Sinapic Acid Suppresses SARS CoV-2 Replication by Targeting Its Envelope Protein

SARS CoV-2 is still considered a global health issue, and its threat keeps growing with the emergence of newly evolved strains. Despite the success in developing some vaccines as a protective measure, finding cost-effective treatments is urgent. Accordingly, we screened a number of phenolic natural compounds for their in vitro anti-SARS CoV-2 activity. We found sinapic acid (SA) selectively inhibited the viral replication in vitro with an half-maximal inhibitory concentration (IC50) value of 2.69 µg/mL with significantly low cytotoxicity (CC50 = 189.3 µg/mL). Subsequently, we virtually screened all currently available molecular targets using a multistep in silico protocol to find out the most probable molecular target that mediates this compound’s antiviral activity. As a result, the viral envelope protein (E-protein) was suggested as the most possible hit for SA. Further in-depth molecular dynamic simulation-based investigation revealed the essential structural features of SA antiviral activity and its binding mode with E-protein. The structural and experimental results presented in this study strongly recommend SA as a promising structural motif for anti-SARS CoV-2 agent development.

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The YXXL Sequences of a Transmembrane Protein of Bovine Leukemia Virus Are Required for Viral Entry and Incorporation of Viral Envelope Protein into Virions

Journal of Virology ◽

10.1128/jvi.73.2.1293-1301.1999 ◽

1999 ◽

Vol 73 (2) ◽

pp. 1293-1301 ◽

Cited By ~ 21

Author(s):

Kazunori Inabe ◽

Masako Nishizawa ◽

Shigeru Tajima ◽

Kazuyoshi Ikuta ◽

Yoko Aida

Keyword(s):

Viral Entry ◽

Envelope Protein ◽

Bovine Leukemia Virus ◽

Leukemia Virus ◽

Transient Transfection ◽

Viral Envelope ◽

Tyrosine Residue ◽

Wild Type ◽

Viral Envelope Protein

ABSTRACT The cytoplasmic domain of an envelope transmembrane glycoprotein (gp30) of bovine leukemia virus (BLV) has two overlapping copies of the (YXXL)2 motif. The N-terminal motif has been implicated in in vitro signal transduction pathways from the external to the intracellular compartment and is also involved in infection and maintenance of high viral loads in sheep that have been experimentally infected with BLV. To determine the role of YXXL sequences in the replication of BLV in vitro, we changed the tyrosine or leucine residues of the N-terminal motif in an infectious molecular clone of BLV, pBLV-IF, to alanine to produce mutated proviruses designated Y487A, L490A, Y498A, L501A, and Y487/498A. Transient transfection of African green monkey kidney COS-1 cells with proviral DNAs that encoded wild-type and mutant sequences revealed that all of the mutated proviral DNAs synthesized mature envelope proteins and released virus particles into the growth medium. However, serial passages of fetal lamb kidney (FLK) cells, which are sensitive to infection with BLV, after transient transfection revealed that mutation of a second tyrosine residue in the N-terminal motif completely prevented the propagation of the virus. Similarly, Y498A and Y487/498A mutant BLV that was produced by the stably transfected COS-1 cells exhibited significantly reduced levels of cell-free virion-mediated transmission. Analysis of the protein compositions of mutant viruses demonstrated that lower levels of envelope protein were incorporated by two of the mutant virions than by wild-type and other mutant virions. Furthermore, a mutation of a second tyrosine residue decreased the specific binding of BLV particles to FLK cells and the capacity for viral penetration. Our data indicate that the YXXL sequences play critical roles in both viral entry and the incorporation of viral envelope protein into the virion during the life cycle of BLV.

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Identification and characterization of a novel envelope protein in Rana grylio virus

Journal of General Virology ◽

10.1099/vir.0.2008/000810-0 ◽

2008 ◽

Vol 89 (8) ◽

pp. 1866-1872 ◽

Cited By ~ 31

Author(s):

Zhe Zhao ◽

Fei Ke ◽

You-Hua Huang ◽

Jiu-Gang Zhao ◽

Jian-Fang Gui ◽

...

Keyword(s):

Western Blot ◽

Envelope Protein ◽

Virus Assembly ◽

Structural Features ◽

Envelope Proteins ◽

Current Data ◽

Viral Envelope ◽

Viral Envelope Protein ◽

Infected Cells

Viral envelope proteins have been proposed to play significant roles in virus infection and assembly. In this study, an envelope protein gene, 53R, was cloned and characterized from Rana grylio virus (RGV), a member of the family Iridoviridae. Database searches found its homologues in all sequenced iridoviruses, and sequence alignment revealed several conserved structural features shared by virus capsid or envelope proteins: a myristoylation site, two predicted transmembrane domains and two invariant cysteine residues. Subsequently, RT-PCR and Western blot detection revealed that the transcripts encoding RGV 53R and the protein itself appeared late during infection of fathead minnow cells and that their appearance was blocked by viral DNA replication inhibitor, indicating that RGV 53R is a late expression gene. Moreover, immunofluorescence localization found an association of 53R with virus factories in RGV-infected cells, and this association was further confirmed by expressing a 53R–GFP fusion protein in pEGFP-N3/53R-transfected cells. Furthermore, detergent extraction and Western blot detection confirmed that RGV 53R was associated with virion membrane. Therefore, the current data suggest that RGV 53R is a novel viral envelope protein and that it may play an important role in virus assembly. This is thought to be the first report on a viral envelope protein that is conserved in all sequenced iridoviruses.

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Characterization of the VP39 envelope protein from Singapore grouper iridovirus

Canadian Journal of Microbiology ◽

10.1139/cjm-2015-0118 ◽

2015 ◽

Vol 61 (12) ◽

pp. 924-937 ◽

Cited By ~ 8

Author(s):

Honglian Zhang ◽

Sheng Zhou ◽

Liqun Xia ◽

Xiaohong Huang ◽

Youhua Huang ◽

...

Keyword(s):

Envelope Protein ◽

Core Gene ◽

Immunofluorescence Assay ◽

Current Data ◽

Viral Envelope ◽

Economic Losses ◽

Immunogold Electron Microscopy ◽

Viral Envelope Protein ◽

Drug Inhibition

Singapore grouper iridovirus (SGIV) is a major pathogen that causes heavy economic losses to the grouper aquaculture industry in China and Southeast Asian countries. In the present study, a viral envelope protein, VP39, encoded by SGIV ORF39L, was identified and characterized. SGIV ORF39L was found in all sequenced iridoviruses and is now considered to be a core gene of the family Iridoviridae. ORF39L was classified as a late gene during in vitro infection using reverse transcription–polymerase chain reaction, western blotting, and a drug inhibition analysis. An indirect immunofluorescence assay revealed that the VP39 protein was confined to the cytoplasm, especially at viral assembly sites. Western blot and matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry analyses suggested that VP39 is an envelope protein. Immunogold electron microscopy further confirmed that VP39 is a viral envelope protein. Furthermore, a mouse anti-VP39 polyclonal antibody exhibited SGIV-neutralizing activity in vitro, suggesting that VP39 is involved in SGIV infection. Taken together, the current data suggest that VP39 represents a conserved envelope protein of iridoviruses that contributes to viral infection.

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Efficient Inhibition of Hepatitis B Virus Infection by Acylated Peptides Derived from the Large Viral Surface Protein

Journal of Virology ◽

10.1128/jvi.79.3.1613-1622.2005 ◽

2005 ◽

Vol 79 (3) ◽

pp. 1613-1622 ◽

Cited By ~ 219

Author(s):

Philippe Gripon ◽

Isabelle Cannie ◽

Stephan Urban

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Envelope Protein ◽

Viral Envelope ◽

Hbv Infection ◽

Viral Envelope Protein ◽

Therapeutic Concept ◽

Heparg Cell ◽

B Virus

ABSTRACT The lack of an appropriate in vitro infection system for the major human pathogen hepatitis B virus (HBV) has prevented a molecular understanding of the early infection events of HBV. We used the novel HBV-infectible cell line HepaRG and primary human hepatocytes to investigate the interference of infection by HBV envelope protein-derived peptides. We found that a peptide consisting of the authentically myristoylated N-terminal 47 amino acids of the pre-S1 domain of the large viral envelope protein (L protein) specifically prevented HBV infection, with a 50% inhibitory concentration (IC50) of 8 nM. The replacement of myristic acid with other hydrophobic moieties resulted in changes in the inhibitory activity, most notably by a decrease in the IC50 to picomolar concentrations for longer unbranched fatty acids. The obstruction of HepaRG cell susceptibility to HBV infection after short preincubation times with the peptides suggested that the peptides efficiently target and inactivate a receptor at the hepatocyte surface. Our data both shed light on the molecular mechanism of HBV entry into hepatocytes and provide a basis for the development of potent hepadnaviral entry inhibitors as a novel therapeutic concept for the treatment of hepatitis Β.

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Antiviral Peptides Targeting the West Nile Virus Envelope Protein

Journal of Virology ◽

10.1128/jvi.01840-06 ◽

2006 ◽

Vol 81 (4) ◽

pp. 2047-2055 ◽

Cited By ~ 67

Author(s):

Fengwei Bai ◽

Terrence Town ◽

Deepti Pradhan ◽

Jonathan Cox ◽

Ashish ◽

...

Keyword(s):

West Nile Virus ◽

Envelope Protein ◽

Phage Display Library ◽

Viral Envelope ◽

Host Cells ◽

Viral Envelope Protein ◽

Virus Envelope ◽

West Nile ◽

Inhibition Concentration

ABSTRACT West Nile virus (WNV) can cause fatal murine and human encephalitis. The viral envelope protein interacts with host cells. A murine brain cDNA phage display library was therefore probed with WNV envelope protein, resulting in the identification of several adherent peptides. Of these, peptide 1 prevented WNV infection in vitro with a 50% inhibition concentration of 67 μM and also inhibited infection of a related flavivirus, dengue virus. Peptide 9, a derivative of peptide 1, was a particularly potent inhibitor of WNV in vitro, with a 50% inhibition concentration of 2.6 μM. Moreover, mice challenged with WNV that had been incubated with peptide 9 had reduced viremia and fatality compared with control animals. Peptide 9 penetrated the murine blood-brain barrier and was found in the brain parenchyma, implying that it may have antiviral activity in the central nervous system. These short peptides serve as the basis for developing new therapeutics for West Nile encephalitis and, potentially, other flaviviruses.

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Antiviral activity of silymarin and baicalein against dengue virus

Scientific Reports ◽

10.1038/s41598-021-98949-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhao Xuan Low ◽

Brian Ming OuYong ◽

Pouya Hassandarvish ◽

Chit Laa Poh ◽

Babu Ramanathan

Keyword(s):

Antiviral Activity ◽

Dengue Virus ◽

Viral Entry ◽

Dengue Infection ◽

Antiviral Agents ◽

Antiviral Drug ◽

Vero Cells ◽

Viral Envelope ◽

E Protein

AbstractDengue is an arthropod-borne viral disease that has become endemic and a global threat in many countries with no effective antiviral drug available currently. This study showed that flavonoids: silymarin and baicalein could inhibit the dengue virus in vitro and were well tolerated in Vero cells with a half-maximum cytotoxic concentration (CC50) of 749.70 µg/mL and 271.03 µg/mL, respectively. Silymarin and baicalein exerted virucidal effects against DENV-3, with a selective index (SI) of 10.87 and 21.34, respectively. Baicalein showed a better inhibition of intracellular DENV-3 progeny with a SI of 7.82 compared to silymarin. Baicalein effectively blocked DENV-3 attachment (95.59%) to the Vero cells, while silymarin prevented the viral entry (72.46%) into the cells, thus reducing viral infectivity. Both flavonoids showed promising antiviral activity against all four dengue serotypes. The in silico molecular docking showed that silymarin could bind to the viral envelope (E) protein with a binding affinity of − 8.5 kcal/mol and form hydrogen bonds with the amino acids GLN120, TRP229, ASN89, and THR223 of the E protein. Overall, this study showed that silymarin and baicalein exhibited potential anti-DENV activity and could serve as promising antiviral agents for further development against dengue infection.

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Vaccinia Virus 4c (A26L) Protein on Intracellular Mature Virus Binds to the Extracellular Cellular Matrix Laminin

Journal of Virology ◽

10.1128/jvi.02302-06 ◽

2006 ◽

Vol 81 (5) ◽

pp. 2149-2157 ◽

Cited By ~ 74

Author(s):

Wen-Ling Chiu ◽

Chi-Long Lin ◽

Min-Hsiang Yang ◽

Der-Lii M. Tzou ◽

Wen Chang

Keyword(s):

Vaccinia Virus ◽

Envelope Protein ◽

Binding Activity ◽

Viral Envelope ◽

Wild Type ◽

Viral Envelope Protein ◽

Reading Frame ◽

Mature Virus ◽

Laminin Binding

ABSTRACT Vaccinia virus intracellular mature virus (IMV) binds to glycosaminoglycans (GAGs) on cells via three virion proteins, H3L, A27L, and D8L. In this study, we demonstrated that binding of IMV to BSC40 cells was competitively inhibited by soluble laminin but not by fibronectin or collagen V, suggesting that this cell surface extracellular matrix (ECM) protein may play a role in vaccinia virus entry. Moreover, IMV infection of GAG− sog9 cells was also inhibited by laminin, demonstrating that virion binding to laminin does not involve a prior interaction with GAGs. Furthermore, comparative envelope protein analyses of wild-type vaccinia virus strain Western Reserve, which binds to laminin, and of a mutant virus, IA27L, which does not, showed that the A26L open reading frame (ORF), encoding an envelope protein, was mutated in IA27L, resulting in A26L being absent from the IMV. Expression of the wild-type A26L ORF in IA27L resulted in laminin binding activity. Moreover, recombinant A26L protein bound to laminin in vitro with a high affinity, providing direct evidence that A26L is the laminin binding protein on IMV. In summary, these results reveal a novel role for the vaccinia viral envelope protein A26L in binding to the ECM protein laminin, an association that is proposed to facilitate IMV entry.

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