Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications
Class I viral fusion glycoproteins facilitate fusion of the viral envelope with cell membranes and entry of the virus into the cell, through extensive short sequence-specific interactions. Regions mediating these interactions include the N-terminal hydrophobic fusion peptide, a pair of extended 4,3-...
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DRNTU::Science::Biological sciences::Microbiology::Virology DRNTU::Science::Biological sciences::Biochemistry DRNTU::Science::Biological sciences::Molecular biology Zhang, Simin Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications |
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Class I viral fusion glycoproteins facilitate fusion of the viral envelope with cell membranes and entry of the virus into the cell, through extensive short sequence-specific interactions. Regions mediating these interactions include the N-terminal hydrophobic fusion peptide, a pair of extended 4,3-hydrophobic heptad repeats (HRs), a membrane-active membrane proximal external region (MPER), a hydrophobic transmembrane domain and the cytoplasmic tail region. In particular, the anti-parallel binding of the C-terminal HR to the central N-HR trimeric coiled-coil forms the 6-helix bundle fusion core. These interaction-mediating sequences are generally well preserved sequentially and structurally, allowing their peptidyl analogues to be developed as antiviral therapeutics and/or research reagents (e.g. HR-derived peptides). Novel targets for the development of antiviral drugs and viral detection reagents are required when facing drug-resistant viral strains, viral pathogens without effective and/or economical treatment, and newly emerging viral pathogens. This thesis focuses on the systematic identification of novel interaction-mediating sequences within Class I viral fusion glycoproteins, and the investigation of their involvements in viral replication as well as their potential applications in diagnosis and anti-viral interventions.
In Paper I, peptide array scanning identified 34 spike (S) protein-derived peptides that bound to the S protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV). These putative self-binding peptides contain five core octapeptide consensus sequences, among which the octapeptide GINITNFR was predicted to form β-zipper-mediated amyloid-like fibrils. The peptide C6 containing this sequence was subsequently shown to oligomerize and form amyloid-like fibrils. The potential of C6 to conduct β-zipper-mediated interactions was further applied to detect the S protein expression by immunofluorescence staining. The peptide array scanning in Paper I used the S protein ectodomain without the MPER and beyond. Using chemical crosslinking and immunofluorescence staining, in Paper II we could show that the S protein MPER could oligomerize and further heteromerize with the N-terminal internal fusion peptide (IFP). The MPER-derived peptides also inhibited the coronavirus entry in a dose-dependent manner, potentially through disrupting the MPER-mediated interactions. The ability of peptides derived from the MPER in inhibiting viral entry and infection was subsequently studied in Paper III, in the context of HIV-1. The antiviral activities of the HIV-1 Env MPER-derived peptides were abrogated upon Ala substitution of the Trp residues or deletion of the C-terminal cholesterol-interacting motif. Unexpectedly, Ala substitutions of the Trp residues within HIV-1 Env significantly elevated the biosynthesis of another viral structural protein, the p55/Gag, which led to enhanced viral particle release. In Paper IV, besides the MPER we identified the signal sequence of HIV-1 Env as another region that could negatively regulate the expression of p55/Gag. The HIV-1 Env signal sequence, which mediates the co-translational translocalization of nascent Env polypeptide into the endoplasmic reticulum, inhibited the viral protein expression and production, probably at a post-ER-targeting stage. N-terminal truncations of the Env signal sequence significantly elevated the intracellular and intraviral levels of late viral proteins and the proviral genome transcription in a time- and dose-dependent fashion. Moreover, the truncations suppressed the HIV-1 promotor (LTR)-driven expression of a reporter protein, suggesting that the Env signal sequence inhibited viral genome transcription through LTR-dependent interactions.
This thesis focused on three novel interaction-mediating sequences within two Class I viral fusion glycoproteins, which could regulate the viral infectivity, at both viral entry and assembly, through protein-protein, protein-lipid, and/or protein-nucleic acids interactions. These sequences and the interactions that they are meditating could be further targeted by their peptidyl analogues for viral detection and/or inhibition. |
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Anders Vahlne |
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Anders Vahlne Zhang, Simin |
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Theses and Dissertations |
author |
Zhang, Simin |
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Zhang, Simin |
title |
Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications |
title_short |
Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications |
title_full |
Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications |
title_fullStr |
Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications |
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Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications |
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interaction-mediating sequences within class i viral fusion glycoproteins : their roles in viral infection and in applications |
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2015 |
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sg-ntu-dr.10356-658392023-02-28T18:51:04Z Interaction-mediating sequences within class I viral fusion glycoproteins : their roles in viral infection and in applications Zhang, Simin Anders Vahlne Alenka Jejcic James P. Tam School of Biological Sciences Karolinska Institutet DRNTU::Science::Biological sciences::Microbiology::Virology DRNTU::Science::Biological sciences::Biochemistry DRNTU::Science::Biological sciences::Molecular biology Class I viral fusion glycoproteins facilitate fusion of the viral envelope with cell membranes and entry of the virus into the cell, through extensive short sequence-specific interactions. Regions mediating these interactions include the N-terminal hydrophobic fusion peptide, a pair of extended 4,3-hydrophobic heptad repeats (HRs), a membrane-active membrane proximal external region (MPER), a hydrophobic transmembrane domain and the cytoplasmic tail region. In particular, the anti-parallel binding of the C-terminal HR to the central N-HR trimeric coiled-coil forms the 6-helix bundle fusion core. These interaction-mediating sequences are generally well preserved sequentially and structurally, allowing their peptidyl analogues to be developed as antiviral therapeutics and/or research reagents (e.g. HR-derived peptides). Novel targets for the development of antiviral drugs and viral detection reagents are required when facing drug-resistant viral strains, viral pathogens without effective and/or economical treatment, and newly emerging viral pathogens. This thesis focuses on the systematic identification of novel interaction-mediating sequences within Class I viral fusion glycoproteins, and the investigation of their involvements in viral replication as well as their potential applications in diagnosis and anti-viral interventions. In Paper I, peptide array scanning identified 34 spike (S) protein-derived peptides that bound to the S protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV). These putative self-binding peptides contain five core octapeptide consensus sequences, among which the octapeptide GINITNFR was predicted to form β-zipper-mediated amyloid-like fibrils. The peptide C6 containing this sequence was subsequently shown to oligomerize and form amyloid-like fibrils. The potential of C6 to conduct β-zipper-mediated interactions was further applied to detect the S protein expression by immunofluorescence staining. The peptide array scanning in Paper I used the S protein ectodomain without the MPER and beyond. Using chemical crosslinking and immunofluorescence staining, in Paper II we could show that the S protein MPER could oligomerize and further heteromerize with the N-terminal internal fusion peptide (IFP). The MPER-derived peptides also inhibited the coronavirus entry in a dose-dependent manner, potentially through disrupting the MPER-mediated interactions. The ability of peptides derived from the MPER in inhibiting viral entry and infection was subsequently studied in Paper III, in the context of HIV-1. The antiviral activities of the HIV-1 Env MPER-derived peptides were abrogated upon Ala substitution of the Trp residues or deletion of the C-terminal cholesterol-interacting motif. Unexpectedly, Ala substitutions of the Trp residues within HIV-1 Env significantly elevated the biosynthesis of another viral structural protein, the p55/Gag, which led to enhanced viral particle release. In Paper IV, besides the MPER we identified the signal sequence of HIV-1 Env as another region that could negatively regulate the expression of p55/Gag. The HIV-1 Env signal sequence, which mediates the co-translational translocalization of nascent Env polypeptide into the endoplasmic reticulum, inhibited the viral protein expression and production, probably at a post-ER-targeting stage. N-terminal truncations of the Env signal sequence significantly elevated the intracellular and intraviral levels of late viral proteins and the proviral genome transcription in a time- and dose-dependent fashion. Moreover, the truncations suppressed the HIV-1 promotor (LTR)-driven expression of a reporter protein, suggesting that the Env signal sequence inhibited viral genome transcription through LTR-dependent interactions. This thesis focused on three novel interaction-mediating sequences within two Class I viral fusion glycoproteins, which could regulate the viral infectivity, at both viral entry and assembly, through protein-protein, protein-lipid, and/or protein-nucleic acids interactions. These sequences and the interactions that they are meditating could be further targeted by their peptidyl analogues for viral detection and/or inhibition. DOCTOR OF PHILOSOPHY (SBS) 2015-12-23T05:55:38Z 2015-12-23T05:55:38Z 2015 2015 Thesis https://hdl.handle.net/10356/65839 10.32657/10356/65839 en 90 p. application/pdf |