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Gorai B, Das S, Maiti PK. Prediction and validation of HIV-1 gp41 ecto-transmembrane domain post-fusion trimeric structure using molecular modeling. J Biomol Struct Dyn 2019; 38:2592-2603. [DOI: 10.1080/07391102.2019.1635916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Biswajit Gorai
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Satyabrata Das
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Prabal K. Maiti
- Department of Physics, Indian Institute of Science, Bangalore, Karnataka, India
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2
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Guha S, Ghimire J, Wu E, Wimley WC. Mechanistic Landscape of Membrane-Permeabilizing Peptides. Chem Rev 2019; 119:6040-6085. [PMID: 30624911 DOI: 10.1021/acs.chemrev.8b00520] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Membrane permeabilizing peptides (MPPs) are as ubiquitous as the lipid bilayer membranes they act upon. Produced by all forms of life, most membrane permeabilizing peptides are used offensively or defensively against the membranes of other organisms. Just as nature has found many uses for them, translational scientists have worked for decades to design or optimize membrane permeabilizing peptides for applications in the laboratory and in the clinic ranging from antibacterial and antiviral therapy and prophylaxis to anticancer therapeutics and drug delivery. Here, we review the field of membrane permeabilizing peptides. We discuss the diversity of their sources and structures, the systems and methods used to measure their activities, and the behaviors that are observed. We discuss the fact that "mechanism" is not a discrete or a static entity for an MPP but rather the result of a heterogeneous and dynamic ensemble of structural states that vary in response to many different experimental conditions. This has led to an almost complete lack of discrete three-dimensional active structures among the thousands of known MPPs and a lack of useful or predictive sequence-structure-function relationship rules. Ultimately, we discuss how it may be more useful to think of membrane permeabilizing peptides mechanisms as broad regions of a mechanistic landscape rather than discrete molecular processes.
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Affiliation(s)
- Shantanu Guha
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Jenisha Ghimire
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Eric Wu
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - William C Wimley
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
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3
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Nieto-Garai JA, Glass B, Bunn C, Giese M, Jennings G, Brankatschk B, Agarwal S, Börner K, Contreras FX, Knölker HJ, Zankl C, Simons K, Schroeder C, Lorizate M, Kräusslich HG. Lipidomimetic Compounds Act as HIV-1 Entry Inhibitors by Altering Viral Membrane Structure. Front Immunol 2018; 9:1983. [PMID: 30233582 PMCID: PMC6131562 DOI: 10.3389/fimmu.2018.01983] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/13/2018] [Indexed: 12/16/2022] Open
Abstract
The envelope of Human Immunodeficiency Virus type 1 (HIV-1) consists of a liquid-ordered membrane enriched in raft lipids and containing the viral glycoproteins. Previous studies demonstrated that changes in viral membrane lipid composition affecting membrane structure or curvature can impair infectivity. Here, we describe novel antiviral compounds that were identified by screening compound libraries based on raft lipid-like scaffolds. Three distinct molecular structures were chosen for mode-of-action studies, a sterol derivative (J391B), a sphingosine derivative (J582C) and a long aliphatic chain derivative (IBS70). All three target the viral membrane and inhibit virus infectivity at the stage of fusion without perturbing virus stability or affecting virion-associated envelope glycoproteins. Their effect did not depend on the expressed envelope glycoproteins or a specific entry route, being equally strong in HIV pseudotypes carrying VSV-G or MLV-Env glycoproteins. Labeling with laurdan, a reporter of membrane order, revealed different membrane structure alterations upon compound treatment of HIV-1, which correlated with loss of infectivity. J582C and IBS70 decreased membrane order in distinctive ways, whereas J391B increased membrane order. The compounds' effects on membrane order were reproduced in liposomes generated from extracted HIV lipids and thus independent both of virion proteins and of membrane leaflet asymmetry. Remarkably, increase of membrane order by J391B required phosphatidylserine, a lipid enriched in the HIV envelope. Counterintuitively, mixtures of two compounds with opposite effects on membrane order, J582C and J391B, did not neutralize each other but synergistically inhibited HIV infection. Thus, altering membrane order, which can occur by different mechanisms, constitutes a novel antiviral mode of action that may be of general relevance for enveloped viruses and difficult to overcome by resistance development.
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Affiliation(s)
- Jon Ander Nieto-Garai
- Departamento de Bioquímica y Biología Molecular, Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Bilbao, Spain
| | - Bärbel Glass
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | | | | | | | - Beate Brankatschk
- JADO Technologies, Dresden, Germany.,Membrane Biochemistry Group, Paul-Langerhans-Institute Dresden, Helmholtz Zentrum München at the University Hospital and Faculty of Medicine Carl Gustav Carus, Dresden, Germany
| | - Sameer Agarwal
- JADO Technologies, Dresden, Germany.,Department of Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Kathleen Börner
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - F Xabier Contreras
- Departamento de Bioquímica y Biología Molecular, Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Bilbao, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Hans-Joachim Knölker
- JADO Technologies, Dresden, Germany.,Department of Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Claudia Zankl
- JADO Technologies, Dresden, Germany.,Department of Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Kai Simons
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Cornelia Schroeder
- JADO Technologies, Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Department of Anatomy, Medical Faculty Carl-Gustav-Carus, Technische Universität Dresden, Dresden, Germany
| | - Maier Lorizate
- Departamento de Bioquímica y Biología Molecular, Instituto Biofisika (CSIC, UPV/EHU), Universidad del País Vasco, Bilbao, Spain
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, Universitätsklinikum Heidelberg, Heidelberg, Germany
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4
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Abstract
This review summarizes over a decade of investigations into how membrane-binding proteins from the HIV-1 virus interact with lipid membrane mimics various HIV and host T-cell membranes. The goal of the work was to characterize at the molecular level both the elastic and structural changes that occur due to HIV protein/membrane interactions, which could lead to new drugs to thwart the HIV virus. The main technique used to study these interactions is diffuse X-ray scattering, which yields the bending modulus, KC, as well as structural parameters such as membrane thickness, area/lipid and position of HIV peptides (parts of HIV proteins) in the membrane. Our methods also yield information about lipid chain order or disorder caused by the peptides. This review focuses on three stages of the HIV-1 life cycle: 1) infection, 2) Tat membrane transport, and 3) budding. In the infection stage, our lab studied three different parts of HIV-1 gp41 (glycoprotein 41 fusion protein): 1) FP23, the N-terminal 23 amino acids that interact non-specifically with the T-cell host membrane to cause fusion of two membranes, and its trimer version, 2) CRAC (cholesterol recognition amino acid consensus sequence), on the MPER (membrane proximal external region) near the membrane-spanning domain, and 3) LLP2 (lentiviral lytic peptide 2) on the CTT (cytoplasmic C-terminal tail). For Tat transport, we used membrane mimics of the T-cell nuclear membrane as well as simpler models that varied charge and negative curvature. For membrane budding, we varied the myristoylation of the MA31 peptide as well as the negatively charged lipid. These studies show that HIV peptides with different roles in the HIV life cycle affect differently the relevant membrane mimics. In addition, the membrane lipid composition plays an important role in the peptides' effects.
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5
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Munsell EV, Ross NL, Sullivan MO. Journey to the Center of the Cell: Current Nanocarrier Design Strategies Targeting Biopharmaceuticals to the Cytoplasm and Nucleus. Curr Pharm Des 2016; 22:1227-44. [PMID: 26675220 DOI: 10.2174/1381612822666151216151420] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/15/2015] [Indexed: 01/06/2023]
Abstract
New biopharmaceutical molecules, potentially able to provide more personalized and effective treatments, are being identified through the advent of advanced synthetic biology strategies, sophisticated chemical synthesis approaches, and new analytical methods to assess biological potency. However, translation of many of these structures has been significantly limited due to the need for more efficient strategies to deliver macromolecular therapeutics to desirable intracellular sites of action. Engineered nanocarriers that encapsulate peptides, proteins, or nucleic acids are generally internalized into target cells via one of several endocytic pathways. These nanostructures, entrapped within endosomes, must navigate the intracellular milieu to orchestrate delivery to the intended destination, typically the cytoplasm or nucleus. For therapeutics active in the cytoplasm, endosomal escape continues to represent a limiting step to effective treatment, since a majority of nanocarriers trapped within endosomes are ultimately marked for enzymatic degradation in lysosomes. Therapeutics active in the nucleus have the added challenges of reaching and penetrating the nuclear envelope, and nuclear delivery remains a preeminent challenge preventing clinical translation of gene therapy applications. Herein, we review cutting-edge peptide- and polymer-based design strategies with the potential to enable significant improvements in biopharmaceutical efficacy through improved intracellular targeting. These strategies often mimic the activities of pathogens, which have developed innate and highly effective mechanisms to penetrate plasma membranes and enter the nucleus of host cells. Understanding these mechanisms has enabled advances in synthetic peptide and polymer design that may ultimately improve intracellular trafficking and bioavailability, leading to increased access to new classes of biotherapeutics.
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Affiliation(s)
| | | | - Millicent O Sullivan
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, Delaware.
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6
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Lü JM, Liang Z, Wang X, Gu J, Yao Q, Chen C. New polymer of lactic-co-glycolic acid-modified polyethylenimine for nucleic acid delivery. Nanomedicine (Lond) 2016; 11:1971-91. [PMID: 27456396 DOI: 10.2217/nnm-2016-0128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM To develop an improved delivery system for nucleic acids. MATERIALS & METHODS We designed, synthesized and characterized a new polymer of lactic-co-glycolic acid-modified polyethylenimine (LGA-PEI). Functions of LGA-PEI polymer were determined. RESULTS The new LGA-PEI polymer spontaneously formed nanoparticles (NPs) with DNA or RNA, and showed higher DNA or RNA loading efficiency, higher or comparable transfection efficacy, and lower cytotoxicity in several cell types including PANC-1, Jurkat and HEK293 cells, when compared with lipofectamine 2000, branched or linear PEI (25 kDa). In nude mouse models, LGA-PEI showed higher delivery efficiency of plasmid DNA or miRNA mimic into pancreatic and ovarian xenograft tumors. LGA-PEI/DNA NPs showed much lower toxicity than control PEI NPs in mouse models. CONCLUSION The new LGA-PEI polymer is a safer and more effective system to deliver DNA or RNA than PEI.
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Affiliation(s)
- Jian-Ming Lü
- Division of Surgical Research, Michael E DeBakey Department of Surgery, Baylor College of Medicine, One Plaza, Houston, TX 77030, USA
| | - Zhengdong Liang
- Division of Surgical Research, Michael E DeBakey Department of Surgery, Baylor College of Medicine, One Plaza, Houston, TX 77030, USA
| | - Xiaoxiao Wang
- Division of Surgical Research, Michael E DeBakey Department of Surgery, Baylor College of Medicine, One Plaza, Houston, TX 77030, USA
| | - Jianhua Gu
- AFM/SEM Core Facility, The Methodist Hospital Research Institute, 6670 Bertner Avenue, Houston, TX 77030, USA
| | - Qizhi Yao
- Division of Surgical Research, Michael E DeBakey Department of Surgery, Baylor College of Medicine, One Plaza, Houston, TX 77030, USA.,Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey VA Medical Center, Houston, TX 77030, USA
| | - Changyi Chen
- Division of Surgical Research, Michael E DeBakey Department of Surgery, Baylor College of Medicine, One Plaza, Houston, TX 77030, USA
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7
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Abstract
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The Dengue virus (DENV) NS2A protein,
essential for viral replication,
is a poorly characterized membrane protein. NS2A displays both protein/protein
and membrane/protein interactions, yet neither its functions in the
viral cycle nor its active regions are known with certainty. To highlight
the different membrane-active regions of NS2A, we characterized the
effects of peptides derived from a peptide library encompassing this
protein’s full length on different membranes by measuring their
membrane leakage induction and modulation of lipid phase behavior.
Following this initial screening, one region, peptide dens25, had
interesting effects on membranes; therefore, we sought to thoroughly
characterize this region’s interaction with membranes. This
peptide presents an interfacial/hydrophobic pattern characteristic
of a membrane-proximal segment. We show that dens25 strongly interacts
with membranes that contain a large proportion of lipid molecules
with a formal negative charge, and that this effect has a major electrostatic
contribution. Considering its membrane modulating capabilities, this
region might be involved in membrane rearrangements and thus be important
for the viral cycle.
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Affiliation(s)
- Henrique Nemésio
- Molecular and Cellular Biology Institute, Universitas "Miguel Hernández" , E-03202 Elche-Alicante, Spain
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8
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Nemésio H, Villalaín J. Membranotropic Regions of the Dengue Virus prM Protein. Biochemistry 2014; 53:5280-9. [DOI: 10.1021/bi500724k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Henrique Nemésio
- Instituto de Biología
Molecular y Celular, Universidad “Miguel Hernández”, E-03202 Elche-Alicante, Spain
| | - José Villalaín
- Instituto de Biología
Molecular y Celular, Universidad “Miguel Hernández”, E-03202 Elche-Alicante, Spain
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9
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Vaccine-induced HIV-1 envelope gp120 constant region 1-specific antibodies expose a CD4-inducible epitope and block the interaction of HIV-1 gp140 with galactosylceramide. J Virol 2014; 88:9406-17. [PMID: 24920809 DOI: 10.1128/jvi.01031-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Mucosal epithelial cell surface galactosylceramide (Galcer) has been postulated to be a receptor for HIV-1 envelope (Env) interactions with mucosal epithelial cells. Disruption of the HIV-1 Env interaction with such alternate receptors could be one strategy to prevent HIV-1 entry through the mucosal barrier. To study antibody modulation of HIV-1 Env-Galcer interactions, we used Galcer-containing liposomes to assess whether natural- and vaccine-induced monoclonal antibodies can block HIV-1 Env binding to Galcer. HIV-1 Env gp140 proteins bound to Galcer liposomes with Kds (dissociation constants) in the nanomolar range. Several HIV-1 ALVAC/AIDSVAX vaccinee-derived monoclonal antibodies (MAbs) specific for the gp120 first constant (C1) region blocked Galcer binding of a transmitted/founder HIV-1 Env gp140. Among the C1-specific MAbs that showed Galcer blocking, the antibody-dependent cellular cytotoxicity-mediating CH38 IgG and its natural IgA isotype were the most potent blocking antibodies. C1-specific IgG monoclonal antibodies that blocked Env binding to Galcer induced upregulation of the gp120 CD4-inducible (CD4i) epitope bound by MAb 17B, demonstrating that a conformational change in gp120 may be required for Galcer blocking. However, the MAb 17B itself did not block Env-Galcer binding, suggesting that the C1 antibody-induced gp120 conformational changes resulted in alteration in a Galcer binding site distant from the CD4i 17B MAb binding site. IMPORTANCE Galactosyl ceramide, a glycosphingolipid, has been postulated to be a receptor for the HIV-1 envelope glycoprotein (Env) interaction with mucosal epithelial cells. Here, we have mimicked this interaction by using an artificial membrane containing synthetic Galcer and recombinant HIV-1 Env proteins to identify antibodies that would block the HIV-1 Env-Galcer interaction. Our study revealed that a class of vaccine-induced human antibodies potently blocks HIV-1 Env-Galcer binding by perturbing the HIV-1 Env conformation.
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10
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Boscia AL, Akabori K, Benamram Z, Michel JA, Jablin MS, Steckbeck JD, Montelaro RC, Nagle JF, Tristram-Nagle S. Membrane structure correlates to function of LLP2 on the cytoplasmic tail of HIV-1 gp41 protein. Biophys J 2014; 105:657-66. [PMID: 23931314 DOI: 10.1016/j.bpj.2013.06.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 11/30/2022] Open
Abstract
Mutation studies previously showed that the lentivirus lytic peptide (LLP2) sequence of the cytoplasmic C-terminal tail of the HIV-1 gp41 envelope protein inhibited viral-initiated T-cell death and T-cell syncytium formation, at which time in the HIV life cycle the gp41 protein is embedded in the T-cell membrane. In striking contrast, the mutants did not affect virion infectivity, during which time the gp41 protein is embedded in the HIV envelope membrane. To examine the role of LLP2/membrane interactions, we applied synchrotron x-radiation to determine structure of hydrated membranes. We focused on WT LLP2 peptide (+3 charge) and MX2 mutant (-1 charge) with membrane mimics for the T-cell and the HIV-1 membranes. To investigate the influence of electrostatics, cholesterol content, and peptide palmitoylation, we also studied three other LLP2 variants and HIV-1 mimics without negatively charged lipids or cholesterol as well as extracted HIV-1 lipids. All LLP2 peptides bound strongly to T-cell membrane mimics, as indicated by changes in membrane structure and bending. In contrast, none of the weakly bound LLP2 variants changed the HIV-1 membrane mimic structure or properties. This correlates well with, and provides a biophysical basis for, previously published results that reported lack of a mutant effect in HIV virion infectivity in contrast to an inhibitory effect in T-cell syncytium formation. It shows that interaction of LLP2 with the T-cell membrane modulates biological function.
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Affiliation(s)
- Alexander L Boscia
- Biological Physics Group, Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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11
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Kuhlmann AS, Steckbeck JD, Sturgeon TJ, Craigo JK, Montelaro RC. Unique functional properties of conserved arginine residues in the lentivirus lytic peptide domains of the C-terminal tail of HIV-1 gp41. J Biol Chem 2014; 289:7630-40. [PMID: 24497632 PMCID: PMC3953275 DOI: 10.1074/jbc.m113.529339] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/20/2014] [Indexed: 11/06/2022] Open
Abstract
A previous study from our laboratory reported a preferential conservation of arginine relative to lysine in the C-terminal tail (CTT) of HIV-1 envelope (Env). Despite substantial overall sequence variation in the CTT, specific arginines are highly conserved in the lentivirus lytic peptide (LLP) motifs and are scarcely substituted by lysines, in contrast to gp120 and the ectodomain of gp41. However, to date, no explanation has been provided to explain the selective incorporation and conservation of arginines over lysines in these motifs. Herein, we address the functions in virus replication of the most conserved arginines by performing conservative mutations of arginine to lysine in the LLP1 and LLP2 motifs. The presence of lysine in place of arginine in the LLP1 motif resulted in significant impairment of Env expression and consequently virus replication kinetics, Env fusogenicity, and incorporation. By contrast, lysine exchanges in LLP2 only affected the level of Env incorporation and fusogenicity. Our findings demonstrate that the conservative lysine substitutions significantly affect Env functional properties indicating a unique functional role for the highly conserved arginines in the LLP motifs. These results provide for the first time a functional explanation to the preferred incorporation of arginine, relative to lysine, in the CTT of HIV-1 Env. We propose that these arginines may provide unique functions for Env interaction with viral or cellular cofactors that then influence overall Env functional properties.
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Affiliation(s)
- Anne-Sophie Kuhlmann
- From the Center for Vaccine Research and
- the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Jonathan D. Steckbeck
- From the Center for Vaccine Research and
- the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | | | - Jodi K. Craigo
- From the Center for Vaccine Research and
- the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Ronald C. Montelaro
- From the Center for Vaccine Research and
- the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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12
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Qiu J, Ashkenazi A, Liu S, Shai Y. Structural and functional properties of the membranotropic HIV-1 glycoprotein gp41 loop region are modulated by its intrinsic hydrophobic core. J Biol Chem 2013; 288:29143-50. [PMID: 23960077 DOI: 10.1074/jbc.m113.496646] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The gp41 disulfide loop region switches from a soluble state to a membrane-bound state during the human immunodeficiency virus type 1 (HIV-1) envelope-mediated membrane fusion process. The loop possesses a hydrophobic core at the center of the region with an unusual basic residue (Lys-601). Furthermore, two loop core mutations, K601A and L602A, are found to inhibit HIV-1 infectivity while keeping wild type-like levels of the envelope, implying that they exert an inhibitory effect on gp41 during the membrane fusion event. Here, we investigated the mode of action of these mutations on the loop region. We show that the K601A mutation, but not the L602A mutation, abolished the binding of a loop-specific monoclonal antibody to a loop domain peptide. Additionally, the K601A, but not the L602A, impaired disulfide bond formation in the peptides. This was correlated with changes in the circular dichroism spectrum imposed by the K601A mutation. In the membrane, however, the L602A, but not the K601A, reduced the lipid mixing ability of the loop peptides, which was correlated with decreased α-helical content of the L602A mutant. The results suggest that the Lys-601 residue provides a moderate hydrophobicity level within the gp41 loop core that contributes to the proper structure and function of the loop inside and outside the membrane. Because basic residues are found between the loop Cys residues of several lentiviral fusion proteins, the findings may contribute to understanding the fusion mechanism of other viruses as well.
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Affiliation(s)
- Jiayin Qiu
- From the Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100 Israel and
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13
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Palomares-Jerez MF, Nemesio H, Franquelim HG, Castanho MARB, Villalaín J. N-terminal AH2 segment of protein NS4B from hepatitis C virus. Binding to and interaction with model biomembranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1938-52. [PMID: 23639583 DOI: 10.1016/j.bbamem.2013.04.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 01/30/2023]
Abstract
HCV NS4B, a highly hydrophobic protein involved in the alteration of the intracellular host membranes forming the replication complex, plays a critical role in the HCV life cycle. NS4B is a multifunctional membrane protein that possesses different regions where diverse and significant functions are located. One of these important regions is the AH2 segment, which besides being highly conserved has been shown to play a significant role in NS4B functioning. We have carried out an in-depth biophysical study aimed at the elucidation of the capacity of this region to interact, modulate and disrupt membranes, as well as to study the structural and dynamic features relevant for that disruption. We show that a peptide derived from this region, NS4BAH2, is capable of specifically binding phosphatidyl inositol phosphates with high affinity, and its interfacial properties suggest that this segment could behave similarly to a pre-transmembrane domain partitioning into and interacting with the membrane depending on the membrane composition and/or other proteins. Moreover, NS4BAH2 is capable of rupturing membranes even at very low peptide-to-lipid ratios and its membrane-activity is modulated by lipid composition. NS4BAH2 is located in a shallow position in the membrane but it is able to affect the lipid environment from the membrane surface down to the hydrophobic core. The NS4B region where peptide NS4BAH2 resides might have an essential role in the membrane replication and/or assembly of the viral particle through the modulation of the membrane structure and hence the replication complex.
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14
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Palomares-Jerez F, Nemesio H, Villalaín J. The membrane spanning domains of protein NS4B from hepatitis C virus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2958-66. [DOI: 10.1016/j.bbamem.2012.07.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/23/2012] [Accepted: 07/26/2012] [Indexed: 02/08/2023]
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15
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Nemésio H, Palomares-Jerez F, Villalaín J. NS4A and NS4B proteins from dengue virus: Membranotropic regions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2818-30. [DOI: 10.1016/j.bbamem.2012.06.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 06/26/2012] [Accepted: 06/27/2012] [Indexed: 10/28/2022]
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16
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Ashkenazi A, Merklinger E, Shai Y. Intramolecular interactions within the human immunodeficiency virus-1 gp41 loop region and their involvement in lipid merging. Biochemistry 2012; 51:6981-9. [PMID: 22894130 DOI: 10.1021/bi300868f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human immunodeficiency virus utilizes its gp41 fusion protein to mediate virus-cell membrane fusion. The conserved disulfide loop region in the gp41 hairpin conformation reverses the protein chain, such that the N-terminal heptad repeat and the C-terminal heptad repeat regions interact to form the six-helix bundle. Hence, it is conceivable that the sequential folded N- and C-terminal parts of the loop region also interact. We show that the N- and C-terminal parts of the loop preferably form disulfide-bonded heterodimers with slow oxidation kinetics. Furthermore, when the two parts were linked to a single polypeptide to form the full-length loop, only an intramolecular disulfide-bonded loop was formed. Fluorescence studies revealed that an interaction takes place between the N- and C-terminal parts of the loop in solution, which was sustained in membranes. Functionally, only a combination of the N- and C-loop parts induced lipid mixing of model liposomes, the level of which increased 8-fold when they were connected to a single polypeptide chain. In both cases, the activity was independent of the oxidation state of the cysteines. Overall, the data (i) provide evidence of a specific interaction between the N- and C-terminal parts of the loop, which can further stabilize gp41 hairpin conformation, and (ii) suggest that the interaction between the N- and C-terminal parts of the loop is sufficient to induce lipid merging without forming a disulfide bond.
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Affiliation(s)
- Avraham Ashkenazi
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, 76100 Israel
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17
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Faingold O, Cohen T, Shai Y. A GxxxG-like motif within HIV-1 fusion peptide is critical to its immunosuppressant activity, structure, and interaction with the transmembrane domain of the T-cell receptor. J Biol Chem 2012; 287:33503-11. [PMID: 22872636 DOI: 10.1074/jbc.m112.370817] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To thrive in the human body, HIV fuses to its target cell and evades the immune response via several mechanisms. The fusion cascade is initiated by the fusion peptide (FP), which is located at the N-terminal of gp41, the transmembrane protein of HIV. Recently, it has been shown that the HIV-1 FP, particularly its 5-13 amino acid region (FP(5-13)), suppresses T-cell activation and interacts with the transmembrane domain (TMD) of the T-cell receptor (TCR) complex. Specific amino acid motifs often contribute to such interactions in TMDs of membrane proteins. Using bioinformatics and experimental studies, we report on a GxxxG-like motif (AxxxG), which is conserved in the FP throughout different clades and strains of HIV-1. Biological activity studies and FTIR spectroscopy revealed that HIV FP(5-13)-derived peptides, in which the motif was altered either by randomization or by a single amino acid shift, lost their immunosuppressive activity concomitant with a loss of the β-sheet structure in a membranous environment. Furthermore, fluorescence studies revealed that the inactive mutants lost their ability to interact with their target site, namely, the TMD of TCRα, designated CP. Importantly, lipotechoic acid activated macrophages (lacking TCR) were not affected by FP, further demonstrating the specificity of the immunosuppressant activity of CP. Finally, although the AxxxG WT and the GxxxG analog both associated with the CP and immunosuppressed T-cells, the AxxxG WT but not the GxxxG analog induced lipid mixing. Overall, the data support an important role for the AxxxG motif in the function of FP and might explain the natural selection of the AxxxG motif rather than the classical GxxxG motif in FP.
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Affiliation(s)
- Omri Faingold
- Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
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18
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The membrane-active regions of the dengue virus proteins C and E. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2390-402. [DOI: 10.1016/j.bbamem.2011.06.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/23/2011] [Accepted: 06/28/2011] [Indexed: 12/24/2022]
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19
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Study of the inhibition capacity of an 18-mer peptide domain of GBV-C virus on gp41-FP HIV-1 activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1567-73. [DOI: 10.1016/j.bbamem.2011.02.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 02/23/2011] [Accepted: 02/25/2011] [Indexed: 11/20/2022]
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20
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Abstract
Enveloped viruses penetrate their cell targets following the merging of their membrane with that of the cell. This fusion process is catalyzed by one or several viral glycoproteins incorporated on the membrane of the virus. These envelope glycoproteins (EnvGP) evolved in order to combine two features. First, they acquired a domain to bind to a specific cellular protein, named "receptor." Second, they developed, with the help of cellular proteins, a function of finely controlled fusion to optimize the replication and preserve the integrity of the cell, specific to the genus of the virus. Following the activation of the EnvGP either by binding to their receptors and/or sometimes the acid pH of the endosomes, many changes of conformation permit ultimately the action of a specific hydrophobic domain, the fusion peptide, which destabilizes the cell membrane and leads to the opening of the lipidic membrane. The comprehension of these mechanisms is essential to develop medicines of the therapeutic class of entry inhibitor like enfuvirtide (Fuzeon) against human immunodeficiency virus (HIV). In this chapter, we will summarize the different envelope glycoprotein structures that viruses develop to achieve membrane fusion and the entry of the virus. We will describe the different entry pathways and cellular proteins that viruses have subverted to allow infection of the cell and the receptors that are used. Finally, we will illustrate more precisely the recent discoveries that have been made within the field of the entry process, with a focus on the use of pseudoparticles. These pseudoparticles are suitable for high-throughput screenings that help in the development of natural or artificial inhibitors as new therapeutics of the class of entry inhibitors.
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Affiliation(s)
- François-Loic Cosset
- Université de Lyon, UCB-Lyon1, IFR128, Lyon, France,INSERM, U758, Lyon, France,Ecole Normale Supérieure de Lyon, Lyon, France
| | - Dimitri Lavillette
- Université de Lyon, UCB-Lyon1, IFR128, Lyon, France,INSERM, U758, Lyon, France,Ecole Normale Supérieure de Lyon, Lyon, France
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21
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Posadas I, Guerra FJ, Ceña V. Nonviral vectors for the delivery of small interfering RNAs to the CNS. Nanomedicine (Lond) 2010; 5:1219-36. [DOI: 10.2217/nnm.10.105] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
While efficient methods for cell line transfection are well described, for primary neurons a high-yield method different from those relying on viral vectors is lacking. Viral vector-based primary neuronal infection has several drawbacks, including complexity of vector preparation, safety concerns and the generation of immune and inflammatory responses, when used in vivo. This article will cover the different approaches that are being used to efficiently deliver genetic material (both DNA and small interfering RNA) to neuronal tissue using nonviral vectors, including the use of cationic lipids, polyethylenimine derivatives, dendrimers, carbon nanotubes and the combination of carbon-made nanoparticles with dendrimers. The effectiveness, both in vivo and in vitro, of the different methods to deliver genetic material to neural tissue is discussed.
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Affiliation(s)
- Inmaculada Posadas
- Unidad Asociada Neurodeath, CSIC-Universidad de Castilla-La Mancha. Departamento de Ciencias Médicas. Albacete, Spain Unidad Asociada Neurodeath, Facultad de Medicina, Avda. Almansa, 14, 02006 Albacete, Spain
- CIBERNED, Instituto de Salud Carlos III, Spain
- CIBER-BBN, Instituto de Salud Carlos III, Spain
| | - Francisco Javier Guerra
- Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Química-IRICA, Universidad de Castilla-La Mancha, Ciudad Real, Spain
- NanoDrugs, S.L. Parque Científico y Tecnológico, Albacete, Spain
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22
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HIV-1 gp41 and TCRalpha trans-membrane domains share a motif exploited by the HIV virus to modulate T-cell proliferation. PLoS Pathog 2010; 6:e1001085. [PMID: 20824090 PMCID: PMC2932719 DOI: 10.1371/journal.ppat.1001085] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 08/03/2010] [Indexed: 11/19/2022] Open
Abstract
Viruses have evolved several strategies to modify cellular processes and evade the immune response in order to successfully infect, replicate, and persist in the host. By utilizing in-silico testing of a transmembrane sequence library derived from virus protein sequences, we have pin-pointed a nine amino-acid motif shared by a group of different viruses; this motif resembles the transmembrane domain of the α-subunit of the T-cell receptor (TCRα). The most striking similarity was found within the immunodeficiency virus (SIV and HIV) glycoprotein 41 TMD (gp41 TMD). Previous studies have shown that stable interactions between TCRα and CD3 are localized to this nine amino acid motif within TCRα, and a peptide derived from it (TCRα TMD, GLRILLLKV) interfered and intervened in the TCR function when added exogenously. We now report that the gp41 TMD peptide co-localizes with CD3 within the TCR complex and inhibits T cell proliferation in vitro. However, the inhibitory mechanism of gp41 TMD differs from that of the TCRα TMD and also from the other two known immunosuppressive regions within gp41. HIV uses several mechanisms that allow it to evade immune control, in order to successfully infect, replicate, and persist in the host. Here we report a new mechanism. We utilized bioinformatics and identified a region within the transmembrane domain (TMD) of the envelop proteins of viruses that has high similarity with the α subunit of the T-cell receptor (TCR) TMD. A striking similarity was found within the immunodeficiency virus (SIV and HIV) glycoprotein 41 (gp41). TCR TMDs play an important role in the assembly of the receptor complex composed of the TCR subunits and the CD3 co-receptor chains. We show that a synthetic peptide derived from gp41 TMD co-localizes with CD3 and inhibits T-cell proliferation in vitro. Biophysical studies suggest a specific interaction between gp41 TMD and the TMD of the TCRα subunit. Importantly, the inhibitory mechanism of gp41 TMD differs from that of the other two known immunosuppressive regions within gp41. Overall, the present study demonstrates a new weapon that HIV-1 uses to penetrate into the host cell and modulates its immune response. Disassociated from HIV, however, HIV TMD molecule provides a novel mechanism for down regulating undesirable responses and might be used as a new therapy for autoimmune diseases.
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Bitler A, Lev N, Fridmann-Sirkis Y, Blank L, Cohen SR, Shai Y. Kinetics of interaction of HIV fusion protein (gp41) with lipid membranes studied by real-time AFM imaging. Ultramicroscopy 2010; 110:694-700. [DOI: 10.1016/j.ultramic.2010.02.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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24
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Pérez-Berná AJ, Pabst G, Laggner P, Villalaín J. Biophysical characterization of the fusogenic region of HCV envelope glycoprotein E1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2183-93. [PMID: 19698697 DOI: 10.1016/j.bbamem.2009.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/27/2009] [Accepted: 08/04/2009] [Indexed: 01/08/2023]
Abstract
We have studied the binding and interaction of the peptide E1(FP) with various model membranes. E1(FP) is derived from the amino acid segment 274-291 of the hepatitis C virus envelope glycoprotein E1, which was previously proposed to host the peptide responsible for fusion to target membranes. In the present study we addressed the changes which take place upon E1(FP) binding in both the peptide and the phospholipid bilayer, respectively, through a series of complementary experiments. We show that peptide E1(FP) binds to and interacts with phospholipid model membranes, modulates the polymorphic phase behavior of membrane phospholipids, is localized in a shallow position in the membrane and interacts preferentially with cholesterol. The capability of modifying the biophysical properties of model membranes supports its role in HCV-mediated membrane fusion and suggests that the mechanism of membrane fusion elicited by class I and II fusion proteins might be similar.
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Affiliation(s)
- Ana J Pérez-Berná
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, E-03202 Alicante, Spain
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25
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Guillén J, González-Alvarez A, Villalaín J. A membranotropic region in the C-terminal domain of hepatitis C virus protein NS4B interaction with membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:327-37. [PMID: 19631190 DOI: 10.1016/j.bbamem.2009.07.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 07/05/2009] [Accepted: 07/08/2009] [Indexed: 01/06/2023]
Abstract
We have identified a membrane-active region in the HCV NS4B protein by studying membrane rupture induced by a NS4B-derived peptide library on model membranes. This segment corresponds to one of two previously predicted amphipathic helix and define it as a new membrane association domain. We report the binding and interaction with model membranes of a peptide patterned after this segment, peptide NS4B(H2), and show that NS4B(H2) strongly partitions into phospholipid membranes, interacts with them, and is located in a shallow position in the membrane. Furthermore, changes in the primary sequence cause the disruption of the hydrophobicity along the structure and prevent the resulting peptide from interacting with the membrane. Our results suggest that the region where the NS4B(H2) is located might have an essential role in the membrane replication and/or assembly of the viral particle through the modulation of the replication complex. Our findings therefore identify an important region in the HCV NS4B protein which might be implicated in the HCV life cycle and possibly in the formation of the membranous web.
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Affiliation(s)
- Jaime Guillén
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, E-03202, Elche-Alicante, Spain
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26
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Lev N, Fridmann-Sirkis Y, Blank L, Bitler A, Epand RF, Epand RM, Shai Y. Conformational stability and membrane interaction of the full-length ectodomain of HIV-1 gp41: implication for mode of action. Biochemistry 2009; 48:3166-75. [PMID: 19206186 DOI: 10.1021/bi802243j] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Membrane fusion between the human immunodeficiency virus (HIV) and the target cell plasma membrane is correlated with conformational changes in the HIV gp41 glycoprotein, which include an early exposed conformation (prehairpin) and a late low energy six helix bundle (SHB) conformation also termed hairpin. Peptides resembling regions from the exposed prehairpin have been previously studied for their interaction with membranes. Here we report on the expression, purification, SHB stability, and membrane interaction of the full-length ectodomain of the HIV gp41 and its two deletion mutants, all in their SHB-folded state. The interaction of the proteins with zwitterionic and negatively charged membranes was examined by using various biophysical methods including circular dichroism spectroscopy, differential scanning calorimetry, lipid mixing of large unilamellar vesicles, and atomic force microscopy (AFM). All experiments were done in an acidic environment in which the protein remains in its soluble trimeric state. The data reveal that all three proteins fold into a stable coiled-coil core in aqueous solution and retain a stable helical fold with reduced coiled-coil characteristics in a zwitterionic and negatively charged membrane mimetic environment. Furthermore, in contrast with the extended exposed N-terminal domain, the folded gp41 ectodomain does not induce lipid mixing of zwitterionic membranes. However, it disrupts and induces lipid mixing of negatively charged phospholipid membranes (approximately 100-fold more effective than fusion peptide alone), which are known to be expressed more in HIV-1-infected T cells or macrophages. The results support the emerging model in which one of the roles of gp41 folding into the SHB conformation is to slow down membrane disruption effects induced by early exposed gp41. However, it can further affect membrane morphology once exposed to negatively charged membranes during late stages.
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Affiliation(s)
- Naama Lev
- Department of Biological Chemistry, The Weizmann Institute of Science,RehoVot, 76100 Israel
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27
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Guillén J, De Almeida RFM, Prieto M, Villalaín J. Interaction of a peptide corresponding to the loop domain of the S2 SARS-CoV virus protein with model membranes. Mol Membr Biol 2009; 26:236-48. [PMID: 19412834 PMCID: PMC7113911 DOI: 10.1080/09687680902926203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) envelope spike (S) glycoprotein is responsible for the fusion between the membranes of the virus and the target cell. In the case of the S2 domain of protein S, it has been found a highly hydrophobic and interfacial domain flanked by the heptad repeat 1 and 2 regions; significantly, different peptides pertaining to this domain have shown a significant leakage effect and an important plaque formation inhibition, which, similarly to HIV-1 gp41, support the role of this region in the fusion process. Therefore, we have carried out a study of the binding and interaction with model membranes of a peptide corresponding to segment 1073-1095 of the SARS-CoV S glycoprotein, peptide SARS(L) in the presence of different membrane model systems, as well as the structural changes taking place in both the lipid and the peptide induced by the binding of the peptide to the membrane. Our results show that SARS(L) strongly partitions into phospholipid membranes and organizes differently in lipid environments, displaying membrane activity modulated by the lipid composition of the membrane. These data would support its role in SARS-CoV mediated membrane fusion and suggest that the region where this peptide resides could be involved in the merging of the viral and target cell membranes.
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Affiliation(s)
- Jaime Guillén
- Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, Elche-Alicante, Spain
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28
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Guillén J, Kinnunen PKJ, Villalaín J. Membrane insertion of the three main membranotropic sequences from SARS-CoV S2 glycoprotein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2765-74. [PMID: 18721794 PMCID: PMC7157930 DOI: 10.1016/j.bbamem.2008.07.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 07/09/2008] [Accepted: 07/23/2008] [Indexed: 12/02/2022]
Abstract
In order to complete the fusion process of SARS-CoV virus, several regions of the S2 virus envelope glycoprotein are necessary. Recent studies have identified three membrane-active regions in the S2 domain of SARS-CoV glycoprotein, one situated downstream of the minimum furin cleavage, which is considered the fusion peptide (SARSFP), an internal fusion peptide located immediately upstream of the HR1 region (SARSIFP) and the pre-transmembrane domain (SARSPTM). We have explored the capacity of these selected membrane-interacting regions of the S2 SARS-CoV fusion protein, alone or in equimolar mixtures, to insert into the membrane as well as to perturb the dipole potential of the bilayer. We show that the three peptides interact with lipid membranes depending on lipid composition and experiments using equimolar mixtures of these peptides show that different segments of the protein may act in a synergistic way suggesting that several membrane-active regions could participate in the fusion process of the SARS-CoV.
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Affiliation(s)
- Jaime Guillén
- Instituto de Biología Molecular y Celular, Campus de Elche, Universidad Miguel Hernández, E-03202 Elche-Alicante, Spain
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29
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Guillén J, Pérez-Berná AJ, Moreno MR, Villalaín J. A second SARS-CoV S2 glycoprotein internal membrane-active peptide. Biophysical characterization and membrane interaction. Biochemistry 2008; 47:8214-24. [PMID: 18616295 DOI: 10.1021/bi800814q] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) envelope spike (S) glycoprotein, a class I viral fusion protein, is responsible for the fusion between the membranes of the virus and the target cell. The S2 domain of protein S has been suggested to have two fusion peptides, one located at its N-terminus, downstream of the furin cleavage, and another, more internal, located immediately upstream of the HR1. Therefore, we have carried out a study of the binding and interaction with model membranes of a peptide corresponding to segment 873-888 of the SARS-CoV S glycoprotein, peptide SARS IFP, as well as the structural changes taking place in both the phospholipid and the peptide induced by the binding of the peptide to the membrane. We demonstrate that SARS IFP peptide binds to and interacts with phospholipid model membranes and shows a higher affinity for negatively charged phospholipids than for zwitterionic ones. SARS IFP peptide specifically decreases the mobility of the phospholipid acyl chains of negatively charged phospholipids and adopts different conformations in the membrane depending upon their composition. These data support its role in SARS-mediated membrane fusion and suggest that the regions where this peptide resides might assist the fusion peptide and/or the pretransmembrane segment of the SARS-CoV spike glycoprotein in the fusion process.
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Affiliation(s)
- Jaime Guillén
- Instituto de Biología Molecular y Celular, Campus de Elche, Universidad Miguel Hernández, E-03202 Elche-Alicante, Spain
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30
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Kwon EJ, Bergen JM, Park IK, Pun SH. Peptide-modified vectors for nucleic acid delivery to neurons. J Control Release 2008; 132:230-5. [PMID: 18627784 DOI: 10.1016/j.jconrel.2008.06.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 06/05/2008] [Accepted: 06/13/2008] [Indexed: 12/26/2022]
Abstract
Neuron-targeted nucleic acid delivery systems are important technologies for realizing the potential of gene therapy for nervous system disorders. However, neurons are difficult cells to transfect using non-viral vectors due in part to the specific and unique delivery challenges present in these cells. We have investigated several bioactive peptides for their ability to assist in overcoming delivery barriers in mammalian cells. We summarize here our recent progress in developing and applying peptide-modified polycations for nucleic acid delivery. In addition, we present data demonstrating the potential of using multicomponent, peptide-modified polycations for nucleic acid delivery to neurons.
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Affiliation(s)
- E J Kwon
- Department of Bioengineering, University of Washington, Seattle WA 98195, USA
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31
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Galdiero S, Vitiello M, D'Isanto M, Falanga A, Cantisani M, Browne H, Pedone C, Galdiero M. The identification and characterization of fusogenic domains in herpes virus glycoprotein B molecules. Chembiochem 2008; 9:758-67. [PMID: 18311743 DOI: 10.1002/cbic.200700457] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The molecular mechanism of entry of herpes viruses requires a multicomponent fusion system. Virus entry and cell-cell fusion of Herpes simplex virus (HSV) requires four glycoproteins: gD, gB and gH/gL. The role of gB remained elusive until recently, when the crystal structure of HSV-1 gB became available. Glycoprotein B homologues represent the most highly conserved group of herpes virus glycoproteins; however, despite the high degree of sequence and structural conservation, differences in post-translational processing are observed for different members of this virus family. Whereas gB of HSV is not proteolytically processed after oligomerization, most other gB homologues are cleaved by a cellular protease into subunits that remain linked through disulfide bonds. Proteolytic cleavage is common for activation of many other viral fusion proteins, so it remains difficult to envisage a common role for different herpes virus gB structures in the fusion mechanism. We selected bovine herpes virus type 1 (BoHV-1) and herpes simplex virus type 1 (HSV-1) as representative viruses expressing cleaved and uncleaved gBs, and have screened their amino acid sequences for regions of highly interfacial hydrophobicity. Synthetic peptides corresponding to such regions were tested for their ability to induce the fusion of large unilamellar vesicles and to inhibit herpes virus infection. These results underline that several regions of the gB protein are involved in the mechanism of membrane interaction.
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Affiliation(s)
- Stefania Galdiero
- Department of Biological Sciences, Division of Biostructures, University of Naples Federico II, Via Mezzocannone 16, 80134 Napoli, Italy
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32
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Pérez‐Berná AJ, Veiga AS, Castanho MARB, Villalaín J. Hepatitis C virus core protein binding to lipid membranes: the role of domains 1 and 2. J Viral Hepat 2008; 15:346-56. [PMID: 18179451 PMCID: PMC7166730 DOI: 10.1111/j.1365-2893.2007.00948.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We have analysed and identified different membrane-active regions of the Hepatitis C virus (HCV) core protein by observing the effect of 18-mer core-derived peptide libraries from two HCV strains on the integrity of different membrane model systems. In addition, we have studied the secondary structure of specific membrane-interacting peptides from the HCV core protein, both in aqueous solution and in the presence of model membrane systems. Our results show that the HCV core protein region comprising the C-terminus of domain 1 and the N-terminus of domain 2 seems to be the most active in membrane interaction, although a role in protein-protein interaction cannot be excluded. Significantly, the secondary structure of nearly all the assayed peptides changes in the presence of model membranes. These sequences most probably play a relevant part in the biological action of HCV in lipid interaction. Furthermore, these membranotropic regions could be envisaged as new possible targets, as inhibition of its interaction with the membrane could potentially lead to new vaccine strategies.
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Affiliation(s)
- A. J. Pérez‐Berná
- Instituto de Biología Molecular y Celular, Universidad “Miguel Hernández”, Elche‐Alicante, Spain
| | - A. S. Veiga
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - M. A. R. B. Castanho
- Centro de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - J. Villalaín
- Instituto de Biología Molecular y Celular, Universidad “Miguel Hernández”, Elche‐Alicante, Spain
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33
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Moreno MR, Pérez-Berná AJ, Guillén J, Villalaín J. Biophysical characterization and membrane interaction of the most membranotropic region of the HIV-1 gp41 endodomain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1298-307. [DOI: 10.1016/j.bbamem.2007.12.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 12/19/2007] [Accepted: 12/21/2007] [Indexed: 01/04/2023]
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34
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Kwon EJ, Bergen JM, Pun SH. Application of an HIV gp41-Derived Peptide for Enhanced Intracellular Trafficking of Synthetic Gene and siRNA Delivery Vehicles. Bioconjug Chem 2008; 19:920-7. [DOI: 10.1021/bc700448h] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Role of the membrane-spanning domain of human immunodeficiency virus type 1 envelope glycoprotein in cell-cell fusion and virus infection. J Virol 2008; 82:5417-28. [PMID: 18353944 DOI: 10.1128/jvi.02666-07] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The membrane-spanning domain (MSD) of the human immunodeficiency virus type 1 (HIV-1) gp41 glycoprotein is critical for its biological activity. Previous C-terminal truncation studies have predicted an almost invariant core structure of 12 amino acid residues flanked by basic amino acids in the HIV-1 MSD that function to anchor the glycoprotein in the lipid bilayer. To further understand the role of specific amino acids within the MSD core, we initially replaced the core region with 12 leucine residues and then constructed recovery-of-function mutants in which specific amino acid residues (including a GGXXG motif) were reintroduced. We show here that conservation of the MSD core sequence is not required for normal expression, processing, intracellular transport, and incorporation into virions of the envelope glycoprotein (Env). However, the amino acid composition of the MSD core does influence the ability of Env to mediate cell-cell fusion and plays a critical role in the infectivity of HIV-1. Replacement of conserved amino acid residues with leucine blocked virus-to-cell fusion and subsequent viral entry into target cells. This restriction could not be released by C-terminal truncation of the gp41 glycoprotein. These studies imply that the highly conserved core residues of the HIV Env MSD, in addition to serving as a membrane anchor, play an important role in mediating membrane fusion during viral entry.
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36
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Aromatic amino acids in the juxtamembrane domain of severe acute respiratory syndrome coronavirus spike glycoprotein are important for receptor-dependent virus entry and cell-cell fusion. J Virol 2008; 82:2883-94. [PMID: 18199653 DOI: 10.1128/jvi.01805-07] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) spike glycoprotein (S) is a class I viral fusion protein that binds to its receptor glycoprotein, human angiotensin converting enzyme 2 (hACE2), and mediates virus entry and cell-cell fusion. The juxtamembrane domain (JMD) of S is an aromatic amino acid-rich region proximal to the transmembrane domain that is highly conserved in all coronaviruses. Alanine substitutions for one or two of the six aromatic residues in the JMD did not alter the surface expression of the SARS-CoV S proteins with a deletion of the C-terminal 19 amino acids (S Delta19) or reduce binding to soluble human ACE2 (hACE2). However, hACE2-dependent entry of trypsin-treated retrovirus pseudotyped viruses expressing JMD mutant S Delta19 proteins was greatly reduced. Single alanine substitutions for aromatic residues reduced entry to 10 to 60% of the wild-type level. The greatest reduction was caused by residues nearest the transmembrane domain. Four double alanine substitutions reduced entry to 5 to 10% of the wild-type level. Rapid hACE2-dependent S-mediated cell-cell fusion was reduced to 60 to 70% of the wild-type level for all single alanine substitutions and the Y1188A/Y1191A protein. S Delta19 proteins with other double alanine substitutions reduced cell-cell fusion further, from 40% to less than 20% of wild-type levels. The aromatic amino acids in the JMD of the SARS-CoV S glycoprotein play critical roles in receptor-dependent virus-cell and cell-cell fusion. Because the JMD is so highly conserved in all coronavirus S proteins, it is a potential target for development of drugs that may inhibit virus entry and/or cell-cell fusion mediated by S proteins of all coronaviruses.
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Pérez-Berná AJ, Guillén J, Moreno MR, Bernabeu A, Pabst G, Laggner P, Villalaín J. Identification of the membrane-active regions of hepatitis C virus p7 protein: biophysical characterization of the loop region. J Biol Chem 2008; 283:8089-101. [PMID: 18198177 DOI: 10.1074/jbc.m709413200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We have identified the membrane-active regions of the hepatitis C virus p7 protein by performing an exhaustive study of membrane rupture, hemifusion, and fusion induced by a p7-derived peptide library on model membranes having different phospholipid compositions. We report the identification in p7 of a highly membranotropic region located at the loop domain of the protein. Here, we have investigated the interaction of a peptide patterned after the p7 loop (peptide p7(L)), studying its binding and interaction with the lipid bilayer, and evaluated the binding-induced structural changes of the peptide and the phospholipids. We show that positively rich p7(L) strongly binds to negatively charged phospholipids and it is localized in a shallow position in the bilayer. Furthermore, peptide p7(L) exhibits a high tendency to oligomerize in the presence of phospholipids, which could be the driving force for the formation of the active ion channel. Therefore, our findings suggest that the p7 loop could be an attractive candidate for antiviral drug development, because it could be a target for antiviral compounds that may lead to new vaccine strategies.
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Affiliation(s)
- Ana J Pérez-Berná
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Alicante, Spain
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Costin JM, Rausch JM, Garry RF, Wimley WC. Viroporin potential of the lentivirus lytic peptide (LLP) domains of the HIV-1 gp41 protein. Virol J 2007; 4:123. [PMID: 18028545 PMCID: PMC2211469 DOI: 10.1186/1743-422x-4-123] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 11/20/2007] [Indexed: 11/10/2022] Open
Abstract
Background Mechanisms by which HIV-1 mediates reductions in CD4+ cell levels in infected persons are being intensely investigated, and have broad implications for AIDS drug and vaccine development. Virally induced changes in membrane ionic permeability induced by lytic viruses of many families contribute to cytopathogenesis. HIV-1 induces disturbances in plasma membrane ion transport. The carboxyl terminus of TM (gp41) contains potential amphipathic α-helical motifs identified through their structural similarities to naturally occurring cytolytic peptides. These sequences have been dubbed lentiviral lytic peptides (LLP) -1, -2, and -3. Results Peptides corresponding to the LLP domains (from a clade B virus) partition into lipid membranes, fold into α-helices and disrupt model membrane permeability. A peptide corresponding to the LLP-1 domain of a clade D HIV-1 virus, LLP-1D displayed similar activity to the LLP-1 domain of the clade B virus in all assays, despite a lack of amino acid sequence identity. Conclusion These results suggest that the C-terminal domains of HIV-1 Env proteins may form an ion channel, or viroporin. Increased understanding of the function of LLP domains and their role in the viral replication cycle could allow for the development of novel HIV drugs.
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Affiliation(s)
- Joshua M Costin
- Biotechnology Research Group, Department of Biology, Florida Gulf Coast University, 10501 FGCU Blvd. S., Fort Myers, FL 33965, USA.
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Guillén J, Moreno MR, Pérez-Berna AJ, Bernabeu A, Villalaín J. Interaction of a peptide from the pre-transmembrane domain of the severe acute respiratory syndrome coronavirus spike protein with phospholipid membranes. J Phys Chem B 2007; 111:13714-25. [PMID: 18020324 DOI: 10.1021/jp073675y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) envelope spike (S) glycoprotein, a Class I viral fusion protein, is responsible for the fusion between the membranes of the virus and the target cell. In order to gain new insight into the protein membrane alteration leading to the viral fusion mechanism, a peptide pertaining to the putative pre-transmembrane domain (PTM) of the S glycoprotein has been studied by infrared and fluorescence spectroscopies regarding its structure, its ability to induce membrane leakage, aggregation, and fusion, as well as its affinity toward specific phospholipids. We demonstrate that the SARS-CoV PTM peptide binds to and interacts with phospholipid model membranes, and, at the same time, it adopts different conformations when bound to membranes of different compositions. As it has been already suggested for other viral fusion proteins such as HIV gp41, the region of the SARS-CoV protein where the PTM peptide resides could be involved in the merging of the viral and target cell membranes working synergistically with other membrane-active regions of the SARS-CoV S glycoprotein to heighten the fusion process and therefore might be essential for the assistance and enhancement of the viral and cell fusion process.
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Affiliation(s)
- Jaime Guillén
- Instituto de Biología Molecular y Celular, Campus de Elche, Universidad Miguel HernAndez, E-03202 Elche-Alicante, Spain
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Abstract
The human immunodeficiency virus type 1 (HIV-1) has been intensely investigated since its discovery in 1983 as the cause of acquired immune deficiency syndrome (AIDS). With relatively few proteins made by the virus, it is able to accomplish many tasks, with each protein serving multiple functions. The Envelope glycoprotein, composed of the two noncovalently linked subunits, SU (surface glycoprotein) and TM (transmembrane glycoprotein) is largely responsible for host cell recognition and entry respectively. While the roles of the N-terminal residues of TM is well established as a fusion pore and anchor for Env into cell membranes, the role of the C-terminus of the protein is not well understood and is fiercely debated. This review gathers information on TM in an attempt to shed some light on the functional regions of this protein.
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Affiliation(s)
- Joshua M Costin
- Biotechnology Research Group, Department of Biology, Florida Gulf Coast University, 10501 FGCU Blvd, S., Fort Myers, Fl 33965, USA.
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Fatty acids can substitute the HIV fusion peptide in lipid merging and fusion: an analogy between viral and palmitoylated eukaryotic fusion proteins. J Mol Biol 2007; 374:220-30. [PMID: 17919659 DOI: 10.1016/j.jmb.2007.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2007] [Revised: 08/20/2007] [Accepted: 09/04/2007] [Indexed: 11/22/2022]
Abstract
Various fusion proteins from eukaryotes and viruses share structural similarities such as a coiled coil motif. However, compared with eukaryotic proteins, a viral fusion protein contains a fusion peptide (FP), which is an N-terminal hydrophobic fragment that is primarily involved in directing fusion via anchoring the protein to the target cell membrane. In various eukaryotic fusion proteins the membrane targeting domain is cysteine-rich and must undergo palmitoylation prior to the fusion process. Here we examined whether fatty acids can replace the FP of human immunodeficiency virus type 1 (HIV-1), thereby discerning between the contributions of the sequence versus hydrophobicity of the FP in the lipid-merging process. For that purpose, we structurally and functionally characterized peptides derived from the N terminus of HIV fusion protein - gp41 in which the FP is lacking or replaced by fatty acids. We found that fatty acid conjugation dramatically enhanced the capability of the peptides to induce lipid mixing and aggregation of zwitterionic phospholipids composing the outer leaflet of eukaryotic cell membranes. The enhanced effect of the acylated peptides on membranes was further supported by real-time atomic force microscopy (AFM) showing nanoscale holes in zwitterionic membranes. Membrane-binding experiments revealed that fatty acid conjugation did not increase the affinity of the peptides to the membrane significantly. Furthermore, all free and acylated peptides exhibited similar alpha-helical structures in solution and in zwitterionic membranes. Interestingly, the fusogenic active conformation of N36 in negatively charged membranes composing the inner leaflet of eukaryotic cells is beta-sheet. Apparently, N-terminal heptad repeat (NHR) can change its conformation as a response to a change in the charge of the membrane head group. Overall, the data suggest an analogy between the eukaryotic cysteine-rich domains and the viral fusion peptide, and mark the hydrophobic nature of FP as an important characteristic for its role in lipid merging.
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Zhu Y, Lu L, Chao L, Chen YH. Important changes in biochemical properties and function of mutated LLP12 domain of HIV-1 gp41. Chem Biol Drug Des 2007; 70:311-8. [PMID: 17850282 PMCID: PMC7188357 DOI: 10.1111/j.1747-0285.2007.00564.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The human immunodeficiency virus type 1 gp41 possesses an unusually long and conserved cytoplasmic region. Mutations in the LLP12 domain in this region have been shown to significantly affect viral competence. It is likely that the impaired infectivity of this mutated virus involves certain biochemical aspects of the peptide LLP12. To test our assumptions, some important biochemical properties and functions of LLP12 domain were studied. The recombinant peptide LLP12 (LLP12 domain on gp41, including LLP1 and LLP2 domains) was prepared via bacterial expression system. Biochemical analysis directly demonstrated its multimeric potential and membrane-binding ability. Several arginine residues in this domain were observed to be extremely highly conserved. Interestingly, the LLP12 mutants constructed by substitution of these arginine residues with alanine (separate mutations in LLP1 or LLP2 or both) showed apparent decreases in their multimeric potential and membrane-binding ability. Comparing our results with independent data on human immunodeficiency virus from other researchers, it appears that both the multimeric state and the membrane affinity of the LLP12 domain of human immunodeficiency virus type 1 gp41 could be involved in viral competence and in the mechanism of human immunodeficiency virus type 1 Env-mediated cell fusion.
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Affiliation(s)
- Yun Zhu
- Laboratory of Immunology, Department of Biology, Tsinghua University and Protein Science Laboratory of the Ministry of Education, Beijing 100084, China
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Bernabeu A, Guillén J, Pérez-Berná AJ, Moreno MR, Villalaín J. Structure of the C-terminal domain of the pro-apoptotic protein Hrk and its interaction with model membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1659-70. [PMID: 17434443 DOI: 10.1016/j.bbamem.2007.02.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 02/26/2007] [Accepted: 02/28/2007] [Indexed: 12/22/2022]
Abstract
The protein harakiri (Hrk) is a pro-apoptotic BH3-only protein which belongs to the Bcl-2 family. Hrk appears associated to the mitochondrial outer membrane, apparently by a putative transmembrane domain, where it exerts its function. In this work we have identified a 27mer peptide supposed to be the putative membrane domain of the protein at the C-terminal region, and used infrared and fluorescence spectroscopies to study its secondary structure as well as to characterize its effect on the physical properties of phospholipid model membranes. The results presented here showed that the C-terminal region of Hrk adopts a predominantly alpha-helical structure whose proportion and destabilization capability varied depending on phospholipid composition. Moreover it was found that the orientation of the alpha-helical component of this C-terminal Hrk peptide was nearly perpendicular to the plane of the membrane. These results indicate that this domain is able of inserting into membranes, where it adopts a transmembrane alpha-helical structure as well as it considerably perturbs the physical properties of the membrane.
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Affiliation(s)
- Angela Bernabeu
- Instituto de Biología Molecular y Celular, Edf. Torregaitán, Campus de Elche, Universidad Miguel Hernández, Elche, Alicante, Spain
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Chen Z, Hong L, Li Z, Fan D, Huang Q, Wang H, Li Z, Xu Z. Preparation and characterization of four novel monoclonal antibodies specific to N51(L6)C46 polypeptide simulating fusogenic core structure of GP41 subunit of HIV-1. Hybridoma (Larchmt) 2006; 25:278-82. [PMID: 17044783 DOI: 10.1089/hyb.2006.25.278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have generated monoclonal antibodies (MAbs) against the N51(L6)C46 polypeptide, which could stimulate the fusogenic core structure of the gp41 subunit of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein. Hybridomas were screened by indirect enzyme-linked immunosorbent assay (ELISA) using either N51(L6)C46 or N36(L6)C34 polypeptide. The MAb against N36(L6)C34, NC-1, was used as positive control, and N36 C34 peptides as negative controls. As a result, we generated four MAbs, three (1A2, 1A4, 1B9) against the polypeptide N51(L6)C46 monomer and one against the trimer, named 3A1. The four anti- N51(L6)C46 MAbs could bind N51(L6)C46 and N36(L6)C34 but not N36 or C34. The results of epitope analysis with competitive ELISA showed that the MAbs could recognize the similar epitopes, whereas the difference lie in that 3A1 could recognize the epitopes similar to NC-1s, whereas NC-1 could not recognize the epitopes similar to 3A1s. Taken together, these MAbs would be effective tools in selecting anti-HIV polypeptide and analyzing the characteristics of gp41 epitopes.
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Affiliation(s)
- Zheng Chen
- Department of Microbiology, State Key Laboratory of Cancer Biology & Institute of Digestive Diseases, Xijing Hospital, Xi'an, Shaanxi Province, China
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