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Molecules ; 26(20)2021 Oct 13.
Article in English | MEDLINE | ID: covidwho-1526851


There have been more than 150 million confirmed cases of SARS-CoV-2 since the beginning of the pandemic in 2019. By June 2021, the mortality from such infections approached 3.9 million people. Despite the availability of a number of vaccines which provide protection against this virus, the evolution of new viral variants, inconsistent availability of the vaccine around the world, and vaccine hesitancy, in some countries, makes it unreasonable to rely on mass vaccination alone to combat this pandemic. Consequently, much effort is directed to identifying potential antiviral treatments. Marine brominated tyrosine alkaloids are recognized to have antiviral potential. We test here the antiviral capacity of fourteen marine brominated tyrosine alkaloids against five different target proteins from SARS-CoV-2, including main protease (Mpro) (PDB ID: 6lu7), spike glycoprotein (PDB ID: 6VYB), nucleocapsid phosphoprotein (PDB ID: 6VYO), membrane glycoprotein (PDB ID: 6M17), and non-structural protein 10 (nsp10) (PDB ID: 6W4H). These marine alkaloids, particularly the hexabrominated compound, fistularin-3, shows promising docking interactions with predicted binding affinities (S-score = -7.78, -7.65, -6.39, -6.28, -8.84 Kcal/mol) for the main protease (Mpro) (PDB ID: 6lu7), spike glycoprotein (PDB ID: 6VYB), nucleocapsid phosphoprotein (PDB ID: 6VYO), membrane glycoprotein (PDB ID: 6M17), and non-structural protein 10 (nsp10) (PDB ID: 6W4H), respectively, where it forms better interactions with the protein pockets than the native interaction. It also shows promising molecular dynamics, pharmacokinetics, and toxicity profiles. As such, further exploration of the antiviral properties of fistularin-3 against SARS-CoV-2 is merited.

Alkaloids/chemistry , SARS-CoV-2/metabolism , Alkaloids/isolation & purification , Alkaloids/therapeutic use , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Binding Sites , COVID-19/drug therapy , COVID-19/virology , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , Halogenation , Humans , Isoxazoles/chemistry , Isoxazoles/metabolism , Molecular Docking Simulation , Molecular Dynamics Simulation , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Structure-Activity Relationship , Tyrosine/analogs & derivatives , Tyrosine/chemistry , Tyrosine/metabolism
Molecules ; 26(20)2021 Oct 10.
Article in English | MEDLINE | ID: covidwho-1463774


A series of novel naphthopyrano[2,3-d]pyrimidin-11(12H)-one containing isoxazole nucleus 4 was synthesized under microwave irradiation and classical conditions in moderate to excellent yields upon 1,3-dipolar cycloaddition reaction using various arylnitrile oxides under copper(I) catalyst. A one-pot, three-component reaction, N-propargylation and Dimroth rearrangement were used as the key steps for the preparation of the dipolarophiles3. The structures of the synthesized compounds were established by 1H NMR, 13C NMR and HRMS-ES means. The present study aims to also predict the theoretical assembly of the COVID-19 protease (SARS-CoV-2 Mpro) and to discover in advance whether this protein can be targeted by the compounds 4a-1 and thus be synthesized. The docking scores of these compounds were compared to those of the co-crystallized native ligand inhibitor (N3) which was used as a reference standard. The results showed that all the synthesized compounds (4a-l) gave interesting binding scores compared to those of N3 inhibitor. It was found that compounds 4a, 4e and 4i achieved greatly similar binding scores and modes of interaction than N3, indicating promising affinity towards SARS-CoV-2 Mpro. On the other hand, the derivatives 4k, 4h and 4j showed binding energy scores (-8.9, -8.5 and -8.4 kcal/mol, respectively) higher than the Mpro N3 inhibitor (-7.0 kcal/mol), revealing, in their turn, a strong interaction with the target protease, although their interactions were not entirely comparable to that of the reference N3.

Antiviral Agents/chemical synthesis , Drug Design , Isoxazoles/chemistry , Pyrimidinones/chemistry , Antiviral Agents/metabolism , Antiviral Agents/therapeutic use , Binding Sites , COVID-19/drug therapy , COVID-19/virology , Click Chemistry , Coronavirus 3C Proteases/chemistry , Coronavirus 3C Proteases/metabolism , Humans , Microwaves , Molecular Docking Simulation , Protease Inhibitors/chemistry , Protease Inhibitors/metabolism , Protease Inhibitors/therapeutic use , SARS-CoV-2/isolation & purification , Structure-Activity Relationship , Thermodynamics
Biochemistry ; 60(39): 2925-2931, 2021 10 05.
Article in English | MEDLINE | ID: covidwho-1402014


Rupintrivir targets the 3C cysteine proteases of the picornaviridae family, which includes rhinoviruses and enteroviruses that cause a range of human diseases. Despite being a pan-3C protease inhibitor, rupintrivir activity is extremely weak against the homologous 3C-like protease of SARS-CoV-2. In this study, the crystal structures of rupintrivir were determined bound to enterovirus 68 (EV68) 3C protease and the 3C-like main protease (Mpro) from SARS-CoV-2. While the EV68 3C protease-rupintrivir structure was similar to previously determined complexes with other picornavirus 3C proteases, rupintrivir bound in a unique conformation to the active site of SARS-CoV-2 Mpro splitting the catalytic cysteine and histidine residues. This bifurcation of the catalytic dyad may provide a novel approach for inhibiting cysteine proteases.

Antiviral Agents/metabolism , Coronavirus 3C Proteases/metabolism , Cysteine Proteinase Inhibitors/metabolism , Isoxazoles/metabolism , Phenylalanine/analogs & derivatives , Pyrrolidinones/metabolism , SARS-CoV-2/enzymology , Valine/analogs & derivatives , Antiviral Agents/chemistry , Catalytic Domain , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/chemistry , Crystallography, X-Ray , Cysteine Proteinase Inhibitors/chemistry , Enterovirus D, Human/enzymology , Hydrogen Bonding , Isoxazoles/chemistry , Phenylalanine/chemistry , Phenylalanine/metabolism , Protein Binding , Pyrrolidinones/chemistry , Static Electricity , Valine/chemistry , Valine/metabolism