by the MD-simulation results. So, the spike binding affinities were Delta > Omicron > wild in 1:1 docking with ACE2. Considering the wild type is non-existing nowadays, Omicron showed less ACE2 binding properties. The 59 cut of spike-RBD and its mutant THR500SER/THR500GLY may be further screened as universal blockers of this virus. Supplementary Information: The online version contains supplementary material available at 10.1007/s11224-022-02022-x.

Immunoinformatic paradigm predicts macrophage and T-cells epitope responses against globally conserved spike fragments of SARS CoV-2 for universal vaccination.

BACKGROUND: Different quickly-developed vaccines are introduced against COVID-19 with inconclusive results especially against some recent variants. Eventually, somewhere COVID-19 cases decline and in some countries it revived with some new mutant-variants (i.e. D614G, Delta and Omicron). OBJECTIVES: Proposing a universal vaccination strategy by screening globally-conserved SARS-CoV-2 spike-epitopes. METHODS: Presently, several conserved (186-countries) sequences including multiple-variants (ClustalX2) epitopic-regions (SVMTriP and IEDB) and in-silico mutants of SARS-CoV-2 spike-protein-fragments (Cut1-4) were screened for their stability against proteases, antigenicity (VaxiJen V2.0 and for glycosylation effects NetOGlyc-NetNGlyc), MHCI/II reactivity (IEDB-TOOLS) and CD4+ responses by molecular-docking (Haddock2.4/PatchDock). We also examined Molecular-Dynamic-Simulation (myPresto verson-5) of MHC-II 3LQZ with 3-Cuts and T-cell 2-molecules (1KGC/4JRX) with SM3-Cut. The MD-simulation was run with 5000-cycles after 300 k-heating/1-atm pressure adjustment for the system-equilibration. Finally, 1000 fs production was run. RESULTS: The cut4-mutant (SRLFRKSNLKPFERD) showed the highest combined-score 48.23548 and Immunogenicity-Score of 92.0887. The core-sequence SRLFRKSNL showed the highest Median-Percentile-Rank (7-HLA-allele) of 19. CD4+ immunogenicity also confirms the representation of the CUT4TM2 epitope SRLFRKSNL by MHC Class II. The epitope YNYKYRLFR from CUT4 showed an IC50 of ∼30 nM with allele HLA-DRB1*11:01 and HLA-DRB5*01:01 with plenty H-bonding. Cut4 double-mutants strongly interact with the exposed T-cell surface and are facilitated by its receptors. The MD-simulation data suggest that TM2 has a maximum RMSD value of 1.7 Å, DM2 is at 1.55 Å and SM3 is at 1.5 Å. These variations correspond to structural adjustments and involve binding/unbinding chemical interactions. The RMSD plot shows that 1KGC T-cell molecule is at 2.2 Å and the 4JRX is at 1.2 Å, which increases with the simulation time. CONCLUSIONS: Screening of conserved SARS-CoV-2 spike fragments helps to find the most stable antigenic-determinant which with some mutations showed better antigenicity. Further studies are necessary to develop global vaccination strategies against COVID-19.

Global conserved RBD fraction of SARS-CoV-2 S-protein with T500S mutation in silico significantly blocks ACE2 and rejects viral spike.

BACKGROUND: SARS-CoV-2 developed global-pandemic with millions of infections/deaths. As it is urgently necessary it is assumed that some blockers/inhibitors of ACE2 could be helpful to resist the binding of viral-spike Receptor-Binding-Domain (RBD). METHODS: Here, conserved RBD from 186-countries were compared with WUHAN-Hu-1 wild-type (CLUSTAL-X2/Pymol). The RBD of ACE2-bound nCOV2 crystal-structure 6VW1 was analyzed by Haddock-PatchDock. Extensive structural study/trial to introduce point/double/triple mutations in the different locations of CUT4 (most-effective from total 4 proposed fragments; CUTs) were tested with Swiss-Model-Expacy. RESULTS: Blind-docking of mutated-CUTs in ACE2 completely rejected the nCOV2 binding to ACE2. Further, competitive-docking/binding-analyses (by PRODIGY) demonstrated few more bonding (LYS31-PHE490 and GLN42-GLN498) of CUT4 (than wild) and hindered TYR41-THR500 interaction with ACE2. Moreover, mutated-CUT4 even showed higher blocking effect against spike-ACE2 binding. CONCLUSION: In summary, CUT4-mutant rejects whole glycosylated-nCoV2 in all pre-dock, post-dock and competitive-docking conditions. The present work strategy is relevant because it could be able to block at the first level entry of the virus to the host cells. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s41231-022-00109-5.

Better binding informatics of delta variants (B.1.617.2) with ACE2 than wild, D614G or N501Y CoV-2 is fully blocked by 84 amino-acid cut of wild spike

Background and objective The B.1.617.2 known as the Delta-variant harbors diverse Spike-mutations with developed transmissibility and immune-evasion more than wild/D614G/N501Y variants. The Delta-variant claimed comparatively a large number of lives globally. In the present study, the binding-affinities of these variants’ spikes to the human lung-ACE2 were investigated. Further, a certain portion of the spike-protein with a desired mutation was tested in-silico to block the ACE2. Methods Structure of spike-variants were retrieved from PDB/GISAID and used for homology-modeling (SWISS-MODEL). A different combination of spike-ACE2 binding 1:1 or competitive blind-docking was performed using the Haddock 2.4 web-server. Eventually, two cut-segments (84 amino-acid of wild-spike, 432–516 Cut1) and its mutant T500S;Cut 2 were screened (Swiss-model Expasy-server) as blocker/inhibitor of all spike-variants (PyMOL-V2.2.2). Results It is shown that the stability and energy of the Delta binding-affinity to ACE2 is far more than others. The number H-bonding (5), their lengths (1.7 Å-2.8 Å) and energy, Van-der-Walls energy, Haddock-score were highly favorable for more stable-binding of Delta-RBD to ACE2. The Ramachandran-plot (Zlab/UMassMed Bioinfo) data supports this. We observed the best Haddock score as −120.8±2.6 for Delta with Van-der-Walls and electrostatic-energy as −62.9 and −208.7, respectively. The highest binding-affinity (ΔG) was −10.7 kcal/mol. Its THR500 and GLN506 strongly bind with the LYS353 of ACE2. The Cut1 and its mutant T500S completely blocked Delta-spike binding to ACE2 with ΔG -8.4 and −10.6 kcal/mol, respectively. But during the comparison between 2 Cuts, Cut1 showed better results. Conclusions Fractioned spike-protein from the conserved Receptor-Binding-Domain (RBD) could universally block the virus at entry-level, thus completely protecting any intercellular metabolism. Bioinformatics is an emerging field for screening of some drug/therapeutic targets from numerous options, minimizing time and expenses.

Energetics and IC50 based epitope screening in SARS CoV-2 (COVID 19) spike protein by immunoinformatic analysis implicating for a suitable vaccine development.

BACKGROUND: The recent outbreak by SARS-CoV-2 has generated a chaos in global health and economy and claimed/infected a large number of lives. Closely resembling with SARS CoV, the present strain has manifested exceptionally higher degree of spreadability, virulence and stability possibly due to some unidentified mutations. The viral spike glycoprotein is very likely to interact with host Angiotensin-Converting Enzyme 2 (ACE2) and transmits its genetic materials and hijacks host machinery with extreme fidelity for self propagation. Few attempts have been made to develop a suitable vaccine or ACE2 blocker or virus-receptor inhibitor within this short period of time. METHODS: Here, attempt was taken to develop some therapeutic and vaccination strategies with a comparison of spike glycoproteins among SARS-CoV, MERS-CoV and the SARS-CoV-2. We verified their structure quality (SWISS-MODEL, Phyre2, and Pymol) topology (ProFunc), motifs (MEME Suite, GLAM2Scan), gene ontology based conserved domain (InterPro database) and screened several epitopes (SVMTrip) of SARS CoV-2 based on their energetics, IC50 and antigenicity with regard to their possible glycosylation and MHC/paratope binding (Vaxigen v2.0, HawkDock, ZDOCK Server) effects. RESULTS: We screened here few pairs of spike protein epitopic regions and selected their energetic, Inhibitory Concentration50 (IC50), MHC II reactivity and found some of those to be very good target for vaccination. A possible role of glycosylation on epitopic region showed profound effects on epitopic recognition. CONCLUSION: The present work might be helpful for the urgent development of a suitable vaccination regimen against SARS CoV-2.