scholarly journals Stability, orientation and position preference of the stem region (residues 689-703) in Hepatitis C Virus (HCV) envelope glycoprotein E2: a molecular dynamics study

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 64
Author(s):  
Rahmad Akbar ◽  
Siti Azma Jusoh
Keyword(s):  
Molecular Dynamics ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Host Cells ◽  
Envelope Glycoproteins ◽  
St Segment ◽  
Central Helix ◽  
Charged Residues ◽  
Tm Domain

Envelope glycoproteins of Hepatitis C Virus (HCV) play an important role in the virus assembly and initial entry into host cells. Conserved charged residues of the E2 transmembrane (TM) domain were shown to be responsible for the heterodimerization with envelope glycoprotein E1. Despite intensive research on both envelope glycoproteins, the structural information is still not fully understood. Recent findings have revealed that the stem (ST) region of E2 also functions in the initial stage of the viral life cycle. We have previously shown the effect of the conserved charged residues on the TM helix monomer of E2. Here, we extended the model of the TM domain by adding the adjacent ST segment. Explicit molecular dynamics simulations were performed for the E2 amphiphilic segment of the ST region connected to the putative TM domain (residues 683-746). Structural conformation and behavior are studied and compared with the nuclear magnetic resonance (NMR)-derived segment of E2 (2KQZ.pdb). We observed that the central helix of the ST region (residues 689 - 703) remained stable as a helix in-plane to the lipid bilayer. Furthermore, the TM domain appeared to provide minimal contribution to the structural stability of the amphipathic region. This study also provides insight into the orientation and positional preferences of the ST segment with respect to the membrane lipid-water interface.

scholarly journals Contribution of the charged residues of hepatitis C virus glycoprotein E2 transmembrane domain to the functions of the E1E2 heterodimer

2005 ◽  
Vol 86 (10) ◽  
pp. 2793-2798 ◽  
Author(s):  
Yann Ciczora ◽  
Nathalie Callens ◽  
Claire Montpellier ◽  
Birke Bartosch ◽  
François-Loïc Cosset ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Transmembrane Domain ◽  
Envelope Glycoproteins ◽  
Retention Function ◽  
Virus Glycoprotein ◽  
Er Retention ◽  
Charged Residues ◽  
Tm Domain

The envelope glycoproteins of Hepatitis C virus (HCV), E1 and E2, form a heterodimer that is retained in the endoplasmic reticulum (ER). The transmembrane (TM) domains play a major role in E1E2 heterodimerization and in ER retention. Two fully conserved charged residues in the middle of the TM domain of E2 (Asp and Arg) are crucial for these functions. Replacement of the Asp residue by a Leu impaired E1E2 heterodimerization, whereas the Arg-to-Leu mutation had a milder effect. Both Asp and Arg residues were shown to contribute to the ER retention function of E2. In addition, the entry function of HCV envelope glycoproteins was affected by these mutations. Together, these data indicate that the charged residues present in the TM domain of E2 play a major role in the biogenesis and the entry function of the E1E2 heterodimer. However, the Asp and Arg residues do not contribute equally to these functions.

scholarly journals Characterization of Hepatitis C Virus Interaction with Heparan Sulfate Proteoglycans

2015 ◽  
Vol 89 (7) ◽  
pp. 3846-3858 ◽  
Author(s):  
Yan Xu ◽  
Pierre Martinez ◽  
Karin Séron ◽  
Guangxiang Luo ◽  
Fabrice Allain ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Apolipoprotein E ◽  
Heparan Sulfate ◽  
Heparan Sulfate Proteoglycans ◽  
Hcv Infection ◽  
Host Cells ◽  
Envelope Glycoproteins ◽  
Length Unit

ABSTRACTHepatitis C virus (HCV) entry involves binding to cell surface heparan sulfate (HS) structures. However, due to the lipoprotein-like structure of HCV, the exact contribution of virion components to this interaction remains controversial. Here, we investigated the relative contribution of HCV envelope proteins and apolipoprotein E in the HS-binding step. Deletion of hypervariable region 1, a region previously proposed to be involved in HS binding, did not alter HCV virion binding to HS, indicating that this region is not involved in this interaction in the context of a viral infection. Patient sera and monoclonal antibodies recognizing different regions of HCV envelope glycoproteins were also used in a pulldown assay with beads coated with heparin, a close HS structural homologue. Although isolated HCV envelope glycoproteins could interact with heparin, none of these antibodies was able to interfere with the virion-heparin interaction, strongly suggesting that at the virion surface, HCV envelope glycoproteins are not accessible for HS binding. In contrast, results from kinetic studies, heparin pulldown experiments, and inhibition experiments with anti-apolipoprotein E antibodies indicated that this apolipoprotein plays a major role in HCV-HS interaction. Finally, characterization of the HS structural determinants required for HCV infection by silencing of the enzymes involved in the HS biosynthesis pathway and by competition with modified heparin indicated thatN- and 6-O-sulfation but not 2-O-sulfation is required for HCV infection and that the minimum HS oligosaccharide length required for HCV infection is a decasaccharide. Together, these data indicate that HCV hijacks apolipoprotein E to initiate its interaction with specific HS structures.IMPORTANCEHepatitis C is a global health problem. Hepatitis C virus (HCV) infects approximately 130 million individuals worldwide, with the majority of cases remaining undiagnosed and untreated. In most infected individuals, the virus evades the immune system and establishes a chronic infection. As a consequence, hepatitis C is the leading cause of cirrhosis, end-stage liver disease, hepatocellular carcinoma, and liver transplantation. Virus infection is initiated by entry of the virus into the host cell. In this study, we provide new insights into the viral and cellular determinants involved in the first step of HCV entry, the binding of the virus to host cells. We show that apolipoprotein E is likely responsible for virus binding to heparan sulfate and thatN- and 6-O-sulfation of the heparan sulfate proteoglycans is required for HCV infection. In addition, the minimal HS length unit required for HCV infection is a decasaccharide.

scholarly journals Structure-Based Design of Hepatitis C Virus E2 Glycoprotein Improves Serum Binding and Cross-Neutralization

2020 ◽  
Vol 94 (22) ◽  
Author(s):  
Brian G. Pierce ◽  
Zhen-Yong Keck ◽  
Ruixue Wang ◽  
Patrick Lau ◽  
Kyle Garagusi ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Viral Escape ◽  
Envelope Glycoproteins ◽  
Effective Vaccine ◽  
Immunogenic Region ◽  
Antigenic Properties ◽  
Cross Neutralization

ABSTRACT An effective vaccine for hepatitis C virus (HCV) is a major unmet need, and it requires an antigen that elicits immune responses to key conserved epitopes. Based on structures of antibodies targeting HCV envelope glycoprotein E2, we designed immunogens to modulate the structure and dynamics of E2 and favor induction of broadly neutralizing antibodies (bNAbs) in the context of a vaccine. These designs include a point mutation in a key conserved antigenic site to stabilize its conformation, as well as redesigns of an immunogenic region to add a new N-glycosylation site and mask it from antibody binding. Designs were experimentally characterized for binding to a panel of human monoclonal antibodies (HMAbs) and the coreceptor CD81 to confirm preservation of epitope structure and preferred antigenicity profile. Selected E2 designs were tested for immunogenicity in mice, with and without hypervariable region 1, which is an immunogenic region associated with viral escape. One of these designs showed improvement in polyclonal immune serum binding to HCV pseudoparticles and neutralization of isolates associated with antibody resistance. These results indicate that antigen optimization through structure-based design of the envelope glycoproteins is a promising route to an effective vaccine for HCV. IMPORTANCE Hepatitis C virus infects approximately 1% of the world’s population, and no vaccine is currently available. Due to the high variability of HCV and its ability to actively escape the immune response, a goal of HCV vaccine design is to induce neutralizing antibodies that target conserved epitopes. Here, we performed structure-based design of several epitopes of the HCV E2 envelope glycoprotein to engineer its antigenic properties. Designs were tested in vitro and in vivo, demonstrating alteration of the E2 antigenic profile in several cases, and one design led to improvement of cross-neutralization of heterologous viruses. This represents a proof of concept that rational engineering of HCV envelope glycoproteins can be used to modulate E2 antigenicity and optimize a vaccine for this challenging viral target.

scholarly journals Transmembrane Domains of Hepatitis C Virus Envelope Glycoproteins: Residues Involved in E1E2 Heterodimerization and Involvement of These Domains in Virus Entry

2006 ◽  
Vol 81 (5) ◽  
pp. 2372-2381 ◽  
Author(s):  
Yann Ciczora ◽  
Nathalie Callens ◽  
François Penin ◽  
Eve-Isabelle Pécheur ◽  
Jean Dubuisson
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Mutational Analysis ◽  
Virus Entry ◽  
Envelope Glycoproteins ◽  
Insertion Mutagenesis ◽  
Virus Envelope ◽  
Central Regions ◽  
Tm Domain

ABSTRACT The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.

scholarly journals Structural characterization of the Hepatitis C Virus E2 glycoprotein: computational and experimental approaches

2016 ◽  
Author(s):  
Daniela Barone ◽  
Nicole Balasco ◽  
Ida Autiero ◽  
Luigi Vitagliano
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Current Knowledge ◽  
Host Cells ◽  
Global Dynamics ◽  
Dynamic Features ◽  
Virus Envelope ◽  
Structural Dynamic ◽  
E2 Glycoprotein

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. Although effective therapeutic approaches, based on specific inhibitors of HCV proteins NS3/4A and NS5B, have been recently discovered, their use is limited by the elevated costs of these drugs. Currently, there is neither an effective immune globulin for prophylaxis nor a vaccine for the prevention of hepatitis C. A particularly attracting target is represented by the immunogenic E2 glycoprotein, a key factor for HCV entry in host cells. This protein has been the subject of recent structural studies that have greatly expand our current knowledge of HCV pathogenicity (Khan et al. 2015; Khan et al. 2014; Kong et al. 2013). In this framework, we have recently undertaken studies aimed at evaluating the potential of some regions of the protein as vaccine candidates (Sandomenico et al. 2015, under review). We here investigated the structural/dynamic features of the E2 protein, whose structure has been recently solved by two independent groups in complex with antibodies. Molecular dynamics simulations carried out on the protein core provided interesting information on both global dynamics of the protein and on local features of important regions. Moreover, a combined experimental/computational analysis shows that the epitope I region (residues 412-422) is endowed with an elevated structural versatility. Collectively these findings provide useful information for future studies aimed at designing anti-HCV vaccines.ReferencesKhan AG, Miller MT, and Marcotrigiano J. 2015. HCV glycoprotein structures: what to expect from the unexpected. Current opinion in virology 12:53-58. 10.1016/j.coviro.2015.02.004 Khan AG, Whidby J, Miller MT, Scarborough H, Zatorski AV, Cygan A, Price AA, Yost SA, Bohannon CD, Jacob J, Grakoui A, and Marcotrigiano J. 2014. Structure of the core ectodomain of the hepatitis C virus envelope glycoprotein 2. Nature 509:381-384. 10.1038/nature13117 Kong L, Giang E, Nieusma T, Kadam RU, Cogburn KE, Hua Y, Dai X, Stanfield RL, Burton DR, Ward AB, Wilson IA, and Law M. 2013. Hepatitis C virus E2 envelope glycoprotein core structure. Science 342:10901094. 10.1126/science.1243876

scholarly journals Structural characterization of the Hepatitis C Virus E2 glycoprotein: computational and experimental approaches

2016 ◽  
Author(s):  
Daniela Barone ◽  
Nicole Balasco ◽  
Ida Autiero ◽  
Luigi Vitagliano
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Current Knowledge ◽  
Host Cells ◽  
Global Dynamics ◽  
Dynamic Features ◽  
Virus Envelope ◽  
Structural Dynamic ◽  
E2 Glycoprotein

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. Although effective therapeutic approaches, based on specific inhibitors of HCV proteins NS3/4A and NS5B, have been recently discovered, their use is limited by the elevated costs of these drugs. Currently, there is neither an effective immune globulin for prophylaxis nor a vaccine for the prevention of hepatitis C. A particularly attracting target is represented by the immunogenic E2 glycoprotein, a key factor for HCV entry in host cells. This protein has been the subject of recent structural studies that have greatly expand our current knowledge of HCV pathogenicity (Khan et al. 2015; Khan et al. 2014; Kong et al. 2013). In this framework, we have recently undertaken studies aimed at evaluating the potential of some regions of the protein as vaccine candidates (Sandomenico et al. 2015, under review). We here investigated the structural/dynamic features of the E2 protein, whose structure has been recently solved by two independent groups in complex with antibodies. Molecular dynamics simulations carried out on the protein core provided interesting information on both global dynamics of the protein and on local features of important regions. Moreover, a combined experimental/computational analysis shows that the epitope I region (residues 412-422) is endowed with an elevated structural versatility. Collectively these findings provide useful information for future studies aimed at designing anti-HCV vaccines.ReferencesKhan AG, Miller MT, and Marcotrigiano J. 2015. HCV glycoprotein structures: what to expect from the unexpected. Current opinion in virology 12:53-58. 10.1016/j.coviro.2015.02.004 Khan AG, Whidby J, Miller MT, Scarborough H, Zatorski AV, Cygan A, Price AA, Yost SA, Bohannon CD, Jacob J, Grakoui A, and Marcotrigiano J. 2014. Structure of the core ectodomain of the hepatitis C virus envelope glycoprotein 2. Nature 509:381-384. 10.1038/nature13117 Kong L, Giang E, Nieusma T, Kadam RU, Cogburn KE, Hua Y, Dai X, Stanfield RL, Burton DR, Ward AB, Wilson IA, and Law M. 2013. Hepatitis C virus E2 envelope glycoprotein core structure. Science 342:10901094. 10.1126/science.1243876

scholarly journals Basic Residues in Hypervariable Region 1 of Hepatitis C Virus Envelope Glycoprotein E2 Contribute to Virus Entry

2005 ◽  
Vol 79 (24) ◽  
pp. 15331-15341 ◽  
Author(s):  
Nathalie Callens ◽  
Yann Ciczora ◽  
Birke Bartosch ◽  
Ngoc Vu-Dac ◽  
François-Loïc Cosset ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Virus Entry ◽  
Hypervariable Region ◽  
High Density Lipoproteins ◽  
Type I ◽  
Amino Acid Variability ◽  
Charged Residues ◽  
Glycoprotein E2

ABSTRACT The N terminus of hepatitis C virus (HCV) envelope glycoprotein E2 contains a hypervariable region (HVR1) which has been proposed to play a role in viral entry. Despite strong amino acid variability, HVR1 is globally basic, with basic residues located at specific sequence positions. Here we show by analyzing a large number of HVR1 sequences that the frequency of basic residues at each position is genotype dependent. We also used retroviral pseudotyped particles (HCVpp) harboring genotype 1a envelope glycoproteins to study the role of HVR1 basic residues in entry. Interestingly, HCVpp infectivity globally increased with the number of basic residues in HVR1. However, a shift in position of some charged residues also modulated HCVpp infectivity. In the absence of basic residues, infectivity was reduced to the same level as that of a mutant deleted of HVR1. We also analyzed the effect of these mutations on interactions with some potential HCV receptors. Recognition of CD81 was not affected by changes in the number of charged residues, and we did not find a role for heparan sulfates in HCVpp entry. The involvement of the scavenger receptor class B type I (SR-BI) was indirectly analyzed by measuring the enhancement of infectivity of the mutants in the presence of the natural ligand of SR-BI, high-density lipoproteins (HDL). However, no correlation between the number of basic residues within HVR1 and HDL enhancement effect was observed. Despite the lack of evidence of the involvement of known potential receptors, our results demonstrate that the presence of basic residues in HVR1 facilitates virus entry.

scholarly journals Ketoamide Resistance and Hepatitis C Virus Fitness in Val55 Variants of the NS3 Serine Protease

2012 ◽  
Vol 56 (4) ◽  
pp. 1907-1915 ◽  
Author(s):  
Christoph Welsch ◽  
Sabine Schweizer ◽  
Tetsuro Shimakami ◽  
Francisco S. Domingues ◽  
Seungtaek Kim ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Molecular Mechanisms ◽  
Interaction Network ◽  
Rna Replication ◽  
Viral Fitness ◽  
Dynamics Simulation ◽  
Structural Flexibility ◽  
Residue Interaction

ABSTRACTDrug-resistant viral variants are a major issue in the use of direct-acting antiviral agents in chronic hepatitis C. Ketoamides are potent inhibitors of the NS3 protease, with V55A identified as mutation associated with resistance to boceprevir. Underlying molecular mechanisms are only partially understood. We applied a comprehensive sequence analysis to characterize the natural variability at Val55 within dominant worldwide patient strains. A residue-interaction network and molecular dynamics simulation were applied to identify mechanisms for ketoamide resistance and viral fitness in Val55 variants. An infectious H77S.3 cell culture system was used for variant phenotype characterization. We measured antiviral 50% effective concentration (EC50) and fold changes, as well as RNA replication and infectious virus yields from viral RNAs containing variants. Val55 was found highly conserved throughout all hepatitis C virus (HCV) genotypes. The conservative V55A and V55I variants were identified from HCV genotype 1a strains with no variants in genotype 1b. Topology measures from a residue-interaction network of the protease structure suggest a potential Val55 key role for modulation of molecular changes in the protease ligand-binding site. Molecular dynamics showed variants with constricted binding pockets and a loss of H-bonded interactions upon boceprevir binding to the variant proteases. These effects might explain low-level boceprevir resistance in the V55A variant, as well as the Val55 variant, reduced RNA replication capacity. Higher structural flexibility was found in the wild-type protease, whereas variants showed lower flexibility. Reduced structural flexibility could impact the Val55 variant's ability to adapt for NS3 domain-domain interaction and might explain the virus yield drop observed in variant strains.

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