Santra, D. | Search bioRxiv

bioRxiv2021

Conserved in 186 countries the RBD fraction of SARS CoV-2 S-protein with in-silicoT500S mutation strongly blocks ACE2 rejecting the viral spike; A Molecular-docking analysis.

SARS-CoV-2 developed global-pandemic with millions of infections/deaths. Blocker/inhibitor of ACE2 and viral-spikes Receptor-Binding-Domain RBD-blockers are helpful. Here, conserved RBD (CUTs) from 186-countries were compared with WUHAN-Hu-1 wild-type by CLUSTAL-X2 and Structural-alignment using Pymol. The RBD of ACE2-bound nCOV2 crystal-structure (2.68[A]) 6VW1 was analyzed by Haddock-PatchDock. Extensive structural study/trial to introduce point/double/triple mutations in the following locations (Y489S/Y453S/T500S/T500Y)/(Y489S,Y453S/Y489S,T500S/Y489S,T500Y/Y453S,T500S/Y453S, T500Y)/ (Y489S,Y453S,T500S/Y489S,Y453S,T500Y) of CUT4 (most-effective) were tested with Swiss-Model-Expacy. Blind-docking of mutated-CUTs to ACE2 (6VW1) by Haddock-Hawkdock was performed and optimally complete-rejection of nCOV2 to ACE2 was noticed. Further, competitive-docking/binding-analyses were done by PRODIGY. Present results suggest that compared to the wild-spike, CUT4 showed extra LYS31-PHE490/GLN42-GLN498 bonding and lack of TYR41-THR500 interaction (in wild H-bond:2.639[A]) with ACE2 RBD. Mutated-CUT4 strongly binds with the ACE2-RBD, promoting TYR41-T500S (H-bond: 2.0[A] and 1.8[A])/T500Y (H-bond:2.6[A]) interaction and complete inhibition of ACE2 RBD-nCOV2. Mutant combinations T500S,Y489S,T500S and Y489S,Y453S,T500Y mostly blocked ACE2. Conclusively, CUT4-mutant rejects whole glycosylated-nCoV2 pre-dock/post-dock/competitive-docking conditions.

bioinformatics↗

bioRxiv2020

Energetics based epitope screening in SARS CoV-2 (COVID 19) spike glycoprotein by Immuno-informatic analysis aiming to a suitable vaccine development.

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. 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, 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/paratopic binding (Vaxigen v2.0, HawkDock, ZDOCK Server) effects. We screened here few pairs of spike protein epitopic regions and selected their energetic, 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. The present work might be helpful for the urgent development of a suitable vaccination regimen against SARS CoV-2.

immunology↗