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Wang Q, Su S, Xue J, Yu F, Pu J, Bi W, Xia S, Meng Y, Wang C, Yang W, Xu W, Zhu Y, Zheng Q, Qin C, Jiang S, Lu L. An amphipathic peptide targeting the gp41 cytoplasmic tail kills HIV-1 virions and infected cells. Sci Transl Med 2021; 12:12/546/eaaz2254. [PMID: 32493792 DOI: 10.1126/scitranslmed.aaz2254] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 04/28/2020] [Indexed: 12/26/2022]
Abstract
HIV-associated morbidity and mortality have markedly declined because of combinational antiretroviral therapy, but HIV readily mutates to develop drug resistance. Developing antivirals against previously undefined targets is essential to treat existing drug-resistant HIV strains. Some peptides derived from HIV-1 envelope glycoprotein (Env, gp120-gp41) have been shown to be effective in inhibiting HIV-1 infection. Therefore, we screened a peptide library from HIV-1 Env and identified a peptide from the cytoplasmic region, designated F9170, able to effectively inactivate HIV-1 virions and induce necrosis of HIV-1-infected cells, and reactivated latently infected cells. F9170 specifically targeted the conserved cytoplasmic tail of HIV-1 Env and effectively disrupted the integrity of the viral membrane. Short-term monoadministration of F9170 controlled viral loads to below the limit of detection in chronically SHIV-infected macaques. F9170 can enter the brain and lymph nodes, anatomic reservoirs for HIV latency. Therefore, F9170 shows promise as a drug candidate for HIV treatment.
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Affiliation(s)
- Qian Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Shan Su
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Jing Xue
- Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Beijing Key Laboratory for Animal Models of Emerging and Re-emerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing 100021, China
| | - Fei Yu
- College of Life and Science, Hebei Agricultural University, Baoding 071001, China
| | - Jing Pu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Wenwen Bi
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Shuai Xia
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Yu Meng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Cong Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Wenqian Yang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Wei Xu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Yun Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qinwen Zheng
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China
| | - Chuan Qin
- Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Beijing Key Laboratory for Animal Models of Emerging and Re-emerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing 100021, China.
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China. .,Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, 130 Dong An Rd., Xuhui District, Shanghai 200032, China.
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Xu W, Pu J, Su S, Hua C, Su X, Wang Q, Jiang S, Lu L. Revisiting the mechanism of enfuvirtide and designing an analog with improved fusion inhibitory activity by targeting triple sites in gp41. AIDS 2019; 33:1545-1555. [PMID: 30932963 DOI: 10.1097/qad.0000000000002208] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To revisit the mechanism of action of enfuvirtide (T20) and based on the newly defined mechanism, design an analogous peptide of T20 with improved antiviral activity. DESIGN We compared the inhibitory activity of T20 with that of T1144 on six-helix bundle (6HB) formation at different time after coculture of HIV type 1 (HIV-1) envelope (Env)-expressing Chinese hamster ovary (CHO-Env) cells and CD4-expressing MT-2 cells at 31.5 °C and with that of T20-SF, an analogous peptide of T20 with an additional tryptophan-rich motif, on hemolysis mediated by FP-P, which contains fusion peptide and fusion peptide (FP) proximal region (FPPR), and HIV-1 infection. METHODS Inhibitory activity of peptides on 6HB formation was tested in a temperature-controlled cell-cell fusion assay by flow cytometry using 6HB-specific mAb 2G8; on HIV-1 infection and fusion was assessed by p24 and cell-cell fusion assays. Interaction between different peptides or peptide and antibody was evaluated by ELISA. RESULTS T20 could inhibit 6HB formation at early, but not late, stage of HIV-1 fusion, whereas T1144 was effective at both stages. T20-SF is much more effective than T20 in binding to FP-P and inhibiting infection of HIV-1, including T20-resistant strains, and FP-P-mediated hemolysis. CONCLUSION Results suggest that T20 has a double-target mechanism, by which its N-terminal and C-terminal portions bind to N-terminal heptad repeat and FPPR, respectively. T20-SF designed based on this new mechanism exhibits significantly improved anti-HIV-1 activity because it targets the triple sites in gp41, including N-terminal heptad repeat, FPPR, and fusion peptide. Thus, this study provides clues for designing novel HIV fusion inhibitors with improved antiviral activity.
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Galatola R, Cruz A, Gómara MJ, Prat J, Alsina MA, Haro I, Pujol M. Surface behavior of peptides from E1 GBV-C protein: Interaction with anionic model membranes and importance in HIV-1 FP inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:392-407. [PMID: 25450346 DOI: 10.1016/j.bbamem.2014.10.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 11/25/2022]
Abstract
The interaction between a peptide sequence from GB virus C E1 protein (E1P8) and its structural analogs (E1P8-12), (E1P8-13), and (E1P8-21) with anionic lipid membranes (POPG vesicles and POPG, DPPG or DPPC/DPPG (2:1) monolayers) and their association with HIV-1 fusion peptide (HIV-1 FP) inhibition at the membrane level were studied using biophysical methods. All peptides showed surface activity but leakage experiments in vesicles as well as insertion kinetics in monolayers and lipid/peptide miscibility indicated a low level of interaction: neither E1P8 nor its analogs induced the release of vesicular content and the exclusion pressure values (πe) were clearly lower than the biological membrane pressure (24-30 mN m(-1)) and the HIV-1 FP (35 mN m(-1)). Miscibility was elucidated in terms of the additivity rule and excess free energy of mixing (GE). E1P8, E1P8-12 and E1P8-21 (but not E1P8-13) induced expansion of the POPG monolayer. The mixing process is not thermodynamically favored as the positive GE values indicate. To determine how E1 peptides interfere in the action of HIV-1 FP at the membrane level, mixed monolayers of HIV-1 FP/E1 peptides (2:1) and POPG were obtained. E1P8 and its derivative E1P8-21 showed the greatest HIV-1 FP inhibition. The LC-LE phase lipid behavior was morphologically examined via fluorescence microscopy (FM) and atomic force microscopy (AFM). Images revealed that the E1 peptides modify HIV-1 FP-lipid interaction. This fact may be attributed to a peptide/peptide interaction as indicated by AFM results. Finally, hemolysis assay demonstrated that E1 peptides inhibit HIV-1 FP activity.
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Affiliation(s)
- R Galatola
- Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain
| | - A Cruz
- Dept. de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain
| | - M J Gómara
- Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain
| | - J Prat
- Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, CSIC-Associated Unit: Peptides and Proteins: Physicochemical Studies, IN2UB Av. Joan XXIII s/n, 08028 Barcelona, Spain; Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain
| | - M A Alsina
- Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, CSIC-Associated Unit: Peptides and Proteins: Physicochemical Studies, IN2UB Av. Joan XXIII s/n, 08028 Barcelona, Spain
| | - I Haro
- Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain
| | - M Pujol
- Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, CSIC-Associated Unit: Peptides and Proteins: Physicochemical Studies, IN2UB Av. Joan XXIII s/n, 08028 Barcelona, Spain.
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A cyclic GB virus C derived peptide with anti-HIV-1 activity targets the fusion peptide of HIV-1. Eur J Med Chem 2014; 86:589-604. [DOI: 10.1016/j.ejmech.2014.09.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/03/2014] [Accepted: 09/06/2014] [Indexed: 12/23/2022]
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Pang W, Tam SC, Zheng YT. Current peptide HIV type-1 fusion inhibitors. Antivir Chem Chemother 2009; 20:1-18. [PMID: 19794228 DOI: 10.3851/imp1369] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
There are now 26 antiretroviral drugs and 6 fixed-dose combinations, including reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors and fusion (or entry) inhibitors, approved by the US Food and Drug Administration for clinical use. Although they are clinically effective when used in combination, none of the existing drugs are considered ideal because of toxic side effects and the ascendance of inducing drug-resistant mutants. Development of new antiviral agents is essential. In the past decades, there has been great progress in understanding the structure of HIV type-1 (HIV-1) gp41 and the mechanism of HIV-1 entry into host cells. This opened up a promising avenue for rationally designed agents to interfere with this process. A number of fusion inhibitors have been developed to block HIV-1 replication. Enfuvirtide (T20) was one of those approved for clinical use. This signalled a new era in AIDS therapeutics. It is a synthetic polypeptide with potent inhibitory activity against HIV-1 infection. However, it is sensitive to proteolytic digestion and resistant virus strains are easily induced with multiple clinical use. One of the directions in designing new fusion inhibitors is to overcome these shortages. In the past years, large numbers of promising fusion inhibitory peptides have emerged. The antiviral activities are more potent or they can act differently from that of T20. Some of these new compounds have great potential to be further developed as therapeutic agents. This article reviewed some recent developments of these peptides and the possible role in anti-HIV-1 therapy.
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Affiliation(s)
- Wei Pang
- Key Laboratory of Animal Models and Human Diseases Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
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Nieva JL, Nir S, Wilschut J. Destabilization and Fusion of Zwitterionic Large Unilamellar Lipid Vesicles Induced by a β-Type Structure of the Hiv-1 Fusion Peptide. J Liposome Res 2008. [DOI: 10.3109/08982109809035524] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Gordon LM, Nisthal A, Lee AB, Eskandari S, Ruchala P, Jung CL, Waring AJ, Mobley PW. Structural and functional properties of peptides based on the N-terminus of HIV-1 gp41 and the C-terminus of the amyloid-beta protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2127-37. [PMID: 18515070 DOI: 10.1016/j.bbamem.2008.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 04/07/2008] [Accepted: 05/06/2008] [Indexed: 11/30/2022]
Abstract
Given their high alanine and glycine levels, plaque formation, alpha-helix to beta-sheet interconversion and fusogenicity, FP (i.e., the N-terminal fusion peptide of HIV-1 gp41; 23 residues) and amyloids were proposed as belonging to the same protein superfamily. Here, we further test whether FP may exhibit 'amyloid-like' characteristics, by contrasting its structural and functional properties with those of Abeta(26-42), a 17-residue peptide from the C-terminus of the amyloid-beta protein responsible for Alzheimer's. FTIR spectroscopy, electron microscopy, light scattering and predicted amyloid structure aggregation (PASTA) indicated that aqueous FP and Abeta(26-42) formed similar networked beta-sheet fibrils, although the FP fibril interactions were weaker. FP and Abeta(26-42) both lysed and aggregated human erythrocytes, with the hemolysis-onsets correlated with the conversion of alpha-helix to beta-sheet for each peptide in liposomes. Congo red (CR), a marker of amyloid plaques in situ, similarly inhibited either FP- or Abeta(26-42)-induced hemolysis, and surface plasmon resonance indicated that this may be due to direct CR-peptide binding. These findings suggest that membrane-bound beta-sheets of FP may contribute to the cytopathicity of HIV in vivo through an amyloid-type mechanism, and support the classification of HIV-1 FP as an 'amyloid homolog' (or 'amylog').
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Affiliation(s)
- Larry M Gordon
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
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Gabrys CM, Weliky DP. Chemical shift assignment and structural plasticity of a HIV fusion peptide derivative in dodecylphosphocholine micelles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:3225-34. [PMID: 17935693 DOI: 10.1016/j.bbamem.2007.07.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 07/31/2007] [Accepted: 07/31/2007] [Indexed: 10/22/2022]
Abstract
A "HFPK3" peptide containing the 23 residues of the human immunodeficiency virus (HIV) fusion peptide (HFP) plus three non-native C-terminal lysines was studied in dodecylphosphocholine (DPC) micelles with 2D 1H NMR spectroscopy. The HFP is at the N-terminus of the gp41 fusion protein and plays an important role in fusing viral and target cell membranes which is a critical step in viral infection. Unlike HFP, HFPK3 is monomeric in detergent-free buffered aqueous solution which may be a useful property for functional and structural studies. H alpha chemical shifts indicated that DPC-associated HFPK3 was predominantly helical from I4 to L12. In addition to the highest-intensity crosspeaks used for the first chemical shift assignment (denoted I), there were additional crosspeaks whose intensities were approximately 10% of those used for assignment I. A second assignment (II) for residues G5 to L12 as well as a few other residues was derived from these lower-intensity crosspeaks. Relative to the I shifts, the II shifts were different by 0.01-0.23 ppm with the largest differences observed for HN. Comparison of the shifts of DPC-associated HFPK3 with those of detergent-associated HFP and HFP derivatives provided information about peptide structures and locations in micelles.
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Affiliation(s)
- Charles M Gabrys
- Department of Chemistry, Michigan State University, East Lansing, MI 48824-1320, USA
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Münch J, Ständker L, Adermann K, Schulz A, Schindler M, Chinnadurai R, Pöhlmann S, Chaipan C, Biet T, Peters T, Meyer B, Wilhelm D, Lu H, Jing W, Jiang S, Forssmann WG, Kirchhoff F. Discovery and Optimization of a Natural HIV-1 Entry Inhibitor Targeting the gp41 Fusion Peptide. Cell 2007; 129:263-75. [PMID: 17448989 DOI: 10.1016/j.cell.2007.02.042] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 12/12/2006] [Accepted: 02/08/2007] [Indexed: 11/15/2022]
Abstract
A variety of molecules in human blood have been implicated in the inhibition of HIV-1. However, it remained elusive which circulating natural compounds are most effective in controlling viral replication in vivo. To identify natural HIV-1 inhibitors we screened a comprehensive peptide library generated from human hemofiltrate. The most potent fraction contained a 20-residue peptide, designated VIRUS-INHIBITORY PEPTIDE (VIRIP), corresponding to the C-proximal region of alpha1-antitrypsin, the most abundant circulating serine protease inhibitor. We found that VIRIP inhibits a wide variety of HIV-1 strains including those resistant to current antiretroviral drugs. Further analysis demonstrated that VIRIP blocks HIV-1 entry by interacting with the gp41 fusion peptide and showed that a few amino acid changes increase its antiretroviral potency by two orders of magnitude. Thus, as a highly specific natural inhibitor of the HIV-1 gp41 fusion peptide, VIRIP may lead to the development of another class of antiretroviral drugs.
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Affiliation(s)
- Jan Münch
- Institute of Virology, University of Ulm, 89081 Ulm, Germany
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Mobley PW, Barry JA, Waring AJ, Sherman MA, Gordon LM. Membrane perturbing actions of HIV type 1 glycoprotein 41 domains are inhibited by helical C-peptides. AIDS Res Hum Retroviruses 2007; 23:224-42. [PMID: 17331029 DOI: 10.1089/aid.2006.0046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To study the membrane actions of various domains of HIV-1 glycoprotein 41,000 (gp41), synthetic peptides were prepared corresponding to the N-terminal fusion region (FP; gp41 residues 519-541), the nearby N-leucine zipper domain (N-peptides; DP-107; gp41 residues 560-597), the C-leucine zipper domain (C-peptides; DP-178; gp41 residues 645-680), and the viral envelope adjacent domain that partially overlaps DP-178 (Pre-TM; gp41 residues 671-690). With erythrocytes, FP, DP-107, and Pre-TM induced hemolysis and cell aggregation; the order for hemolytic activity was Pre-TM > FP > DP-107, but each was equally effective in aggregating cells at the highest peptide concentrations tested. DP-178 produced neither hemolysis nor aggregation, but efficiently reduced FP-, DP-107-, and Pre-TM-induced membrane actions. Fourier transform infrared spectroscopy indicated that the membrane perturbations of Pre-TM, as well as the ability of DP-178 to block membrane activities of other gp41 domains, are dependent on Pre-TM and DP-178 each maintaining helical conformations and tryptophans at residues 673, 677, and 679. These results suggest that the corresponding N-terminal fusion, N-leucine zipper, and viral membrane-adjacent regions of HIV-1 gp41 may similarly promote key membrane perturbations underlying the merging of the viral envelope with the cell surface. Further, the antiviral mechanism of exogenous DP-178 (clinically approved enfuvirtide) may be partially explained by its coordinate inhibition of the fusogenic actions of the FP, DP-107, and Pre-TM regions of gp41.
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Affiliation(s)
- Patrick W Mobley
- Chemistry Department, California State Polytechnic University, Pomona, CA 91768, USA
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Mavoungou D, Poaty-Mavoungou V, Akoume MY, Ongali B, Mavoungou E. Inhibition of human immunodeficiency virus type-1 (HIV-1) glycoprotein-mediated cell-cell fusion by immunor (IM28). Virol J 2005; 2:9. [PMID: 15707492 PMCID: PMC552330 DOI: 10.1186/1743-422x-2-9] [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] [Received: 12/22/2004] [Accepted: 02/11/2005] [Indexed: 11/26/2022] Open
Abstract
Background Immunor (IM28), an analog of dehydroepiandrosterone (DHEA), inhibits human immunodeficiency virus type-1 (HIV-1) by inhibiting reverse transcriptase. We assessed the ability of IM28 to inhibit the cell-cell fusion mediated by HIV envelope glycoprotein in an in vitro system. For this purpose, we co-cultured TF228.1.16, a T-cell line expressing stably HIV-1 glycoprotein envelopes, with an equal number of 293/CD4+, another T cell line expressing CD4, and with the SupT1 cell line with or without IM28. Results In the absence of IM28, TF228.1.16 fused with 293/CD4+, inducing numerous large syncytia. Syncytia appeared more rapidly when TF228.1.16 was co-cultured with SupT1 cells than when it was co-cultured with the 293/CD4+ cell line. IM28 (1.6 – 45 μg/ml) completely inhibits cell-cell fusion. IM28 also prevented the development of new syncytia in infected cells and protected naive SupT1 cells from HIV-1 infection. Evaluation of 50% inhibitory dose (IC50) of IM28 revealed a decrease in HIV-1 replication with an IC50 of 22 mM and 50% cytotoxicity dose (CC50) as determined on MT2 cells was 75 mM giving a selectivity index of 3.4 Conclusions These findings suggest that IM28 exerts an inhibitory action on the env proteins that mediate cell-cell fusion between infected and healthy cells. They also suggest that IM28 interferes with biochemical processes to stop the progression of existing syncytia. This property may lead to the development of a new class of therapeutic drug.
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Affiliation(s)
| | - Virginie Poaty-Mavoungou
- Centre de recherche sur les pathologies hormonales, Libreville, Gabon
- Department of Parasitology, Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Marie-Yvonne Akoume
- Département de Pharmacologie, Université de Montréal, Montréal, Québec, Canada
| | - Brice Ongali
- Département de Physiologie, Université de Montréal, Montréal, Québec, Canada
| | - Elie Mavoungou
- Centre de recherche sur les pathologies hormonales, Libreville, Gabon
- Department of Parasitology, Institute for Tropical Medicine, University of Tübingen, Tübingen, Germany
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Gordon LM, Mobley PW, Lee W, Eskandari S, Kaznessis YN, Sherman MA, Waring AJ. Conformational mapping of the N-terminal peptide of HIV-1 gp41 in lipid detergent and aqueous environments using 13C-enhanced Fourier transform infrared spectroscopy. Protein Sci 2004; 13:1012-30. [PMID: 15044732 PMCID: PMC2280061 DOI: 10.1110/ps.03407704] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Revised: 11/26/2004] [Accepted: 11/28/2004] [Indexed: 10/26/2022]
Abstract
The N-terminal domain of HIV-1 glycoprotein 41,000 (gp41) participates in viral fusion processes. Here, we use physical and computational methodologies to examine the secondary structure of a peptide based on the N terminus (FP; residues 1-23) in aqueous and detergent environments. (12)C-Fourier transform infrared (FTIR) spectroscopy indicated greater alpha-helix for FP in lipid-detergent sodium dodecyl sulfate (SDS) and aqueous phosphate-buffered saline (PBS) than in only PBS. (12)C-FTIR spectra also showed disordered FP conformations in these two environments, along with substantial beta-structure for FP alone in PBS. In experiments that map conformations to specific residues, isotope-enhanced FTIR spectroscopy was performed using FP peptides labeled with (13)C-carbonyl. (13)C-FTIR results on FP in SDS at low peptide loading indicated alpha-helix (residues 5 to 16) and disordered conformations (residues 1-4). Because earlier (13)C-FTIR analysis of FP in lipid bilayers demonstrated alpha-helix for residues 1-16 at low peptide loading, the FP structure in SDS micelles only approximates that found for FP with membranes. Molecular dynamics simulations of FP in an explicit SDS micelle indicate that the fraying of the first three to four residues may be due to the FP helix moving to one end of the micelle. In PBS alone, however, electron microscopy of FP showed large fibrils, while (13)C-FTIR spectra demonstrated antiparallel beta-sheet for FP (residues 1-12), analogous to that reported for amyloid peptides. Because FP and amyloid peptides each exhibit plaque formation, alpha-helix to beta-sheet interconversion, and membrane fusion activity, amyloid and N-terminal gp41 peptides may belong to the same superfamily of proteins.
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Affiliation(s)
- Larry M Gordon
- REI at Harbor-UCLA Medical Center, 124 West Carson Street, Bldg. F5 South, Torrance, CA 90502-2064, USA.
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Nieva JL, Agirre A. Are fusion peptides a good model to study viral cell fusion? BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1614:104-15. [PMID: 12873771 DOI: 10.1016/s0005-2736(03)00168-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fusion peptides are hydrophobic and conserved sequences located within glycoprotein ectodomains that protrude from the virion surface. Direct participation of fusion peptides in the viral membrane fusion phenomenon has been inferred from genetic analyses showing that even a single residue substitution or a deletion within these sequences may completely block the process. However, the specific fusion peptide activities associated to the multi-step fusion mechanism are not well defined. Based on the assumption that fusion peptides are transferred into target membranes, biophysical methodologies have been applied to study integration into model membranes of synthetic fragments representing functional and non-functional sequences. From these studies, it is inferred that, following insertion, functional sequences generate target membrane perturbations and adopt specific structural arrangements within. Further characterization of these artificial systems may help in understanding the molecular processes that bring initial bilayer destabilizations to the eventual opening of a fusion pore.
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Affiliation(s)
- José L Nieva
- Unidad de Biofísica (CSIC-UPV/EHU) and Departamento de Bioquímica, Universidad del País Vasco, Aptdo. 644, 48080, Bilbao, Spain.
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Gordon LM, Mobley PW, Pilpa R, Sherman MA, Waring AJ. Conformational mapping of the N-terminal peptide of HIV-1 gp41 in membrane environments using (13)C-enhanced Fourier transform infrared spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1559:96-120. [PMID: 11853678 DOI: 10.1016/s0005-2736(01)00443-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The N-terminal domain of HIV-1 glycoprotein 41000 (FP; residues 1--23; AVGIGALFLGFLGAAGSTMGARSCONH(2)) participates in fusion processes underlying virus--cell infection. Here, we use physical techniques to study the secondary conformation of synthetic FP in aqueous, structure-promoting, lipid and biomembrane environments. Circular dichroism and conventional, (12)C-Fourier transform infrared (FTIR) spectroscopy indicated the following alpha-helical levels for FP in 1-palmitoyl-2-oleoylphosphatidylglycerol (POPG) liposomes-hexafluoroisopropanol (HFIP)>trifluoroethanol (TFE)>phosphate-buffered saline (PBS). (12)C-FTIR spectra also showed disordered FP structures in these environments, along with substantial beta-structures for FP in TFE or PBS. In further experiments designed to map secondary conformations to specific residues, isotope-enhanced FTIR spectroscopy was performed using a suite of FP peptides labeled with (13)C-carbonyl at multiple sites. Combining these (13)C-enhanced FTIR results with molecular simulations indicated the following model for FP in HFIP: alpha-helix (residues 3-16) and random and beta-structures (residues 1-2 and residues 17-23). Additional (13)C-FTIR analysis indicated a similar conformation for FP in POPG at low peptide loading, except that the alpha-helix extends over residues 1-16. At low peptide loading in either human erythrocyte ghosts or lipid extracts from ghosts, (13)C-FTIR spectroscopy showed alpha-helical conformations for the central core of FP (residues 5-15); on the other hand, at high peptide loading in ghosts or lipid extracts, the central core of FP assumed an antiparallel beta-structure. FP at low loading in ghosts probably inserts deeply as an alpha-helix into the hydrophobic membrane bilayer, while at higher loading FP primarily associates with ghosts as an aqueous-accessible, beta-sheet. In future studies, (13)C-FTIR spectroscopy may yield residue-specific conformations for other membrane-bound proteins or peptides, which have been difficult to analyze with more standard methodologies.
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Affiliation(s)
- Larry M Gordon
- Department of Pediatrics, Harbor-University of California at Los Angeles Medical Center, 90502-2064, USA.
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15
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Dimitrov AS, Xiao X, Dimitrov DS, Blumenthal R. Early intermediates in HIV-1 envelope glycoprotein-mediated fusion triggered by CD4 and co-receptor complexes. J Biol Chem 2001; 276:30335-41. [PMID: 11397808 DOI: 10.1074/jbc.m103788200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An early step in the process of HIV-1 entry into target cells is the activation of its envelope glycoprotein (GP120-GP41) to a fusogenic state upon binding to target cell CD4 and cognate co-receptor. Incubation of human immunodeficiency virus (HIV)-1 Env-expressing cells with an excess of CD4 and co-recepeptor-bearing target cells resulted in an influx of an impermeant nucleic acid-staining fluorescent dye into the Env-expressing cells. The dye influx occurred concomitant with cell fusion. No influx of dye into target cells was observed if they were incubated with an excess of Env-expressing cells. The permeabilization of Env-expressing cells was also triggered by CD4.co-receptor complexes attached to Protein G-Sepharose beads in the absence of target cells. The CD4 and co-receptor-induced permeabilization of Env-expressing cells occurred with the same specificity with respect to co-receptor usage as cell fusion. Natural ligands for the co-receptors and C-terminal GP41 peptide inhibitors of HIV-1 fusion blocked this effect. Our results indicate that the process of HIV-1 Env-mediated fusion is initiated by the destabilization of HIV-1 Env-expressing membranes. Further elucidation of these early intermediates may help identify and develop potential inhibitors of HIV-1 entry into cells.
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Affiliation(s)
- A S Dimitrov
- Laboratory of Experimental and Computational Biology, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702, USA
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16
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Mobley PW, Pilpa R, Brown C, Waring AJ, Gordon LM. Membrane-perturbing domains of HIV type 1 glycoprotein 41. AIDS Res Hum Retroviruses 2001; 17:311-27. [PMID: 11242518 DOI: 10.1089/08892220150503681] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Structural and functional studies were performed to assess the membrane actions of peptides based on HIV-1 glycoprotein 41,000 (gp41). Previous site-directed mutagenesis of gp41 has shown that amino acid changes in either the N-terminal fusion or N-leucine zipper region depressed viral infection and syncytium formation, while modifications in the C-leucine zipper domain both increased and decreased HIV fusion. Here, synthetic peptides were prepared corresponding to the N-terminal fusion region (FP-I; gp41 residues 519-541), the nearby N-leucine zipper domain (DP-107; gp41 residues 560-597), and the C-leucine zipper domain (DP-178; gp41 residues 645-680). With erythrocytes, FP-I or DP-107 induced dose-dependent hemolysis and promoted cell aggregation; FP-I was more hemolytic than DP-107, but each was equally effective in aggregating cells. DP-178 produced neither hemolysis nor aggregation, but blocked either FP-I- or DP-107-induced hemolysis and aggregation. Combined with previous nuclear magnetic resonance and Fourier transform infrared spectroscopic results, circular dichroism (CD) spectroscopy showed that the alpha-helicity for these peptides in solution decreased in the order: DP-107 >> DP-178 > FP-I. CD analysis also indicated binding of DP-178 to either DP-107 or FP-I. Consequently, DP-178 may inhibit the membrane actions mediated by either FP-I or DP-107 through direct peptide interactions in solution. These peptide results suggest that the corresponding N-terminal fusion and N-leucine zipper regions participate in HIV infection, by promoting membrane perturbations underlying the merging of the viral envelope with the cell surface. Further, the C-leucine zipper domain in "prefusion" HIV may inhibit these membrane activities by interacting with the N-terminal fusion and N-leucine zipper domains in unactivated gp41. Last, exogenous DP-178 may bind to the N-terminal and N-leucine zipper domains of gp41 that become exposed on HIV stimulation, thereby preventing the fusogenic actions of these gp41 regions leading to infection.
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Affiliation(s)
- P W Mobley
- Chemistry Department, California State Polytechnic University, Pomona 91768, USA
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17
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Interaction of HIV-1 fusion peptide and its mutant with lipid membrane. CHINESE SCIENCE BULLETIN-CHINESE 2000. [DOI: 10.1007/bf02887410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Schwarz G, Taylor SE. Polymorphism and interactions of a viral fusion peptide in a compressed lipid monolayer. Biophys J 1999; 76:3167-75. [PMID: 10354441 PMCID: PMC1300285 DOI: 10.1016/s0006-3495(99)77468-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
With a view toward possible new insights into viral fusion mechanisms, we have investigated the HIV-1 gp41 fusion peptide in a monomolecular film of the biomembrane lipid palmitoyloleoylphosphatidylcholine. Its surface activity at an air/water interface was measured under equilibrium conditions, using the conventional Langmuir trough technique. Through a novel thermodynamic analysis, the partial molecular area of the peptide in the lipid moiety could be determined as a function of the lateral pressure and the interfacial peptide/lipid ratio. This indicates an orientation of the peptide backbone parallel to the lipid hydrocarbon tails. The molecular area decreases significantly upon monolayer compression, suggesting a conformational transition from a somewhat compact configuration to a more extended, presumably beta-strand structure when a lipid packing density is approached that is generally believed to mimic the physical state of a biological membrane. Up to a lateral pressure of approximately 15 mN/m, practically all peptide inserts into the lipid monolayer. At higher compression a distinct partitioning into the aqueous subphase is observed. Under these conditions the data also reflect a strong aggregation of the lipid-associated peptide. Beyond a critical peptide/lipid ratio, the peptide's area requirement was found to become substantially enhanced, possibly because of the formation of water-filled pores.
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Affiliation(s)
- G Schwarz
- Department of Biophysical Chemistry, Biocenter of the University, University of Basel, CH-4056 Basel, Switzerland.
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19
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Mobley PW, Waring AJ, Sherman MA, Gordon LM. Membrane interactions of the synthetic N-terminal peptide of HIV-1 gp41 and its structural analogs. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1418:1-18. [PMID: 10209206 DOI: 10.1016/s0005-2736(99)00014-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Structural and functional studies assessed the membrane actions of the N terminus of HIV-1 glycoprotein 41000 (gp41). Earlier site-directed mutagenesis has shown that key amino acid changes in this gp41 domain inhibit viral infection and syncytia formation. Here, a synthetic peptide corresponding to the N terminus of gp41 (FP; 23 residues, 519-541), and also FP analogs (FP520V/E with Val-->Glu at residue 520; FP527L/R with Leu-->Arg at 527; FP529F/Y with Phe-->Tyr at 529; and FPCLP1 with FP truncated at 525) incorporating these modifications were prepared. When added to human erythrocytes at physiologic pH, the lytic and aggregating activities of the FP analogs were much reduced over those with the wild-type FP. With resealed human erythrocyte ghosts, the lipid-mixing activities of the FP analogs were also substantially depressed over that with the wild-type FP. Combined with results from earlier studies, theoretical calculations using hydrophobic moment plot analysis and physical experiments using circular dichroism and Fourier transform infrared spectroscopy indicate that the diminished lysis and fusion noted for FP analogs may be due to altered peptide-membrane lipid interactions. These data confirm that the N-terminal gp41 domain plays critical roles in the cytolysis and fusion underlying HIV-cell infection.
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Affiliation(s)
- P W Mobley
- Chemistry Department, California State Polytechnic University, Pomona, Pomona, CA, USA
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20
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Silburn KA, McPhee DA, Maerz AL, Poumbourios P, Whittaker RG, Kirkpatrick A, Reilly WG, Manthey MK, Curtain CC. Efficacy of fusion peptide homologs in blocking cell lysis and HIV-induced fusion. AIDS Res Hum Retroviruses 1998; 14:385-92. [PMID: 9546797 DOI: 10.1089/aid.1998.14.385] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Contrary to earlier reports, we have found that tri- and hexapeptides analogous or homologous with segments of the 23-residue N-terminal fusion sequence (FS) of the viral transmembrane glycoprotein gp41 (residues 517-539) did not significantly inhibit HIV-1-induced syncytium formation, using an uninfected cell-infected cell fusion assay. In contrast, we found that the high molecular weight apolipoprotein A-1 and a 23-residue analog of the FS, with the phenylalanine residues at positions 524 and 527 replaced with alanine residues, were effective inhibitors. Although the tripeptides were ineffective as inhibitors of syncytium formation, we found a number of them inhibited red cell lysis induced by the synthetic peptide AVGIGALFLGFLGAAGSTMGARS (based on the HIV-1 gp41 FS). This effect was also seen with apolipoprotein A-1. The Ala524,527 analog of the fusion sequence could not be tested in this system because it was hemolytic. We concluded that the smaller peptides were effective inhibitors of hemolysis because they interfered with pore formation by the fusion sequence peptide, either by disrupting the pores or by preventing the peptide from adopting the alpha-helical conformation found in the pores. On the other hand, membrane fusion, which is a prelude to syncytium formation, has been shown to require the fusion sequence in the beta-strand conformation. We argue that small peptides would be unable to block interaction between such strands, although larger molecules, such as apolipoprotein A-1 and the Ala524,527 analog, would be able to do so and thus inhibit fusion. It seems, therefore, that a successful drug directed against the FS-cell membrane interaction stage of syncytium formation would need to be of relatively high molecular weight and complexity.
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Affiliation(s)
- K A Silburn
- AIDS Cellular Biology Unit, Macfarlane Burnet Centre for Medical Research, Fairfield, Victoria, Australia
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21
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Comardelle AM, Norris CH, Plymale DR, Gatti PJ, Choi B, Fermin CD, Haislip AM, Tencza SB, Mietzner TA, Montelaro RC, Garry RF. A synthetic peptide corresponding to the carboxy terminus of human immunodeficiency virus type 1 transmembrane glycoprotein induces alterations in the ionic permeability of Xenopus laevis oocytes. AIDS Res Hum Retroviruses 1997; 13:1525-32. [PMID: 9390752 DOI: 10.1089/aid.1997.13.1525] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The carboxy-terminal 29 amino acids of the human immunodeficiency virus type 1 transmembrane glycoprotein (HIV-1 TM) are referred to as lentivirus lytic peptide 1 (LLP-1). Synthetic peptides corresponding to LLP-1 have been shown to induce cytolysis and to alter the permeability of cultured cells to various small molecules. To address the mechanisms by which LLP-1 induces cytolysis and membrane permeability changes, various concentrations of LLP-1 were incubated with Xenopus laevis oocytes, and two-electrode, voltage-clamp recording measurements were performed. LLP-1 at concentrations of 75 nM and above induced dramatic alterations in the resting membrane potential and ionic permeability of Xenopus oocytes. These concentrations of LLP-1 appeared to induce a major disruption of plasma membrane electrophysiological integrity. In contrast, concentrations of LLP-1 of 20-50 nM induced changes in membrane ionic permeability that mimic changes induced by compounds, such as the bee venom peptide melittin, that are known to form channel-like structures in biological membranes at sublytic concentrations. An analog of LLP-1 with greatly reduced cytolytic activity failed to alter the electrophysiological properties of Xenopus oocytes. Thus, by altering plasma membrane ionic permeability, the carboxy terminus of TM may contribute to cytolysis of HIV-1-infected CD4+ cells.
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Affiliation(s)
- A M Comardelle
- Graduate Program in Molecular and Cellular Biology, Tulane University, New Orleans, Louisiana 70112, USA
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22
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Pereira FB, Goñi FM, Nieva JL. Membrane fusion induced by the HIV type 1 fusion peptide: modulation by factors affecting glycoprotein 41 activity and potential anti-HIV compounds. AIDS Res Hum Retroviruses 1997; 13:1203-11. [PMID: 9310287 DOI: 10.1089/aid.1997.13.1203] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Peptides representing a sequence of 23 amino acid residues at the N terminus of human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp41 bind and subsequently induce fusion of large unilamellar vesicles (LUV), an activity presumably related to gp41 function in viral infection. These in vitro effects can be modulated by several factors that are known to affect HIV-1 infectivity and gp41-mediated virus-cell fusion. Peptide-induced membrane fusion but not peptide binding can be inhibited by two factors known to block gp41 activity: a polar amino acid substitution V --> E in position 2 and the presence of the N-terminal hexapeptide of gp41 in addition to the parent sequence. Whereas inclusion of the alternative gp120 receptor galactosylceramide in membranes has virtually no effect, membrane cholesterol stimulates fusion activity. In view of its putative physiological relevance, we have used the fusion activity of the peptides as a tool to evaluate the inhibitory effect of antivirals that might target this sequence. We describe three dissimilar effects: Amphotericin B inhibits in a cholesterol-independent way peptide-induced fusion but not binding, human serum albumin inhibits binding and consequently fusion, and dextran sulfate (M(r) 5000) does not affect either binding or fusion.
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Affiliation(s)
- F B Pereira
- Department of Biochemistry and Molecular Biology (Biomembrane Laboratory-CSIC), University of the Basque Country, Bilbao, Spain
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23
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Curtain CC, Lowe MG, Arunagiri CK, Mobley PW, Macreadie IG, Azad AA. Cytotoxic activity of the amino-terminal region of HIV type 1 Nef protein. AIDS Res Hum Retroviruses 1997; 13:1213-20. [PMID: 9310288 DOI: 10.1089/aid.1997.13.1213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Myristoylated 21- and 25-residue N-terminal peptides of the Nef protein of HIV-1 lysed human erythrocytes and were cytotoxic toward a human CD4+ T cell line, CEM, and primary human peripheral blood mononuclear cells (PBMCs). The corresponding nonmyristoylated N-terminal peptides were only very weakly hemolytic and cytotoxic. A myristoylated peptide consisting of residues 31-50 of Nef was neither hemolytic nor cytotoxic. Alteration of the tryptophan residue at position 13 to a serine did not change the hemolytic and cytotoxic activity. Studies of the ultraviolet fluorescence of the tryptophan at position 5 in the peptide, using an artificial membrane system and fluorescence-quenching agents that inserted into the bilayer at different levels, suggested that myristoylation results in this residue being brought into contact with the upper hydrocarbon region of the lipid bilayer of the cell membrane. This tryptophan is flanked by a number of polar residues that would maintain it in this position, resulting in a considerable increase in disorder in the upper regions of the lipid bilayer, leading to its destabilization and to lysis. The cytotoxic activity of the myristoylated Nef fragments may, in part, explain the killing and deletion of cells, especially in lymphoid tissues, during HIV infection.
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Affiliation(s)
- C C Curtain
- Biomolecular Research Institute, Parkville Victoria, Australia.
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24
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Chang DK, Cheng SF, Chien WJ. The amino-terminal fusion domain peptide of human immunodeficiency virus type 1 gp41 inserts into the sodium dodecyl sulfate micelle primarily as a helix with a conserved glycine at the micelle-water interface. J Virol 1997; 71:6593-602. [PMID: 9261381 PMCID: PMC191937 DOI: 10.1128/jvi.71.9.6593-6602.1997] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A peptide based on the N-terminal fusion domain of gp41 of human immunodeficiency virus type 1 (HIV-1) and its tryptophan analog were synthesized to examine the secondary structure in the micellar environment. Nuclear magnetic resonance (NMR), circular dichroism and electron paramagnetic resonance experiments indicated that the gp41 fusion peptide inserted into the micelle primarily as a helix (59%), with substantial beta-structure (26.7%). Deep penetration of the peptide into the apolar hydrocarbon core was supported by the results of fluorescence experiments in which the tryptophan analog exhibited a blue shift of about 30 nm in the presence of a sodium dodecyl sulfate micelle, in 1,2-dimyristoyl-rac-glycero-3-phosphocholine, and in 1,2-dipalmitoyl-sn-glycero-3-phospho-L-serine vesicular solutions. The results of spin label-attenuated 1H resonance experiments show that the region C-terminal to G16, which contains a turn structure, exhibited substantial interaction with the micelle, suggesting that it lies on the surface of micelle. Molecular simulation based on data from NMR experiments revealed a flexible hinge at residues 15 and 16 (alanine and glycine, respectively) from the N terminus of the peptide located at the micelle-solution interface. The highly conserved A15-G16 dipeptide may play a role in the function of fusion domain of HIV-1 envelope glycoprotein.
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Affiliation(s)
- D K Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan, Republic of China.
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25
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Taylor SE, Schwarz G. The molecular area characteristics of the HIV-1 gp41-fusion peptide at the air/water interface. Effect of pH. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1326:257-64. [PMID: 9218556 DOI: 10.1016/s0005-2736(97)00029-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The putative fusion peptide of HIV-1 is a highly surface active substance. Relevant measurements with the Langmuir monolayer technique have been carried out for a broad range of the pH in the aqueous subphase. The data are processed towards a quantitative analysis of the partitioning equilibrium between the interfacial and aqueous moieties. Our results reveal a pronounced decrease of the surface area per peptide molecule upon monolayer compression. This phenomenon could be interpreted in terms of an orientational transition experienced by an alpha-helical peptide structure. The area requirements at any fixed lateral pressure pass through a distinct minimum at a pH of 5.5 (+/-0.5). Such an apparent isoelectric point was confirmed by isoelectric focusing of peptide aggregates. Accordingly a drastic drop of the pK-values of the two basic amino acid residues in comparison with an aqueous medium is indicated. It can be readily explained based on an inherent decrease of the effective dielectric constant. The observed low pH in favor of an enhanced surface affinity of the peptide may be a significant factor concerning its function as a fusion promoting agent.
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Affiliation(s)
- S E Taylor
- Department of Biophysical Chemistry, Biocenter of the University, Basel, Switzerland
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26
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Mobley PW, Lee HF, Curtain CC, Kirkpatrick A, Waring AJ, Gordon LM. The amino-terminal peptide of HIV-1 glycoprotein 41 fuses human erythrocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1271:304-14. [PMID: 7605797 DOI: 10.1016/0925-4439(95)00048-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The ability of synthetic peptides based on the amino-terminus of HIV-1 glycoprotein 41,000 (gp41) to fuse human erythrocytes was investigated. Previous site-directed mutagenesis studies have shown an important role for the N-terminal gp41 domain in HIV-fusion, in which replacement of hydrophobic amino acids with polar residues inhibits viral infection and syncytia formation. Here, a synthetic peptide (FP; 23 amino acid residues 519-541) corresponding to the N-terminus of HIV-1 gp41, and also a FP analog (FP526L/R) with Arg replacing Leu-526, were prepared with solid phase techniques. The lipid mixing and leakage of resealed ghosts triggered by these peptides were examined with fluorescence quenching techniques. Peptide-induced aggregation of human erythrocytes was studied using Coulter counter sizing and scanning electron microscopy (SEM). Using resealed erythrocyte ghosts at physiologic pH, FP induces rapid lipid mixing between red cell membranes at doses previously shown to hemolyze intact cells. FP also causes leakage from resealed ghosts, and promotes the formation of multicelled aggregates with whole erythrocytes. Contrarily, similar FP526L/R concentrations did not induce red cell lysis, lipid mixing, leakage or aggregation. Since the fusogenic potency of FP and FP526L/R parallels earlier gp41 mutagenesis studies showing that substitution of Arg for Leu-526 blocks fusion activity, these data suggest that the N-terminal gp41 domain in intact HIV participates in fusion.
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Affiliation(s)
- P W Mobley
- Chemistry Department, California State Polytechnic University, Pomona, USA
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27
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Gordon LM, Waring AJ, Curtain CC, Kirkpatrick A, Leung C, Faull K, Mobley PW. Antivirals that target the amino-terminal domain of HIV type 1 glycoprotein 41. AIDS Res Hum Retroviruses 1995; 11:677-86. [PMID: 7576927 DOI: 10.1089/aid.1995.11.677] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Functional and structural studies were made to assess whether a class of antiviral agents targets the N-terminal domain of the glycoprotein 41,000 (gp41) of human immunodeficiency virus type 1 (HIV-1). Previous experiments have shown that the amino-terminal peptide (FP-I; 23 amino acids, residues 519-541) of HIV-1 gp41 is cytolytic to both human erythrocytes (non-CD4+ cells) and Hut-78 cells (CD4+ lymphocytes). Accordingly, FP-I-induced hemolysis may be used as a surrogate assay for evaluating the role of the N-terminal gp41 domain in HIV-cell interactions. Here, we studied the blocking of FP-I-induced lysis of erythrocytes by the following anti-HIV agents: (1) IgG [i.e., anti-(518-541) IgG] raised to an immunoconjugate of Arg-FP-I, (2) apolipoprotein A-1 (apo A-1) and a peptide based on apo A-1, (3) dextran sulfate, (4) gp41 peptide (residues 637-666), and (5) anionic human serum albumins. Dose-response curves indicated that their relative potency in inhibiting FP-I-induced hemolysis was approximately correlated with their previously reported anti-HIV activity. Electron spin resonance (ESR) studies showed that FP-I spin labeled at the N-terminal alanine binds to anti-(518-541) IgG, dextran sulfate, and anionic albumins. The high in vitro antiviral activity and low cytotoxicity of these agents suggest that blocking membrane-FP-I interactions offers a novel approach for AIDS therapy or prophylaxis.
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Affiliation(s)
- L M Gordon
- Department of Pediatrics, Drew University-King Medical Center/UCLA 90059, USA
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28
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Pereira FB, Goñi FM, Nieva JL. Liposome destabilization induced by the HIV-1 fusion peptide effect of a single amino acid substitution. FEBS Lett 1995; 362:243-6. [PMID: 7720880 DOI: 10.1016/0014-5793(95)00257-a] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The 23-residue synthetic peptide representing the N-terminus of HIV-1 gp41 is known to induce either leakage or fusion of lipid vesicles depending on the experimental conditions. In this paper we report that a polar amino acid substitution V-->E at position 2, known to block gp41 activity in vivo, makes the peptide unable to destabilize and/or fuse membranes. Moreover this variant, unlike the parent peptide, is never found in the membrane-associated beta conformation.
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Affiliation(s)
- F B Pereira
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Bilbao, Spain
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29
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Abstract
A considerable part of important biological processes is governed by the noncovalent association of peptides and proteins. Various types of intermolecular forces may be involved in the formation of these molecular assemblies. This review gives a brief account of the physicochemical bases of interactive forces, with special emphasis on their impact on various peptide-protein interactions; summarizes the newest biochemical and biophysical methods for the study of such interactions; and discusses the role of various hydrophilic and hydrophobic forces in peptide-protein interactions in various fields of life sciences, such as immunology, enzymology, receptor binding, and toxicology.
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Affiliation(s)
- T Cserháti
- Central Research Institute for Chemistry, Hungarian Academy of Sciences, Budapest
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30
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Curtain CC, Separovic F, Rivett D, Kirkpatrick A, Waring AJ, Gordon LM, Azad AA. Fusogenic activity of amino-terminal region of HIV type 1 Nef protein. AIDS Res Hum Retroviruses 1994; 10:1231-40. [PMID: 7848681 DOI: 10.1089/aid.1994.10.1231] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have studied two isoforms of Nef, Nef-27 and Nef-25, which were produced in E. coli. Nef-25 lacked the first 18 N-terminal residues of Nef-27 and both were nonmyristylated. Nef-27 fuses small unilamellar dipalmitoyl phosphatidylcholine vesicles (SUVs), as indicated by enhanced light scattering of SUVs and lipid mixing using concentration-dependent fluorescence dequenching. Nef-27 also causes the appearance of a shifted isotropic peak in the 31P NMR spectra of these vesicles, suggesting that protein interactions induce nonlamellar lipid structures. Recombinant Nef-25, which lacks only the 18 N-terminal residues of Nef-27, does not fuse vesicles and has little effect on the 31P NMR spectra. On the other hand, synthetic peptides consisting of 18 or 21 of the N-terminal residues of Nef-27 are strongly membrane perturbing, causing vesicle fusion and inducing isotropic peaks in the 31P NMR spectrum. Endogenous fluorescence spectra of the N-terminal peptide (21 residues) with SUVs show that the N-terminal sequence of Nef may achieve these perturbing effects by inserting its hydrophobic side into the lipid bilayer. Theoretical calculations using hydrophobic moment plot analysis indicate that short-length stretches (i.e., six amino acid residues) of the N-terminal sequence may insert into the lipid bilayer as multimeric alpha helices or beta sheets. The above-described membrane activities of Nef-27, which principally reside in its N-terminal domain, may play critical role(s) in certain functional properties of the full-length protein. For example, the fusogenic activity of the N-terminal sequence may be involved in the extracellular release of Nef-27, much of which appears to be associated with small membrane vesicles. The fusion activity may also be relevant to the ability of Nef-27 to downregulate CD4 and IL-2 receptors when this protein is electroporated into cultured lymphocytes, an activity not possessed by Nef-25.
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MESH Headings
- 1,2-Dipalmitoylphosphatidylcholine
- Amino Acid Sequence
- Antigens, Bacterial/chemistry
- Gene Products, nef/biosynthesis
- Gene Products, nef/chemistry
- Gene Products, nef/metabolism
- HIV-1/metabolism
- Light
- Liposomes
- Magnetic Resonance Spectroscopy
- Membrane Fusion
- Molecular Sequence Data
- Peptide Fragments/chemical synthesis
- Peptide Fragments/chemistry
- Protein Structure, Secondary
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/metabolism
- Scattering, Radiation
- Sequence Homology, Amino Acid
- Spectrometry, Fluorescence
- nef Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- C C Curtain
- Biomolecular Research Institute, Parkville, Victoria, Australia
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31
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Gordon LM, Curtain CC, McCloyn V, Kirkpatrick A, Mobley PW, Waring AJ. The amino-terminal peptide of HIV-1 gp41 interacts with human serum albumin. AIDS Res Hum Retroviruses 1993; 9:1145-56. [PMID: 8312056 DOI: 10.1089/aid.1993.9.1145] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Structural and functional studies were made to assess interactions between human serum albumin (HSA) and the amino-terminal peptide (FP-I; 23-residue peptide 519-541) of glycoprotein 41,000 (gp41) of human immunodeficiency virus type-1 (HIV-1). Circular dichroism (CD) spectroscopy indicated that the peptide binds to albumin with dominant alpha-helical character. Peptide binding to albumin was also examined using FP-I spin labeled at either the amino-terminal alanine (FP-II; residue 519) or methionine (FP-III; position 537). Electron spin resonance (ESR) spectra of FP-II bound to HSA at 38 degrees C indicated that the spin label at the amino-terminal residue (Ala-519) was motionally restricted. The ESR spectrum of 12-nitroxide stearate (12-NS)-labeled HSA was identical to that obtained with FP-II, indicating that the reporter groups for the 12-NS and FP-II probes are similarly bound to albumin. Contrarily, ESR spectra of HSA labeled with FP-III indicated high mobility for the reporter group (Met-537) at the aqueous-protein interface. This suggests that the N-terminal gp41 peptide binds as an alpha helix (residues 519-536) to fatty acid sites on HSA, such that Ala-519 of the peptide residues in the interior of the protein while Met-537 lies outside the protein in aqueous solution. It is also of interest that addition of HSA to human red blood cells dramatically reduced the ability of FP-I to induce hemolysis, presumably through peptide-albumin binding that inhibited FP-I interactions with red cell membranes. The significance of these results focuses on the following three points. The first is that high serum levels of albumin may limit the efficacy of anti-HIV therapies using peptides based on the N-terminal gp41 domain. The second is that the elucidation of FP-I and HSA interactions with physical techniques may provide clues on the molecular features underlying viral FP-I combination with receptors on the target cell surface. Last, the affinity of albumin for the N-terminal gp41 peptide may play a subordinate role in the blocking of HIV infectivity in vitro that has been reported for chemically modified albumins.
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Affiliation(s)
- L M Gordon
- Department of Pediatrics, Drew University, King Medical Center/UCLA 90059
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32
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Haynes BF, Arthur LO, Frost P, Matthews TJ, Langlois AJ, Palker TJ, Hart MK, Scearce RM, Jones DM, McDanal C. Conversion of an immunogenic human immunodeficiency virus (HIV) envelope synthetic peptide to a tolerogen in chimpanzees by the fusogenic domain of HIV gp41 envelope protein. J Exp Med 1993; 177:717-27. [PMID: 7679708 PMCID: PMC2190925 DOI: 10.1084/jem.177.3.717] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The fusogenic (F) domain of human immunodeficiency virus (HIV) gp41 envelope (env) protein has sequence similarities to many virus and mediates the fusion of HIV-infected cells. During a survey of the immunogenicity of HIV env peptides in chimpanzees, we have observed that HIV peptide immunogenicity was dramatically altered by the NH2-terminal synthesis of the gp41 F domain to an otherwise immunogenic peptide. We compared two hybrid peptide types comprised of T helper (Th) and B cell epitopes of HIV gp120 env protein for their immunogenicity in chimpanzees. The Th-B epitope hybrid peptides contained the HIV gp120 Th cell determinant, T1 (amino acids [aa] 428-440)-synthesized NH2 terminal to gp120 V3 loop peptides, which contain B cell epitopes that induce anti-HIV-neutralizing antibodies (SP10IIIB [aa 303-321] and SP10IIIB [A] [aa 303-327]). The F-Th-B peptide contained the HIV gp41 F domain of HIVIIIB gp41 (aa 519-530)-synthesized NH2 terminal to the Th-B peptide. Whereas Th-B peptides were potent immunogens for chimpanzee antibody and T cell-proliferative responses, the F-Th-B peptide induced lower anti-HIV gp120 T and B cell responses. Moreover, immunization of chimpanzees with F-Th-B peptide but not Th-B peptides induced a significant decrease in peripheral blood T lymphocytes (mean decrease during immunization, 52%; p < 0.02). Chimpanzees previously immunized with F-Th-B peptide did not respond well to immunization with Th-B peptide with T or B cell responses to HIV peptides, demonstrating that the F-Th-B peptide induced immune hyporesponsiveness to Th and B HIV gp120 env determinants. These observations raise the hypothesis that the HIV gp41 env F domain may be a biologically active immunoregulatory peptide in vivo, and by an as yet uncharacterized mechanism, promotes primate immune system hyporesponsiveness to otherwise immunogenic peptides.
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Affiliation(s)
- B F Haynes
- Department of Medicine, Duke Center for AIDS Research, Duke University Medical Center, Durham, North Carolina 27710
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33
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Gordon LM, Curtain CC, Zhong YC, Kirkpatrick A, Mobley PW, Waring AJ. The amino-terminal peptide of HIV-1 glycoprotein 41 interacts with human erythrocyte membranes: peptide conformation, orientation and aggregation. Biochim Biophys Acta Mol Basis Dis 1992; 1139:257-74. [PMID: 1355364 DOI: 10.1016/0925-4439(92)90099-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Structural studies assessed interactions between the amino-terminal peptide (FP-I; 23 residues 519-541) of the glycoprotein 41,000 (gp41) of Human Immunodeficiency Virus Type-1 (HIV-1) and human erythrocyte membranes and simulated membrane environments. Peptide binding was examined at sub-hemolytic (approx. less than 5 microM) and hemolytic (greater than or equal to 5 microM) doses (Mobley et al. (1992) Biochem. Biophys. Acta 1139, 251-256), using circular dichroism (CD) and Fourier-transform infrared (FTIR) measurements with FP-I, and electron spin resonance (ESR) studies employing FP-I spin-labeled at either the amino-terminal alanine (FP-II; residue 519) or methionine (FP-III; position 537). In the sub-lytic regime, FP-I binds to both erythrocyte lipids and dispersions of SDS with high alpha-helicity. Further, ESR spectra of FP-II labeled erythrocyte ghosts indicated peptide binding to both lipid and protein. In ghost lipids, FP-II was monomeric and exhibited low polarity and rapid, anisotropic motion about its long molecular axis (i.e., alpha-helical axis), with restricted motion away from this axis. The spin-label at the amino-terminal residue (Ala-519) is insensitive to the aqueous broadening agent chromium oxalate and buried within the hydrophobic core of the membrane; the angle that the alpha-helix (residues 519-536) makes to the normal of the bilayer plane is either 0 degree or 40 degrees. Contrarily, ESR spectra of ghost lipids labeled with sub-lytic doses of FP-III indicated high mobility and polarity for the reporter group (Met-537) at the aqueous-membrane interface, as well as extreme sensitivity to chromium oxalate. At lytic FP-I doses, CD and FTIR showed both alpha-helix and beta-structure for peptide in ghost lipids or detergent, while ESR spectra of high-loaded FP-II in ghost membranes indicated peptide aggregates. Membrane aggregates of FP-I may be involved in hemolysis, and models are suggested for N-terminal gp41 peptide participation in HIV-induced fusion and cytolysis.
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Affiliation(s)
- L M Gordon
- Department of Pediatrics, King-Drew Medical Center/UCLA 90059
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