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Miłogrodzka I, Le Brun AP, Banaszak Holl MM, van 't Hag L. HIV and influenza fusion peptide interactions with (dis)ordered lipid bilayers: Understanding mechanisms and implications for antimicrobial and antiviral approaches. J Colloid Interface Sci 2024; 670:563-575. [PMID: 38776691 DOI: 10.1016/j.jcis.2024.05.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/05/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
The interactions of viral fusion peptides from influenza (E4K and Ac-E4K) and human immunodeficiency virus (gp41 and Ac-gp41) with planar lipid bilayers and monolayers was investigated herein. A combination of surface-sensitive techniques, including quartz crystal microbalance with dissipation (QCM-D), Langmuir-Blodgett area-pressure isotherms with Micro-Brewster angle microscopy, and neutron reflectometry, was employed. Differences in the interactions of the viral fusion peptides with lipid bilayers featuring ordered and disordered phases, as well as lipid rafts, were revealed. The HIV fusion peptide (gp41) exhibited strong binding to the DOPC/DOPS bilayer, comprising a liquid disordered phase, with neutron reflectometry (NR) showing interaction with the bilayer's headgroup area. Conversely, negligible binding was observed with lipid bilayers in a liquid ordered phase. Notably, the influenza peptide (E4K) demonstrated slower binding kinetics with DOPC/DOPS bilayers and distinct interactions compared to gp41, as observed through QCM-D. This suggests different mechanisms of interaction with the lipid bilayers: one peptide interacts more within the headgroup region, while the other is more involved in transmembrane interactions. These findings hold implications for understanding viral fusion mechanisms and developing antimicrobials and antivirals targeting membrane interactions. The differential binding behaviours of the viral fusion peptides underscore the importance of considering membrane composition and properties in therapeutic strategy design.
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Affiliation(s)
- Izabela Miłogrodzka
- Department of Chemical and Biological Engineering, Monash University, Clayton, Victoria, Australia; Australian Synchrotron, Clayton, Victoria, Australia
| | - Anton P Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW, Australia
| | - Mark M Banaszak Holl
- Department of Chemical and Biological Engineering, Monash University, Clayton, Victoria, Australia; Department of Mechanical and Materials Engineering, University of Alabama at Birmingham, Birmingham, AL, USA; Division of Pulmonology, Allergy, and Critical Care Medicine, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Leonie van 't Hag
- Department of Chemical and Biological Engineering, Monash University, Clayton, Victoria, Australia.
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2
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Shekunov EV, Efimova SS, Kever LV, Ishmanov TF, Ostroumova OS. Lipid Selectivity of Membrane Action of the Fragments of Fusion Peptides of Marburg and Ebola Viruses. Int J Mol Sci 2024; 25:9901. [PMID: 39337389 PMCID: PMC11432738 DOI: 10.3390/ijms25189901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Revised: 08/26/2024] [Accepted: 09/10/2024] [Indexed: 09/30/2024] Open
Abstract
The life cycle of Ebola and Marburg viruses includes a step of the virion envelope fusion with the cell membrane. Here, we analyzed whether the fusion of liposome membranes under the action of fragments of fusion peptides of Ebola and Marburg viruses depends on the composition of lipid vesicles. A fluorescence assay and electron microscopy were used to quantify the fusogenic activity of the virus fusion peptides and to identify the lipid determinants affecting membrane merging. Differential scanning calorimetry of lipid phase transitions revealed alterations in the physical properties of the lipid matrix produced by virus fusion peptides. Additionally, we found that plant polyphenols, quercetin, and myricetin inhibited vesicle fusion induced by the Marburg virus fusion peptide.
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Affiliation(s)
- Egor V Shekunov
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
| | - Svetlana S Efimova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
| | - Lyudmila V Kever
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
| | - Tagir F Ishmanov
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
| | - Olga S Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
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3
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Rice A, Zimmerberg J, Pastor RW. Initiation and evolution of pores formed by influenza fusion peptides probed by lysolipid inclusion. Biophys J 2023; 122:1018-1032. [PMID: 36575795 PMCID: PMC10111278 DOI: 10.1016/j.bpj.2022.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/09/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
The fusion peptide (FP) domain is necessary for the fusogenic activity of spike proteins in a variety of enveloped viruses, allowing the virus to infect the host cell, and is the only part of the protein that interacts directly with the target membrane lipid tails during fusion. There are consistent findings of poration by this domain in experimental model membrane systems, and, in certain conditions, the isolated FPs can generate pores. Here, we use molecular dynamics simulations to investigate the specifics of how these FP-induced pores form in membranes with different compositions of lysolipid and POPC. The simulations show that pores form spontaneously at high lysolipid concentrations via hybrid intermediates, where FP aggregates in the cis leaflet tilt to form a funnel-like structure that spans the leaflet and locally reduces the hydrophobic thickness that must be traversed by water to form a pore. By restraining a single FP within an FP aggregate to this tilted conformation, pores can be formed in lower-lysolipid-content membranes, including pure POPC, on the 100-ns timescale, much more rapidly than in unbiased simulations in bilayers with the same composition. The pore formation pathway is similar to the spontaneous formation in high lysolipid concentrations. Depending on the membrane composition, the pores can be metastable (as seen in POPC) or lead to membrane rupture.
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Affiliation(s)
- Amy Rice
- Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Joshua Zimmerberg
- Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland.
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4
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Rice A, Haldar S, Wang E, Blank PS, Akimov SA, Galimzyanov TR, Pastor RW, Zimmerberg J. Planar aggregation of the influenza viral fusion peptide alters membrane structure and hydration, promoting poration. Nat Commun 2022; 13:7336. [PMID: 36470871 PMCID: PMC9722698 DOI: 10.1038/s41467-022-34576-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/28/2022] [Indexed: 12/07/2022] Open
Abstract
To infect, enveloped viruses employ spike protein, spearheaded by its amphipathic fusion peptide (FP), that upon activation extends out from the viral surface to embed into the target cellular membrane. Here we report that synthesized influenza virus FPs are membrane active, generating pores in giant unilamellar vesicles (GUV), and thus potentially explain both influenza virus' hemolytic activity and the liposome poration seen in cryo-electron tomography. Experimentally, FPs are heterogeneously distributed on the GUV at the time of poration. Consistent with this heterogeneous distribution, molecular dynamics (MD) simulations of asymmetric bilayers with different numbers of FPs in one leaflet show FP aggregation. At the center of FP aggregates, a profound change in the membrane structure results in thinning, higher water permeability, and curvature. Ultimately, a hybrid bilayer nanodomain forms with one lipidic leaflet and one peptidic leaflet. Membrane elastic theory predicts a reduced barrier to water pore formation when even a dimer of FPs thins the membrane as above, and the FPs of that dimer tilt, to continue the leaflet bending initiated by the hydrophobic mismatch between the FP dimer and the surrounding lipid.
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Affiliation(s)
- Amy Rice
- grid.94365.3d0000 0001 2297 5165Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Sourav Haldar
- grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA ,grid.418363.b0000 0004 0506 6543Present Address: Division of Virus Research and Therapeutics, CSIR-Central Drug Research Institute, Lucknow, UP India
| | - Eric Wang
- grid.94365.3d0000 0001 2297 5165Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD USA ,grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Paul S. Blank
- grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
| | - Sergey A. Akimov
- grid.4886.20000 0001 2192 9124A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
| | - Timur R. Galimzyanov
- grid.4886.20000 0001 2192 9124A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia ,grid.35043.310000 0001 0010 3972National University of Science and Technology “MISiS”, 4 Leninskiy Prospect, Moscow, Russia
| | - Richard W. Pastor
- grid.94365.3d0000 0001 2297 5165Laboratory of Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD USA
| | - Joshua Zimmerberg
- grid.94365.3d0000 0001 2297 5165Section on Integrative Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD USA
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5
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Effects of Cholesterol on Lipid Vesicle Fusion Mediated by Infectious Salmon Anaemia Virus Fusion Peptides. Colloids Surf B Biointerfaces 2022; 217:112684. [DOI: 10.1016/j.colsurfb.2022.112684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 11/19/2022]
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6
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Joardar A, Pattnaik GP, Chakraborty H. Combination of Oleic Acid and the gp41 Fusion Peptide Switches the Phosphatidylethanolamine-Induced Membrane Fusion Mechanism from a Nonclassical to a Classical Stalk Model. J Phys Chem B 2022; 126:3673-3684. [PMID: 35580344 DOI: 10.1021/acs.jpcb.2c00307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Membrane fusion is considered to be one of the crucial processes for the existence of eukaryotes and the entry of enveloped viruses into host cells. The fusion mechanism depends on the lipid composition of the membrane as well as the properties of fusion proteins or peptides. The gp41 fusion peptide from the human immunodeficiency virus (HIV) is known to catalyze membrane fusion by altering the physical properties of the membrane. Earlier, we demonstrated that a membrane containing 30 mol % phosphatidylethanolamine (PE) circumvents the classical stalk model because of its intrinsic negative curvature. In this work, we demonstrated how the gp41 fusion peptide influences the fusion mechanism of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dioleoyl-sn-glycero-3-phos-pho¬ethanolamine (DOPE) (70/30 mol %) membranes. We further evaluated the effect of the same peptide on the mechanism of fusion for membranes containing 30 mol % PE and a fatty acid with an intrinsic positive curvature (oleic acid (OA)). Our results show that gp41 switches the fusion mechanism from a nonclassical to a classical stalk model when membranes contain OA, but fails to do so for DOPC/DOPE membranes. This could be due to the extreme influence of the intrinsic negative curvature of PE, which is partially downregulated in the presence of OA.
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Affiliation(s)
- Ankita Joardar
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha 768 019, India
| | | | - Hirak Chakraborty
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha 768 019, India
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7
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Tuerkova A, Kasson PM. Computational methods to study enveloped viral entry. Biochem Soc Trans 2021; 49:2527-2537. [PMID: 34783344 PMCID: PMC10184508 DOI: 10.1042/bst20210190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/25/2021] [Accepted: 10/27/2021] [Indexed: 12/15/2022]
Abstract
The protein-membrane interactions that mediate viral infection occur via loosely ordered, transient assemblies, creating challenges for high-resolution structure determination. Computational methods and in particular molecular dynamics simulation have thus become important adjuncts for integrating experimental data, developing mechanistic models, and suggesting testable hypotheses regarding viral function. However, the large molecular scales of virus-host interaction also create challenges for detailed molecular simulation. For this reason, continuum membrane models have played a large historical role, although they have become less favored for high-resolution models of protein assemblies and lipid organization. Here, we review recent progress in the field, with an emphasis on the insight that has been gained using a mixture of coarse-grained and atomic-resolution molecular dynamics simulations. Based on successes and challenges to date, we suggest a multiresolution strategy that should yield the best mixture of computational efficiency and physical fidelity. This strategy may facilitate further simulations of viral entry by a broader range of viruses, helping illuminate the diversity of viral entry strategies and the essential common elements that can be targeted for antiviral therapies.
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Affiliation(s)
- Alzbeta Tuerkova
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden
| | - Peter M Kasson
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala 75124, Sweden
- Departments of Molecular Physiology and Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, U.S.A
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8
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Moreira P, Sequeira AM, Pereira S, Rodrigues R, Rocha M, Lousa D. ViralFP: A Web Application of Viral Fusion Proteins. FRONTIERS IN MEDICAL TECHNOLOGY 2021; 3:722392. [PMID: 35047951 PMCID: PMC8757699 DOI: 10.3389/fmedt.2021.722392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 07/19/2021] [Indexed: 12/03/2022] Open
Abstract
Viral fusion proteins are attached to the membrane of enveloped viruses (a group that includes Coronaviruses, Dengue, HIV and Influenza) and catalyze fusion between the viral and host membranes, enabling the virus to insert its genetic material into the host cell. Given the importance of these biomolecules, this work presents a centralized database containing the most relevant information on viral fusion proteins, available through a free-to-use web server accessible through the URL https://viralfp.bio.di.uminho.pt/. This web application contains several bioinformatic tools, such as Clustal sequence alignment and Weblogo, including as well a machine learning-based tool capable of predicting the location of fusion peptides (the component of fusion proteins that inserts into the host's cell membrane) within the fusion protein sequence. Given the crucial role of these proteins in viral infection, their importance as natural targets of our immune system and their potential as therapeutic targets, this web application aims to foster our ability to fight pathogenic viruses.
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Affiliation(s)
- Pedro Moreira
- Centro de Engenharia Biológica, Escola de Engenharia da Universidade do Minho, Braga, Portugal
| | - Ana Marta Sequeira
- Centro de Engenharia Biológica, Escola de Engenharia da Universidade do Minho, Braga, Portugal
| | - Sara Pereira
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Rúben Rodrigues
- Centro de Engenharia Biológica, Escola de Engenharia da Universidade do Minho, Braga, Portugal
| | - Miguel Rocha
- Centro de Engenharia Biológica, Escola de Engenharia da Universidade do Minho, Braga, Portugal
| | - Diana Lousa
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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9
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The role of fusion peptides in depth-dependent membrane organization and dynamics in promoting membrane fusion. Chem Phys Lipids 2020; 234:105025. [PMID: 33301753 DOI: 10.1016/j.chemphyslip.2020.105025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/16/2020] [Accepted: 12/03/2020] [Indexed: 11/24/2022]
Abstract
Membrane fusion is an important event in the life of eukaryotes; occurs in several processes such as endocytosis, exocytosis, cellular trafficking, compartmentalization, import of nutrients and export of waste, vesiculation, inter cellular communication, and fertilization. The enveloped viruses as well utilize fusion between the viral envelope and host cell membrane for infection. The stretch of 20-25 amino acids located at the N-terminus of the fusion protein, known as fusion peptide, plays a decisive role in the fusion process. The stalk model of membrane fusion postulated a common route of bilayer transformation for stalk, transmembrane contact, and pore formation; and fusion peptide is believed to facilitate bilayer transformation to promote membrane fusion. The peptide-induced change in depth-dependent organization and dynamics could provide important information in understanding the role of fusion peptide in membrane fusion. In this review, we have discussed about three depth-dependent properties of the membrane such as rigidity, polarity and heterogeneity, and the impact of fusion peptide on these three membrane properties.
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Kumar S, Kaur N, Mithu VS. Amphiphilic ionic liquid induced fusion of phospholipid liposomes. Phys Chem Chem Phys 2020; 22:25255-25263. [DOI: 10.1039/d0cp04014b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The impact of increasing concentration of imidazolium-based ionic liquids ([CnMIM]+[Br]−) on the structural integrity of large unilamellar vesicles (LUVs) made of pure phosphatidylcholine (PC) and phosphatidylglycerol (PG) lipids.
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Affiliation(s)
- Sandeep Kumar
- Department of Chemistry
- Guru Nanak Dev University
- Amritsar-143005
- India
| | - Navleen Kaur
- Department of Chemistry
- Guru Nanak Dev University
- Amritsar-143005
- India
| | - Venus Singh Mithu
- Department of Chemistry
- Guru Nanak Dev University
- Amritsar-143005
- India
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11
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Meher G, Sinha S, Pattnaik GP, Ghosh Dastidar S, Chakraborty H. Cholesterol Modulates Membrane Properties and the Interaction of gp41 Fusion Peptide To Promote Membrane Fusion. J Phys Chem B 2019; 123:7113-7122. [PMID: 31345037 DOI: 10.1021/acs.jpcb.9b04577] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An envelope glycoprotein, gp41, is crucial for the entry of human immunodeficiency virus (HIV) into the host cell. The 20-23 N-terminal amino acid sequence of gp41 plays an important role in promoting fusion between viral and host cells. Interestingly, the structure and function of the fusion peptide are extremely sensitive to the characteristics of the lipid environment. In this present work, we have extensively utilized steady-state and time-resolved fluorescence spectroscopy in tandem with molecular dynamics simulation to elucidate peptide binding and peptide-induced perturbation to the membrane. We have used two depth-dependent fluorescence probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and its trimethylammonium derivative (TMA-DPH), to monitor the effect of peptide binding along the bilayer normal and have reconciled the experimental observation with the insights from the simulated molecular events. We have further monitored the effect of membrane cholesterol on peptide-induced membrane perturbation. The molecular dynamics simulation data show that the peptide alters the membrane properties in the vicinity of the peptide and it penetrates to a larger extent into the bilayer when the membrane contains cholesterol. Our results clearly elucidate that cholesterol alters the membrane physical properties in favor of membrane fusion and interaction pattern of the fusion peptide with the membrane in a concentration-dependent fashion. The role of cholesterol is specifically important as the host eukaryotic cells contain a decent amount of cholesterol that might be critical for the entry of HIV into the host cells.
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Affiliation(s)
- Geetanjali Meher
- School of Chemistry , Sambalpur University , Jyoti Vihar, Burla , Odisha 768 019 , India
| | - Souvik Sinha
- Division of Bioinformatics , Bose Institute , P-1/12 C.I.T. Scheme VII M , Kolkata 700054 , India
| | - Gourab Prasad Pattnaik
- School of Chemistry , Sambalpur University , Jyoti Vihar, Burla , Odisha 768 019 , India
| | - Shubhra Ghosh Dastidar
- Division of Bioinformatics , Bose Institute , P-1/12 C.I.T. Scheme VII M , Kolkata 700054 , India
| | - Hirak Chakraborty
- School of Chemistry , Sambalpur University , Jyoti Vihar, Burla , Odisha 768 019 , India
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12
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Meher G, Chakraborty H. Membrane Composition Modulates Fusion by Altering Membrane Properties and Fusion Peptide Structure. J Membr Biol 2019; 252:261-272. [PMID: 31011762 PMCID: PMC7079885 DOI: 10.1007/s00232-019-00064-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 04/12/2019] [Indexed: 01/21/2023]
Abstract
Membrane fusion, one of the most essential processes in the life of eukaryotes, occurs when two separate lipid bilayers merge into a continuous bilayer and internal contents of two separated membranes mingle. There is a certain class of proteins that assist the binding of the viral envelope to the target host cell and catalyzing fusion. All class I viral fusion proteins contain a highly conserved 20–25 amino-acid amphipathic peptide at the N-terminus, which is essential for fusion activity and is termed as the ‘fusion peptide’. It has been shown that insertion of fusion peptides into the host membrane and the perturbation in the membrane generated thereby is crucial for membrane fusion. Significant efforts have been given in the last couple of decades to understand the lipid-dependence of structure and function of the fusion peptide in membranes to understand the role of lipid compositions in membrane fusion. In addition, the lipid compositions further change the membrane physical properties and alter the mechanism and extent of membrane fusion. Therefore, lipid compositions modulate membrane fusion by changing membrane physical properties and altering structure of the fusion peptide.
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Affiliation(s)
- Geetanjali Meher
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768 019, India
| | - Hirak Chakraborty
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha, 768 019, India.
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13
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Pattnaik GP, Chakraborty H. Coronin 1 derived tryptophan-aspartic acid containing peptides inhibit membrane fusion. Chem Phys Lipids 2018; 217:35-42. [DOI: 10.1016/j.chemphyslip.2018.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/26/2018] [Accepted: 10/26/2018] [Indexed: 11/16/2022]
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14
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Abdoli A, Alirezaei M, Mehrbod P, Forouzanfar F. Autophagy: The multi-purpose bridge in viral infections and host cells. Rev Med Virol 2018; 28:e1973. [PMID: 29709097 PMCID: PMC7169200 DOI: 10.1002/rmv.1973] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 02/03/2018] [Accepted: 02/09/2018] [Indexed: 02/06/2023]
Abstract
Autophagy signaling pathway is involved in cellular homeostasis, developmental processes, cellular stress responses, and immune pathways. The aim of this review is to summarize the relationship between autophagy and viruses. It is not possible to be fully comprehensive, or to provide a complete "overview of all viruses". In this review, we will focus on the interaction of autophagy and viruses and survey how human viruses exploit multiple steps in the autophagy pathway to help viral propagation and escape immune response. We discuss the role that macroautophagy plays in cells infected with hepatitis C virus, hepatitis B virus, rotavirus gastroenteritis, immune cells infected with human immunodeficiency virus, and viral respiratory tract infections both influenza virus and coronavirus.
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Affiliation(s)
- Asghar Abdoli
- Department of Hepatitis and AIDSPasteur Institute of IranTehranIran
| | - Mehrdad Alirezaei
- Department of Immunology and Microbial ScienceThe Scripps Research InstituteLa JollaCaliforniaUSA
| | - Parvaneh Mehrbod
- Influenza and Other Respiratory Viruses Dept.Pasteur Institute of IranTehranIran
| | - Faezeh Forouzanfar
- University of Strasbourg, EA7292, DHPIInstitute of Parasitology and Tropical Pathology StrasbourgFrance
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15
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Pattnaik GP, Meher G, Chakraborty H. Exploring the Mechanism of Viral Peptide-Induced Membrane Fusion. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1112:69-78. [PMID: 30637691 DOI: 10.1007/978-981-13-3065-0_6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Membrane fusion is essential in several cellular processes in the existence of eukaryotic cells such as cellular trafficking, compartmentalization, intercellular communication, sexual reproduction, cell division, and endo- and exocytosis. Membrane fusion proceeds in model membranes as well as biological membranes through the rearrangement of lipids. The stalk hypothesis provides a picture of the general nature of lipid rearrangement based on mechanical properties and phase behavior of water-lipid mesomorphic systems. In spite of extensive research on exploring the mechanism of membrane fusion, a clear molecular understanding of intermediate and pore formation is lacking. In addition, the mechanism by which proteins and peptides reduce the activation energy for stalk and pore formation is not yet clear though there are several propositions on how they catalyze membrane fusion. In this review, we have discussed about various putative functions of fusion peptides by which they reduce activation barrier and thus promote membrane fusion. A careful analysis of the discussed effects of fusion peptides on membranes might open up new possibilities for better understanding of the membrane fusion mechanism.
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16
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Membrane remodeling by the M2 amphipathic helix drives influenza virus membrane scission. Sci Rep 2017; 7:44695. [PMID: 28317901 PMCID: PMC5357790 DOI: 10.1038/srep44695] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 02/13/2017] [Indexed: 02/07/2023] Open
Abstract
Membrane scission is a crucial step in all budding processes, from endocytosis to viral budding. Many proteins have been associated with scission, though the underlying molecular details of how scission is accomplished often remain unknown. Here, we investigate the process of M2-mediated membrane scission during the budding of influenza viruses. Residues 50–61 of the viral M2 protein bind membrane and form an amphipathic α-helix (AH). Membrane binding requires hydrophobic interactions with the lipid tails but not charged interactions with the lipid headgroups. Upon binding, the M2AH induces membrane curvature and lipid ordering, constricting and destabilizing the membrane neck, causing scission. We further show that AHs in the cellular proteins Arf1 and Epsin1 behave in a similar manner. Together, they represent a class of membrane-induced AH domains that alter membrane curvature and fluidity, mediating the scission of constricted membrane necks in multiple biological pathways.
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Changes in lipid bilayer structure caused by the helix-to-sheet transition of an HIV-1 gp41 fusion peptide derivative. Chem Phys Lipids 2017; 203:46-53. [DOI: 10.1016/j.chemphyslip.2017.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 11/20/2022]
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18
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Chakraborty H, Lentz BR, Kombrabail M, Krishnamoorthy G, Chattopadhyay A. Depth-Dependent Membrane Ordering by Hemagglutinin Fusion Peptide Promotes Fusion. J Phys Chem B 2017; 121:1640-1648. [DOI: 10.1021/acs.jpcb.7b00684] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hirak Chakraborty
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
- School
of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Odisha 768 019, India
| | - Barry R. Lentz
- Department
of Biochemistry and Biophysics and Program in Molecular and Cellular
Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Mamata Kombrabail
- Department
of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhaba Road, Mumbai, India
| | - G. Krishnamoorthy
- Department
of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhaba Road, Mumbai, India
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19
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Klug YA, Rotem E, Schwarzer R, Shai Y. Mapping out the intricate relationship of the HIV envelope protein and the membrane environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:550-560. [PMID: 27793589 DOI: 10.1016/j.bbamem.2016.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023]
Abstract
The HIV gp160 envelope fusion protein is situated in the viral membrane and mediates virus entry into its host cell. Increasing evidence suggests that virtually all parts of the HIV envelope are structurally and functionally dependent on membranes. Protein-lipid interactions and membrane properties influence the dynamics of a manifold of gp160 biological activities such as membrane fusion, immune suppression and gp160 incorporation into virions during HIV budding and assembly. In the following we will summarize our current understanding of this interdependence between membrane interaction, structural conformation and functionality of the different gp160 domains. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider.
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Affiliation(s)
- Yoel A Klug
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Etai Rotem
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Roland Schwarzer
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yechiel Shai
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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20
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Pratumyot Y, Torres OB, Bong D. Assessment of RNA carrier function in peptide amphiphiles derived from the HIV fusion peptide. Peptides 2016; 79:27-30. [PMID: 26988874 PMCID: PMC4842095 DOI: 10.1016/j.peptides.2016.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/08/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
Abstract
A small library of amphiphilic peptides has been evaluated for duplex RNA carrier function into A549 cells. We studied peptides in which a C-terminal 7-residue cationic domain is attached to a neutral/hydrophobic 23-residue domain that is based on the viral fusion peptide of HIV. We also examined peptides in which the cationic charge was evenly distributed throughout the peptide. Strikingly, subtle sequence variations in the hydrophobic domain that do not alter net hydrophobicity result in wide variation in RNA uptake. Additionally, cyclic cystine variants are much less active as RNA carriers than their open-chain cysteine analogs. With regard to electrostatic effects, we find that lysine is less effective than arginine in facilitating uptake, and that even distribution of cationic residues throughout the peptide sequence results in especially effective RNA carrier function. Overall, minor changes in peptide hydrophobicity, flexibility and charge distribution can significantly alter carrier function. We hypothesize this is due to altered properties of the peptide-RNA assembly rather than peptide secondary structure.
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Affiliation(s)
- Yaowalak Pratumyot
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, OH 43210, United States
| | - Oscar B Torres
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, OH 43210, United States
| | - Dennis Bong
- Department of Chemistry and Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, OH 43210, United States.
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21
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White JM, Whittaker GR. Fusion of Enveloped Viruses in Endosomes. Traffic 2016; 17:593-614. [PMID: 26935856 PMCID: PMC4866878 DOI: 10.1111/tra.12389] [Citation(s) in RCA: 282] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 12/12/2022]
Abstract
Ari Helenius launched the field of enveloped virus fusion in endosomes with a seminal paper in the Journal of Cell Biology in 1980. In the intervening years, a great deal has been learned about the structures and mechanisms of viral membrane fusion proteins as well as about the endosomes in which different enveloped viruses fuse and the endosomal cues that trigger fusion. We now recognize three classes of viral membrane fusion proteins based on structural criteria and four mechanisms of fusion triggering. After reviewing general features of viral membrane fusion proteins and viral fusion in endosomes, we delve into three characterized mechanisms for viral fusion triggering in endosomes: by low pH, by receptor binding plus low pH and by receptor binding plus the action of a protease. We end with a discussion of viruses that may employ novel endosomal fusion‐triggering mechanisms. A key take‐home message is that enveloped viruses that enter cells by fusing in endosomes traverse the endocytic pathway until they reach an endosome that has all of the environmental conditions (pH, proteases, ions, intracellular receptors and lipid composition) to (if needed) prime and (in all cases) trigger the fusion protein and to support membrane fusion.
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Affiliation(s)
- Judith M White
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Gary R Whittaker
- Department of Microbiology & Immunology, Cornell University, Ithaca, NY, USA
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22
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Victor BL, Lousa D, Antunes JM, Soares CM. Self-assembly molecular dynamics simulations shed light into the interaction of the influenza fusion Peptide with a membrane bilayer. J Chem Inf Model 2015; 55:795-805. [PMID: 25826469 DOI: 10.1021/ci500756v] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Influenza virus is one of the most devastating human pathogens. In order to infect host cells, this virus fuses its membrane with the host membrane in a process mediated by the glycoprotein hemagglutinin. During fusion, the N-terminal region of hemagglutinin, which is known as the fusion peptide (FP), inserts into the host membrane, promoting lipid mixing between the viral and host membranes. Therefore, this peptide plays a key role in the fusion process, but the exact mechanism by which it promotes lipid mixing is still unclear. To shed light into this matter, we performed molecular dynamics (MD) simulations of the influenza FP in different environments (water, dodecylphosphocholine (DPC) micelles, and a dimyristoylphosphatidylcholine (DMPC) membrane). While in pure water the peptide lost its initial secondary structure, in simulations performed in the presence of DPC micelles it remained stable, in agreement with previous experimental observations. In simulations performed in the presence of a preassembled DMPC bilayer, the peptide became unstructured and was unable to insert into the membrane as a result of technical limitations of the method used. To overcome this problem, we used a self-assembly strategy, assembling the membrane together with the peptide. These simulations revealed that the peptide can adopt a membrane-spanning conformation, which had not been predicted by previous MD simulation studies. The peptide insertion had a strong effect on the membrane, lowering the bilayer thickness, disordering nearby lipids, and promoting lipid tail protrusion. These results contribute to a better understanding of the role of the FP in the fusion process.
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Affiliation(s)
- Bruno L Victor
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Diana Lousa
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Jorge M Antunes
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Cláudio M Soares
- ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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23
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Jia L, Liang S, Sackett K, Xie L, Ghosh U, Weliky DP. REDOR solid-state NMR as a probe of the membrane locations of membrane-associated peptides and proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 253:154-65. [PMID: 25797012 PMCID: PMC4371142 DOI: 10.1016/j.jmr.2014.12.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/21/2014] [Accepted: 12/24/2014] [Indexed: 06/01/2023]
Abstract
Rotational-echo double-resonance (REDOR) solid-state NMR is applied to probe the membrane locations of specific residues of membrane proteins. Couplings are measured between protein (13)CO nuclei and membrane lipid or cholesterol (2)H and (31)P nuclei. Specific (13)CO labeling is used to enable unambiguous assignment and (2)H labeling covers a small region of the lipid or cholesterol molecule. The (13)CO-(31)P and (13)CO-(2)H REDOR respectively probe proximity to the membrane headgroup region and proximity to specific insertion depths within the membrane hydrocarbon core. One strength of the REDOR approach is use of chemically-native proteins and membrane components. The conventional REDOR pulse sequence with 100 kHz (2)H π pulses is robust with respect to the (2)H quadrupolar anisotropy. The (2)H T1's are comparable to the longer dephasing times (τ's) and this leads to exponential rather than sigmoidal REDOR buildups. The (13)CO-(2)H buildups are well-fitted to A×(1-e(-γτ)) where A and γ are fitting parameters that are correlated as the fraction of molecules (A) with effective (13)CO-(2)H coupling d=3γ/2. The REDOR approach is applied to probe the membrane locations of the "fusion peptide" regions of the HIV gp41 and influenza virus hemagglutinin proteins which both catalyze joining of the viral and host cell membranes during initial infection of the cell. The HIV fusion peptide forms an intermolecular antiparallel β sheet and the REDOR data support major deeply-inserted and minor shallowly-inserted molecular populations. A significant fraction of the influenza fusion peptide molecules form a tight hairpin with antiparallel N- and C-α helices and the REDOR data support a single peptide population with a deeply-inserted N-helix. The shared feature of deep insertion of the β and α fusion peptide structures may be relevant for fusion catalysis via the resultant local perturbation of the membrane bilayer. Future applications of the REDOR approach may include samples that contain cell membrane extracts and use of lower temperatures and dynamic nuclear polarization to reduce data acquisition times.
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Affiliation(s)
- Lihui Jia
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, United States
| | - Shuang Liang
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, United States
| | - Kelly Sackett
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, United States
| | - Li Xie
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, United States
| | - Ujjayini Ghosh
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, United States
| | - David P Weliky
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, United States.
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24
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Chakraborty H, Tarafdar PK, Klapper DG, Lentz BR. Wild-type and mutant hemagglutinin fusion peptides alter bilayer structure as well as kinetics and activation thermodynamics of stalk and pore formation differently: mechanistic implications. Biophys J 2014; 105:2495-506. [PMID: 24314080 DOI: 10.1016/j.bpj.2013.10.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 10/04/2013] [Accepted: 10/09/2013] [Indexed: 02/02/2023] Open
Abstract
Viral fusion peptides are short N-terminal regions of type-1 viral fusion proteins that are critical for virus entry. Although the importance of viral fusion peptides in virus-cell membrane fusion is established, little is known about how they function. We report the effects of wild-type (WT) hemagglutinin (HA) fusion peptide and its G1S, G1V, and W14A mutants on the kinetics of poly(ethylene glycol)(PEG)-mediated fusion of small unilamellar vesicles composed of dioleoylphosphatidylcholine, dioleoylphosphatidylethanolamine, sphingomyelin, and cholesterol (molar ratio of 35:30:15:20). Time courses of lipid mixing, content mixing, and content leakage were obtained using fluorescence assays at multiple temperatures and analyzed globally using either a two-step or three-step sequential ensemble model of the fusion process to obtain the rate constant and activation thermodynamics of each step. We also monitored the influence of peptides on bilayer interfacial order, acyl chain order, bilayer free volume, and water penetration. All these data were considered in terms of a recently published mechanistic model for the thermodynamic transition states for each step of the fusion process. We propose that WT peptide catalyzes Step 1 by occupying bilayer regions vacated by acyl chains that protrude into interbilayer space to form the Step 1 transition state. It also uniquely contributes a positive intrinsic curvature to hemi-fused leaflets to eliminate Step 2 and catalyzes Step 3 by destabilizing the highly stressed edges of the hemi-fused microstructures that dominate the ensemble of the intermediate state directly preceding fusion pore formation. Similar arguments explain the catalytic and inhibitory properties of the mutant peptides and support the hypothesis that the membrane-contacting fusion peptide of HA fusion protein is key to its catalytic activity.
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Affiliation(s)
- Hirak Chakraborty
- Department of Biochemistry and Biophysics & Program in Molecular and Cellular Biophysics, University of North Carolina at Chapel Hill, North Carolina 27599-7260
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25
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Lai AL, Freed JH. HIV gp41 fusion peptide increases membrane ordering in a cholesterol-dependent fashion. Biophys J 2014; 106:172-81. [PMID: 24411249 DOI: 10.1016/j.bpj.2013.11.027] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 10/11/2013] [Accepted: 11/13/2013] [Indexed: 10/25/2022] Open
Abstract
Fusion between viral envelopes and host cell membranes, which is mediated by special glycoproteins anchored on the viral membrane, is required for HIV viral entry and infection. The HIV gp41 fusion peptide (FP), which initiates membrane fusion, adopts either an α-helical or β-sheeted structure depending on the cholesterol concentration. We used phosphocholine spin labels on the lipid headgroup and different positions on the acyl chain to detect its perturbation on lipid bilayers containing different cholesterol concentrations by electron-spin resonance. Our findings were as follows. 1), gp41 FP affects the lipid order in the same manner as previously shown for influenza hemagglutinin FP, i.e., it has a cooperative effect versus the peptide/lipid ratio, supporting our hypothesis that membrane ordering is a common prerequisite for viral membrane fusion. 2), gp41 FP induces membrane ordering in all lipid compositions studied, whereas a nonfusion mutant FP perturbs lipid order to a significantly smaller extent. 3), In high-cholesterol-containing lipid bilayers, where gp41 FP is in the β-aggregation conformation, its effect on the lipid ordering reaches deeper into the bilayer. The different extent to which the two conformers perturb is correlated with their fusogenicity. The possible role of the two conformers in membrane fusion is discussed.
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Affiliation(s)
- Alex L Lai
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York.
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26
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Eddy MT, Yu TY. Membranes, peptides, and disease: unraveling the mechanisms of viral proteins with solid state nuclear magnetic resonance spectroscopy. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2014; 61-62:1-7. [PMID: 24837131 DOI: 10.1016/j.ssnmr.2014.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 06/03/2023]
Abstract
The interplay between peptides and lipid bilayers drives crucial biological processes. For example, a critical step in the replication cycle of enveloped viruses is the fusion of the viral membrane and host cell endosomal membrane, and these fusion events are controlled by viral fusion peptides. Thus such membrane-interacting peptides are of considerable interest as potential pharmacological targets. Deeper insight is needed into the mechanisms by which fusion peptides and other viral peptides modulate their surrounding membrane environment, and also how the particular membrane environment modulates the structure and activity of these peptides. An important step toward understanding these processes is to characterize the structure of viral peptides in environments that are as biologically relevant as possible. Solid state nuclear magnetic resonance (ssNMR) is uniquely well suited to provide atomic level information on the structure and dynamics of both membrane-associated peptides as well as the lipid bilayer itself; further ssNMR can delineate the contribution of specific membrane components, such as cholesterol, or changing cellular conditions, such as a decrease in pH on membrane-associating peptides. This paper highlights recent advances in the study of three types of membrane associated viral peptides by ssNMR to illustrate the more general power of ssNMR in addressing important biological questions involving membrane proteins.
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Affiliation(s)
- Matthew T Eddy
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Tsyr-Yan Yu
- Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1 Sec. 4. Rooservelt Rd., Taipei, 10617, Taiwan.
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27
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Apellániz B, Huarte N, Largo E, Nieva JL. The three lives of viral fusion peptides. Chem Phys Lipids 2014; 181:40-55. [PMID: 24704587 PMCID: PMC4061400 DOI: 10.1016/j.chemphyslip.2014.03.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/19/2014] [Accepted: 03/20/2014] [Indexed: 02/07/2023]
Abstract
The presence of a fusion peptide (FP) is a hallmark of viral fusion glycoproteins. Structure–function relationships underlying FP conservation remain greatly unknown. FPs establish interactions satisfying their folding within pre-fusion glycoproteins. Upon fusion activation FPs insert into and restructure target membranes. FPs can finally combine with transmembrane domains to form integral membrane bundles.
Fusion peptides comprise conserved hydrophobic domains absolutely required for the fusogenic activity of glycoproteins from divergent virus families. After 30 years of intensive research efforts, the structures and functions underlying their high degree of sequence conservation are not fully elucidated. The long-hydrophobic viral fusion peptide (VFP) sequences are structurally constrained to access three successive states after biogenesis. Firstly, the VFP sequence must fulfill the set of native interactions required for (meta) stable folding within the globular ectodomains of glycoprotein complexes. Secondly, at the onset of the fusion process, they get transferred into the target cell membrane and adopt specific conformations therein. According to commonly accepted mechanistic models, membrane-bound states of the VFP might promote the lipid bilayer remodeling required for virus-cell membrane merger. Finally, at least in some instances, several VFPs co-assemble with transmembrane anchors into membrane integral helical bundles, following a locking movement hypothetically coupled to fusion-pore expansion. Here we review different aspects of the three major states of the VFPs, including the functional assistance by other membrane-transferring glycoprotein regions, and discuss briefly their potential as targets for clinical intervention.
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Affiliation(s)
- Beatriz Apellániz
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Nerea Huarte
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - José L Nieva
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
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28
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Gabrys CM, Qiang W, Sun Y, Xie L, Schmick SD, Weliky DP. Solid-state nuclear magnetic resonance measurements of HIV fusion peptide 13CO to lipid 31P proximities support similar partially inserted membrane locations of the α helical and β sheet peptide structures. J Phys Chem A 2013; 117:9848-59. [PMID: 23418890 PMCID: PMC3932798 DOI: 10.1021/jp312845w] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fusion of the human immunodeficiency virus (HIV) membrane and the host cell membrane is an initial step of infection of the host cell. Fusion is catalyzed by gp41, which is an integral membrane protein of HIV. The fusion peptide (FP) is the ∼25 N-terminal residues of gp41 and is a domain of gp41 that plays a key role in fusion catalysis likely through interaction with the host cell membrane. Much of our understanding of the FP domain has been accomplished with studies of "HFP", i.e., a ∼25-residue peptide composed of the FP sequence but lacking the rest of gp41. HFP catalyzes fusion between membrane vesicles and serves as a model system to understand fusion catalysis. HFP binds to membranes and the membrane location of HFP is likely a significant determinant of fusion catalysis perhaps because the consequent membrane perturbation reduces the fusion activation energy. In the present study, many HFPs were synthesized and differed in the residue position that was (13)CO backbone labeled. Samples were then prepared that each contained a singly (13)CO labeled HFP incorporated into membranes that lacked cholesterol. HFP had distinct molecular populations with either α helical or oligomeric β sheet structure. Proximity between the HFP (13)CO nuclei and (31)P nuclei in the membrane headgroups was probed by solid-state NMR (SSNMR) rotational-echo double-resonance (REDOR) measurements. For many samples, there were distinct (13)CO shifts for the α helical and β sheet structures so that the proximities to (31)P nuclei could be determined for each structure. Data from several differently labeled HFPs were then incorporated into a membrane location model for the particular structure. In addition to the (13)CO labeled residue position, the HFPs also differed in sequence and/or chemical structure. "HFPmn" was a linear peptide that contained the 23 N-terminal residues of gp41. "HFPmn_V2E" contained the V2E mutation that for HIV leads to greatly reduced extent of fusion and infection. The present study shows that HFPmn_V2E induces much less vesicle fusion than HFPmn. "HFPtr" contained three strands with HFPmn sequence that were chemically cross-linked near their C-termini. HFPtr mimics the trimeric topology of gp41 and induces much more rapid and extensive vesicle fusion than HFPmn. For HFPmn and HFPtr, well-resolved α and β peaks were observed for A6-, L9-, and L12-labeled samples. For each of these samples, there were similar HFP (13)CO to lipid (31)P proximities in the α and β structures, which evidenced comparable membrane locations of the HFP in either structure including insertion into a single membrane leaflet. The data were also consistent with deeper insertion of HFPtr relative to HFPmn in both the α and β structures. The results supported a strong correlation between the membrane insertion depth of the HFP and its fusogenicity. More generally, the results supported membrane location of the HFP as an important determinant of its fusogenicity. The deep insertion of HFPtr in both the α and β structures provides the most relevant membrane location of the FP for HIV gp41-catalyzed membrane fusion because HIV gp41 is natively trimeric. Well-resolved α and β signals were observed in the HFPmn_V2E samples with L9- and L12- but not A6-labeling. The α signals were much more dominant for L9- and L12-labeled HFPmn_V2E than the corresponding HFPmn or HFPtr. The structural model for the less fusogenic HFPmn_V2E includes a shorter helix and less membrane insertion than either HFPmn or HFPtr. This greater helical population and different helical structure and membrane location could result in less membrane perturbation and lower fusogenicity of HFPmn_V2E and suggest that the β sheet fusion peptide is the most functionally relevant structure of HFPmn, HFPtr, and gp41.
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Affiliation(s)
- Charles M. Gabrys
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
| | - Wei Qiang
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
| | - Yan Sun
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
| | - Li Xie
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
| | - Scott D. Schmick
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
| | - David P. Weliky
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824
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29
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Biological Water Dynamics and Entropy: A Biophysical Origin of Cancer and Other Diseases. ENTROPY 2013. [DOI: 10.3390/e15093822] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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30
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Larsson P, Kasson PM. Lipid tail protrusion in simulations predicts fusogenic activity of influenza fusion peptide mutants and conformational models. PLoS Comput Biol 2013; 9:e1002950. [PMID: 23505359 PMCID: PMC3591293 DOI: 10.1371/journal.pcbi.1002950] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/11/2013] [Indexed: 11/18/2022] Open
Abstract
Fusion peptides from influenza hemagglutinin act on membranes to promote membrane fusion, but the mechanism by which they do so remains unknown. Recent theoretical work has suggested that contact of protruding lipid tails may be an important feature of the transition state for membrane fusion. If this is so, then influenza fusion peptides would be expected to promote tail protrusion in proportion to the ability of the corresponding full-length hemagglutinin to drive lipid mixing in fusion assays. We have performed molecular dynamics simulations of influenza fusion peptides in lipid bilayers, comparing the X-31 influenza strain against a series of N-terminal mutants. As hypothesized, the probability of lipid tail protrusion correlates well with the lipid mixing rate induced by each mutant. This supports the conclusion that tail protrusion is important to the transition state for fusion. Furthermore, it suggests that tail protrusion can be used to examine how fusion peptides might interact with membranes to promote fusion. Previous models for native influenza fusion peptide structure in membranes include a kinked helix, a straight helix, and a helical hairpin. Our simulations visit each of these conformations. Thus, the free energy differences between each are likely low enough that specifics of the membrane environment and peptide construct may be sufficient to modulate the equilibrium between them. However, the kinked helix promotes lipid tail protrusion in our simulations much more strongly than the other two structures. We therefore predict that the kinked helix is the most fusogenic of these three conformations. Membrane fusion is a common process critical to both cellular function and infection by enveloped viruses. Influenza is a particularly useful model system for studying fusion because the fusion reaction is accomplished by a single protein, hemagglutinin. Furthermore, mutations to the membrane-inserted portion of hemagglutinin have been identified that do not detectably alter the rest of the protein but can either arrest fusion halfway or block it entirely. For influenza at least, it seems that the membrane-inserted hemagglutinin peptide plays a critical role in promoting fusion, perhaps by increasing the local disorder of lipid bilayers. However, we lack a mechanistic understanding sufficient to predict the activity of fusion peptide mutants from their sequence. Here, we have used lipid tail protrusion as a way to measure how much fusion peptides disorder their surrounding bilayer; we see a strong relationship between lipid tail protrusion and the ability of fusion peptide mutants to promote lipid mixing between membranes. Our simulations also predict that this lipid tail protrusion is much more common when the peptides adopt a kinked helix structure than when they are straight or hairpin-like. We therefore hypothesize that, while all three types of structure likely undergo conformational exchange, the kinked helix structure is most active in promoting fusion.
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Affiliation(s)
- Per Larsson
- Departments of Molecular Physiology and Biological Physics and of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States of America
| | - Peter M. Kasson
- Departments of Molecular Physiology and Biological Physics and of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Promsri S, Ullmann GM, Hannongbua S. Molecular dynamics simulation of HIV-1 fusion domain-membrane complexes: Insight into the N-terminal gp41 fusion mechanism. Biophys Chem 2012; 170:9-16. [DOI: 10.1016/j.bpc.2012.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 06/24/2012] [Accepted: 07/09/2012] [Indexed: 11/26/2022]
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Haque ME, Chakraborty H, Koklic T, Komatsu H, Axelsen PH, Lentz BR. Hemagglutinin fusion peptide mutants in model membranes: structural properties, membrane physical properties, and PEG-mediated fusion. Biophys J 2011; 101:1095-104. [PMID: 21889446 DOI: 10.1016/j.bpj.2011.07.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 06/23/2011] [Accepted: 07/08/2011] [Indexed: 10/17/2022] Open
Abstract
While the importance of viral fusion peptides (e.g., hemagglutinin (HA) and gp41) in virus-cell membrane fusion is established, it is unclear how these peptides enhance membrane fusion, especially at low peptide/lipid ratios for which the peptides are not lytic. We assayed wild-type HA fusion peptide and two mutants, G1E and G13L, for their effects on the bilayer structure of 1,2-dioleoyl-3-sn-phosphatidylcholine/1,2-dioleoyl-3-sn-phosphatidylethanolamine/Sphingomyelin/Cholesterol (35:30:15:20) membranes, their structures in the lipid bilayer, and their effects on membrane fusion. All peptides bound to highly curved vesicles, but fusion was triggered only in the presence of poly(ethylene glycol). At low (1:200) peptide/lipid ratios, wild-type peptide enhanced remarkably the extent of content mixing and leakage along with the rate constants for these processes, and significantly enhanced the bilayer interior packing and filled the membrane free volume. The mutants caused no change in contents mixing or interior packing. Circular dichroism, polarized-attenuated total-internal-reflection Fourier-transform infrared spectroscopy measurements, and membrane perturbation measurements all conform to the inverted-V model for the structure of wild-type HA peptide. Similar measurements suggest that the G13L mutant adopts a less helical conformation in which the N-terminus moves closer to the bilayer interface, thus disrupting the V-structure. The G1E peptide barely perturbs the bilayer and may locate slightly above the interface. Fusion measurements suggest that the wild-type peptide promotes conversion of the stalk to an expanded trans-membrane contact intermediate through its ability to occupy hydrophobic space in a trans-membrane contact structure. While wild-type peptide increases the rate of initial intermediate and final pore formation, our results do not speak to the mechanisms for these effects, but they do leave open the possibility that it stabilizes the transition states for these events.
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Affiliation(s)
- Md Emdadul Haque
- Department of Biochemistry and Biophysics and Program in Cellular and Molecular Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Majumder R, Liang X, Quinn-Allen MA, Kane WH, Lentz BR. Modulation of prothrombinase assembly and activity by phosphatidylethanolamine. J Biol Chem 2011; 286:35535-35542. [PMID: 21859710 DOI: 10.1074/jbc.m111.260141] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Constituents of platelet membranes regulate the activity of the prothrombinase complex. We demonstrate that membranes containing phosphatidylcholine and phosphatidylethanolamine (PE) bind factor Va with high affinity (K(d) = ∼10 nm) in the absence of phosphatidylserine (PS). These membranes support formation of a 60-70% functional prothrombinase complex at saturating factor Va concentrations. Although reduced interfacial packing does contribute to factor Va binding in the absence of PS, it does not correlate with the enhanced activity of the Xa-Va complex assembled on PE-containing membranes. Instead, specific protein-PE interactions appear to contribute to the effects of PE. In support of this, soluble C6PE binds to recombinant factor Va(2) (K(d) = ∼6.5 μm) and to factor Xa (K(d) = ∼91 μm). C6PE and C6PS binding sites of factor Xa are specific, distinct, and linked, because binding of one lipid enhances the binding and activity effects of the other. C6PE triggers assembly (K(d)(app) = ∼40 nm) of a partially active prothrombinase complex between factor Xa and factor Va(2), compared with K(d)(app) for C6PS ∼2 nm. These findings provide new insights into the possible synergistic roles of platelet PE and PS in regulating thrombin formation, particularly when exposed membrane PS may be limiting.
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Affiliation(s)
- Rinku Majumder
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260.
| | - Xiaoe Liang
- Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27702-3656
| | - Mary Ann Quinn-Allen
- Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27702-3656
| | - William H Kane
- Division of Hematology, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27702-3656.
| | - Barry R Lentz
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7260.
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Mondal Roy S, Sarkar M. Membrane fusion induced by small molecules and ions. J Lipids 2011; 2011:528784. [PMID: 21660306 PMCID: PMC3108104 DOI: 10.1155/2011/528784] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/28/2011] [Accepted: 02/25/2011] [Indexed: 01/11/2023] Open
Abstract
Membrane fusion is a key event in many biological processes. These processes are controlled by various fusogenic agents of which proteins and peptides from the principal group. The fusion process is characterized by three major steps, namely, inter membrane contact, lipid mixing forming the intermediate step, pore opening and finally mixing of inner contents of the cells/vesicles. These steps are governed by energy barriers, which need to be overcome to complete fusion. Structural reorganization of big molecules like proteins/peptides, supplies the required driving force to overcome the energy barrier of the different intermediate steps. Small molecules/ions do not share this advantage. Hence fusion induced by small molecules/ions is expected to be different from that induced by proteins/peptides. Although several reviews exist on membrane fusion, no recent review is devoted solely to small moleculs/ions induced membrane fusion. Here we intend to present, how a variety of small molecules/ions act as independent fusogens. The detailed mechanism of some are well understood but for many it is still an unanswered question. Clearer understanding of how a particular small molecule can control fusion will open up a vista to use these moleucles instead of proteins/peptides to induce fusion both in vivo and in vitro fusion processes.
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Affiliation(s)
- Sutapa Mondal Roy
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata 700064, India
| | - Munna Sarkar
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata 700064, India
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Grasnick D, Sternberg U, Strandberg E, Wadhwani P, Ulrich AS. Irregular structure of the HIV fusion peptide in membranes demonstrated by solid-state NMR and MD simulations. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:529-43. [PMID: 21274707 DOI: 10.1007/s00249-011-0676-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 12/21/2010] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
To better understand peptide-induced membrane fusion at a molecular level, we set out to determine the structure of the fusogenic peptide FP23 from the HIV-1 protein gp41 when bound to a lipid bilayer. An established solid-state (19)F nuclear magnetic resonance (NMR) approach was used to collect local orientational constraints from a series of CF(3)-phenylglycine-labeled peptide analogues in macroscopically aligned membranes. Fusion assays showed that these (19)F-labels did not significantly affect peptide function. The NMR spectra were characteristic of well-behaved samples, without any signs of heterogeneity or peptide aggregation at 1:300 in 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC). We can conclude from these NMR data that FP23 has a well-defined (time-averaged) conformation and undergoes lateral diffusion in the bilayer plane, presumably as a monomer or small oligomer. Attempts to evaluate its conformation in terms of various secondary structures, however, showed that FP23 does not form any type of regular helix or β-strand. Therefore, all-atom molecular dynamics (MD) simulations were carried out using the orientational NMR constraints as pseudo-forces to drive the peptide into a stable alignment and structure. The resulting picture suggests that FP23 can adopt multiple β-turns and insert obliquely into the membrane. Such irregular conformation explains why the structure of the fusion peptide could not be reliably determined by any biophysical method so far.
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Affiliation(s)
- Dorit Grasnick
- Karlsruhe Institute of Technology, Institute of Organic Chemistry and CFN, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
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Tristram-Nagle S, Chan R, Kooijman E, Uppamoochikkal P, Qiang W, Weliky DP, Nagle JF. HIV fusion peptide penetrates, disorders, and softens T-cell membrane mimics. J Mol Biol 2010; 402:139-53. [PMID: 20655315 DOI: 10.1016/j.jmb.2010.07.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 07/12/2010] [Accepted: 07/13/2010] [Indexed: 02/01/2023]
Abstract
This work investigates the interaction of N-terminal gp41 fusion peptide (FP) of human immunodeficiency virus type 1 (HIV-1) with model membranes in order to elucidate how FP leads to fusion of HIV and T-cell membranes. FP constructs were (i) wild-type FP23 (23 N-terminal amino acids of gp41), (ii) water-soluble monomeric FP that adds six lysines on the C-terminus of FP23 (FPwsm), and (iii) the C-terminus covalently linked trimeric version (FPtri) of FPwsm. Model membranes were (i) LM3 (a T-cell mimic), (ii) 1,2-dioleoyl-sn-glycero-3-phosphocholine, (iii) 1,2-dioleoyl-sn-glycero-3-phosphocholine/30 mol% cholesterol, (iv) 1,2-dierucoyl-sn-glycero-3-phosphocholine, and (v) 1,2-dierucoyl-sn-glycero-3-phosphocholine/30 mol% cholesterol. Diffuse synchrotron low-angle x-ray scattering from fully hydrated samples, supplemented by volumetric data, showed that FP23 and FPtri penetrate into the hydrocarbon region and cause membranes to thin. Depth of penetration appears to depend upon a complex combination of factors including bilayer thickness, presence of cholesterol, and electrostatics. X-ray data showed an increase in curvature in hexagonal phase 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, which further indicates that FP23 penetrates into the hydrocarbon region rather than residing in the interfacial headgroup region. Low-angle x-ray scattering data also yielded the bending modulus K(C), a measure of membrane stiffness, and wide-angle x-ray scattering yielded the S(xray) orientational order parameter. Both FP23 and FPtri decreased K(C) and S(xray) considerably, while the weak effect of FPwsm suggests that it did not partition strongly into LM3 model membranes. Our results are consistent with the HIV FP disordering and softening the T-cell membrane, thereby lowering the activation energy for viral membrane fusion.
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Affiliation(s)
- Stephanie Tristram-Nagle
- Biological Physics Group, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
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Mondal S, Sarkar M. Non-Steroidal Anti-Inflammatory Drug Induced Membrane Fusion: Concentration and Temperature Effects. J Phys Chem B 2009; 113:16323-31. [DOI: 10.1021/jp9069527] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Sutapa Mondal
- Chemical Sciences Division, Saha Institute of Nuclear Physics 1/AF, Bidhannagar, Kolkata-700064, India
| | - Munna Sarkar
- Chemical Sciences Division, Saha Institute of Nuclear Physics 1/AF, Bidhannagar, Kolkata-700064, India
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Ge M, Freed JH. Fusion peptide from influenza hemagglutinin increases membrane surface order: an electron-spin resonance study. Biophys J 2009; 96:4925-34. [PMID: 19527651 DOI: 10.1016/j.bpj.2009.04.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 02/27/2009] [Accepted: 04/06/2009] [Indexed: 11/29/2022] Open
Abstract
A spin-labeling study of interactions of a fusion peptide from the hemagglutinin of the influenza virus, wt20, and a fusion-inactive mutant DeltaG1 with dimyristoylphosphatidylcholine (DMPC) and 1-palmitoyl-2-oleoyl-phosphatdylcholine bilayers was performed. We found that upon binding of wt20, the ordering of headgroups and the ordering of acyl chains near the headgroup increased significantly, in a manner consistent with a cooperative phenomenon. However, changes in the order at the end of the acyl chains were negligible. The ordering effect of wt20 on the headgroup was much stronger at pH 5 than at pH 7. No effect of DeltaG1 binding on the order of bilayers was evident. We also found that 1-palmitoyl-2-hydroxyl phosphatidylcholine, a membrane-fusion inhibitor, decreased the ordering of DMPC headgroups, whereas arachidonic acid, a membrane-fusion promoter, increased the ordering of DMPC headgroups. These results suggest that increases in headgroup ordering may be important for membrane fusion. We propose that upon binding of wt20, which is known to affect only the outer leaflet of the bilayer, this outer leaflet becomes more ordered, and thus more solid-like. Then the coupling between the hardened outer leaflet and the softer inner leaflet generates bending stresses in the bilayer, which tend to increase the negative curvature of the bilayer. We suggest that the increased ordering in the headgroup region enhances dipolar interactions and lowers electrostatic energy, which may provide an energy source for membrane fusion. Possible roles of bending stresses in promoting membrane fusion are discussed.
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Affiliation(s)
- Mingtao Ge
- National Biomedical Center for Advanced ESR Technology, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 15853, USA
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40
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A strong correlation between fusogenicity and membrane insertion depth of the HIV fusion peptide. Proc Natl Acad Sci U S A 2009; 106:15314-9. [PMID: 19706388 DOI: 10.1073/pnas.0907360106] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fusion between the membrane of HIV and the membrane of a host cell is a crucial step in HIV infection and is catalyzed by the binding of the fusion peptide domain (HFP) of the HIV gp41 protein to the host cell membrane. The HFP by itself induces vesicle fusion and is a useful model system to understand the fusion peptide/host cell membrane interaction. This article reports an experimental correlation between the membrane locations of different HFP constructs and their fusogenicities. The constructs were the HFP monomer with Val-2 to Glu-2 mutation (HFPmn_mut), wild type HFP monomer (HFPmn), and wild type HFP trimer (HFPtr). All constructs have predominant beta sheet structure in membranes with physiologically relevant cholesterol content. HFPmn_mut does not fuse vesicles, HFPmn has moderate fusion rate, and HFPtr has the putative oligomerization state of HIV gp41 and a very rapid fusion rate. The HFP membrane locations were probed with solid-state NMR measurements of distances between labeled carbonyl ((13)CO) nuclei in the HFP backbone and lipid nuclei in the surface or interior regions of the membrane bilayer. HFPmn_mut is located at the membrane surface, HFPmn is inserted into a single membrane leaflet, and HFPtr is the most deeply inserted construct with contact with the center of the membrane. These results show a clear positive correlation between the insertion depths and the fusion activities of the HFP constructs. Other disease-causing enveloped viruses contain fusion peptides and this correlation may be a general structure-function model for these peptides.
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41
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Qiang W, Weliky DP. HIV fusion peptide and its cross-linked oligomers: efficient syntheses, significance of the trimer in fusion activity, correlation of beta strand conformation with membrane cholesterol, and proximity to lipid headgroups. Biochemistry 2009; 48:289-301. [PMID: 19093835 DOI: 10.1021/bi8015668] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
For enveloped viruses such as HIV, an approximately 20-residue N-terminal fusion peptide domain in the envelope protein binds to target cell membranes and plays a key role in fusion between the viral and cellular membranes during infection. The chemically synthesized HIV fusion peptide (HFP) catalyzes fusion between membrane vesicles and is a useful model system for understanding some aspects of HIV fusion. Previous studies have shown a common trimeric state for the envelope protein from several different viruses, including HIV, and in this study, practical high-yield syntheses are reported for HFP monomer (HFPmn) and chemically cross-linked HFP dimer (HFPdm), trimer (HFPtr), and tetramer (HFPte). The vesicle fusion rates per strand were ordered as follows: HFPmn < HFPdm < HFPtr approximately HFPte. This suggested that HFPtr is the smallest catalytically efficient oligomer. Solid-state NMR measurements of (13)CO chemical shifts were carried out in constructs labeled at either Ala-6 or Ala-15. For all constructs associated with cholesterol-containing membranes, the chemical shifts of both residues correlated with beta strand conformation while association with membranes without cholesterol resulted in a mixture of helical and beta strand conformations. The dependence of fusion rate on oligomer size is independent of membrane cholesterol content, so one interpretation of the data is fusion activity of both helical and beta strand conformations. Membrane location may be a determinant of fusion activity, and for all constructs in both conformations, a large fraction of the Ala-15 (13)CO groups were 5-6 A from the (31)P atoms in the lipid headgroups, while the Ala-6 (13)CO groups were more distant.
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Affiliation(s)
- Wei Qiang
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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Laufer SD, Restle T. Peptide-mediated cellular delivery of oligonucleotide-based therapeutics in vitro: quantitative evaluation of overall efficacy employing easy to handle reporter systems. Curr Pharm Des 2009; 14:3637-55. [PMID: 19075740 PMCID: PMC2778081 DOI: 10.2174/138161208786898806] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Cellular uptake of therapeutic oligonucleotides and subsequent intracellular trafficking to their target sites represents the major technical hurdle for the biological effectiveness of these potential drugs. Accordingly, laboratories worldwide focus on the development of suitable delivery systems. Among the different available non-viral systems like cationic polymers, cationic liposomes and polymeric nanoparticles, cell-penetrating peptides (CPPs) represent an attractive concept to bypass the problem of poor membrane permeability of these charged macromolecules. While uptake per se in most cases does not represent the main obstacle of nucleic acid delivery in vitro, it becomes increasingly apparent that intracellular trafficking is the bottleneck. As a consequence, in order to optimize a given delivery system, a side-by-side analysis of nucleic acid cargo internalized and the corresponding biological effect is required to determine the overall efficacy. In this review, we will concentrate on peptide-mediated delivery of siRNAs and steric block oligonucleotides and discuss different methods for quantitative assessment of the amount of cargo taken up and how to correlate those numbers with biological effects by applying easy to handle reporter systems. To illustrate current limitations of non-viral nucleic acid delivery systems, we present own data as an example and discuss options of how to enhance trafficking of molecules entrapped in cellular compartments.
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Affiliation(s)
- S D Laufer
- Institut für Molekulare Medizin, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Chakraborty H, Mondal S, Sarkar M. Membrane fusion: A new function of non steroidal anti-inflammatory drugs. Biophys Chem 2008; 137:28-34. [DOI: 10.1016/j.bpc.2008.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 06/16/2008] [Accepted: 06/16/2008] [Indexed: 01/11/2023]
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Qiang W, Bodner ML, Weliky DP. Solid-state NMR spectroscopy of human immunodeficiency virus fusion peptides associated with host-cell-like membranes: 2D correlation spectra and distance measurements support a fully extended conformation and models for specific antiparallel strand registries. J Am Chem Soc 2008; 130:5459-71. [PMID: 18370385 DOI: 10.1021/ja077302m] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human immunodeficiency virus (HIV) is "enveloped" by a membrane, and infection of a host cell begins with fusion between viral and target cell membranes. Fusion is catalyzed by the HIV gp41 protein which contains a functionally critical approximately 20-residue apolar "fusion peptide" (HFP) that associates with target cell membranes. In this study, chemically synthesized HFPs were associated with host-cell-like membranes and had "scatter-uniform" labeling (SUL), that is, only one residue of each amino acid type was U-(13)C, (15)N labeled. For the first sixteen HFP residues, an unambiguous (13)C chemical shift assignment was derived from 2D (13)C/(13)C correlation spectra with short mixing times, and the shifts were consistent with continuous beta-strand conformation. (13)C-(13)C contacts between residues on adjacent strands were derived from correlation spectra with long mixing times and suggested close proximity of the following residues: Ala-6/Gly-10, Ala-6/Phe-11, and Ile-4/Gly-13. Specific antiparallel beta-strand registries were further tested using a set of HFPs that were (13)CO-labeled at Ala-14 and (15)N-labeled at either Val-2, Gly-3, Ile-4, or Gly-5. The solid-state NMR data were fit with 50-60% population of antiparallel HFP with either Ala-14/Gly-3 or Ala-14/Ile-4 registries and 40-50% population of structures not specified by the NMR experiments. The first two registries correlated with intermolecular hydrogen bonding of 15-16 apolar N-terminal residues and this hydrogen-bonding pattern would be consistent with a predominant location of these residues in the hydrophobic membrane interior. To our knowledge, these results provide the first residue-specific structural models for membrane-associated HFP in its beta-strand conformation.
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Affiliation(s)
- Wei Qiang
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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Bodner ML, Gabrys CM, Struppe JO, Weliky DP. C13–C13 and N15–C13 correlation spectroscopy of membrane-associated and uniformly labeled human immunodeficiency virus and influenza fusion peptides: Amino acid-type assignments and evidence for multiple conformations. J Chem Phys 2008; 128:052319. [DOI: 10.1063/1.2829984] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Barz B, Wong TC, Kosztin I. Membrane curvature and surface area per lipid affect the conformation and oligomeric state of HIV-1 fusion peptide: a combined FTIR and MD simulation study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1778:945-53. [PMID: 18177732 DOI: 10.1016/j.bbamem.2007.11.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 11/19/2007] [Accepted: 11/21/2007] [Indexed: 11/29/2022]
Abstract
Fourier-transformed infrared spectroscopy (FTIR) and molecular dynamics (MD) simulation results are presented to support our hypothesis that the conformation and the oligomeric state of the HIV-1 gp41 fusion domain or fusion peptide (gp41-FP) are determined by the membrane surface area per lipid (APL), which is affected by the membrane curvature. FTIR of the gp41-FP in the Aerosol-OT (AOT) reversed micellar system showed that as APL decreases from approximately 50 to 35 A2 by varying the AOT/water ratio, the FP changes from the monomeric alpha-helical to the oligomeric beta-sheet structure. MD simulations in POPE lipid bilayer systems showed that as the APL decreases by applying a negative surface tension, helical monomers start to unfold into turn-like structures. Furthermore, an increase in the applied lateral pressure during nonequilibrium MD simulations favored the formation of beta-sheet structure. These results provide better insight into the relationship between the structures of the gp41-FP and the membrane, which is essential in understanding the membrane fusion process. The implication of the results of this work on what is the fusogenic structure of the HIV-1 FP is discussed.
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Affiliation(s)
- Bogdan Barz
- Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211, USA
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Haque ME, Grasso D, Spremulli LL. The interaction of mammalian mitochondrial translational initiation factor 3 with ribosomes: evolution of terminal extensions in IF3mt. Nucleic Acids Res 2007; 36:589-97. [PMID: 18056078 PMCID: PMC2241858 DOI: 10.1093/nar/gkm1072] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mammalian mitochondrial initiation factor 3 (IF3mt) has a central region with homology to bacterial IF3. This homology region is preceded by an N-terminal extension and followed by a C-terminal extension. The role of these extensions on the binding of IF3mt to mitochondrial small ribosomal subunits (28S) was studied using derivatives in which the extensions had been deleted. The Kd for the binding of IF3mt to 28S subunits is ∼30 nM. Removal of either the N- or C-terminal extension has almost no effect on this value. IF3mt has very weak interactions with the large subunit of the mitochondrial ribosome (39S) (Kd = 1.5 μM). However, deletion of the extensions results in derivatives with significant affinity for 39S subunits (Kd = 0.12−0.25 μM). IF3mt does not bind 55S monosomes, while the deletion derivative binds slightly to these particles. IF3mt is very effective in dissociating 55S ribosomes. Removal of the N-terminal extension has little effect on this activity. However, removal of the C-terminal extension leads to a complex dissociation pattern due to the high affinity of this derivative for 39S subunits. These data suggest that the extensions have evolved to ensure the proper dissociation of IF3mt from the 28S subunits upon 39S subunit joining.
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Affiliation(s)
- Md Emdadul Haque
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC-27599-3290, USA
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48
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Chien MP, Jiang S, Chang DK. The function of coreceptor as a basis for the kinetic dissection of HIV type 1 envelope protein-mediated cell fusion. FASEB J 2007; 22:1179-92. [PMID: 18032634 DOI: 10.1096/fj.07-9576com] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The function of HIV-1 HXB2 envelope (Env) glycoprotein (gp) was investigated by surface plasmon resonance and fluorescence imaging techniques. Strikingly, it was found that gp120 shedding requires the presence of the X4 coreceptor. A similar coreceptor requirement was observed for the membrane mixing and the Env recruitment on the cell surface. However, exposure and membrane penetration of the fusion peptide do not require X4 and occur within the first minute after incubation of Env with CD4 and/or X4. Analogously X4 was not required but enhanced binding of the fusion inhibitor. In contrast, bundle formation of the gp41 ectodomain, as monitored by NC-1, was accelerated by the presence of X4. The kinetics of these key post-Env binding events as determined in real time by fluorescence microscopic imaging, coupled with the differential coreceptor requirement, led to the proposition that gp120 shedding, which takes place from 1 to 10 min after engagement of receptor and coreceptor to Env, is a primary function of the coreceptor. The shedding of the surface subunits is needed for the subsequent processes including hemifusion, full fusion, and Env recruitment. The temporal order of these fusogenic steps allows construction of a refined model on the Env-mediated cell fusion event.
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Affiliation(s)
- Miao-Ping Chien
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, Republic of China
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49
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Qiang W, Yang J, Weliky DP. Solid-state nuclear magnetic resonance measurements of HIV fusion peptide to lipid distances reveal the intimate contact of beta strand peptide with membranes and the proximity of the Ala-14-Gly-16 region with lipid headgroups. Biochemistry 2007; 46:4997-5008. [PMID: 17417873 PMCID: PMC2631438 DOI: 10.1021/bi6024808] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human immunodeficiency virus (HIV) infection begins with fusion between viral and host cell membranes and is catalyzed by the HIV gp41 fusion protein. The approximately 20 N-terminal apolar residues of gp41 are called the HIV fusion peptide (HFP), interact with the host cell membrane, and play a key role in fusion. In this study, the membrane location of peptides which contained the HFP sequence (AVGIGALFLGFLGAAGSTMGARS) was probed in samples containing either only phospholipids or phospholipids and cholesterol. Four HFPs were examined which each contained 13CO labeling at three sequential residues between G5 and G16. The 13CO chemical shifts indicated that HFP had predominant beta strand conformation over the labeled residues in the samples. The internuclear distances between the HFP 13CO groups and the lipid 31P atoms were measured using solid-state nuclear magnetic resonance rotational-echo double-resonance experiments. The shortest 13CO-31P distances of 5-6 A were observed for HFP labeled between A14 and G16 and correlated with intimate association of beta strand HFP and membranes. These results were confirmed with measurements using HFPs singly labeled with 13CO at A6 or A14. To our knowledge, these data are the first measurements of distances between HIV fusion peptide nuclei and lipid P, and qualitative models of the membrane location of oligomeric beta strand HFP which are consistent with the experimental data are presented. Observation of intimate contact between beta strand HFP and membranes provides a rationale for further investigation of the relationship between structure and fusion activity for this conformation.
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Affiliation(s)
- Wei Qiang
- Department of Chemistry, Michigan State University, East Lansing, MI 48824
| | - Jun Yang
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195
| | - David P. Weliky
- Department of Chemistry, Michigan State University, East Lansing, MI 48824
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50
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Roux KH, Taylor KA. AIDS virus envelope spike structure. Curr Opin Struct Biol 2007; 17:244-52. [PMID: 17395457 DOI: 10.1016/j.sbi.2007.03.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 02/26/2007] [Accepted: 03/16/2007] [Indexed: 11/30/2022]
Abstract
The envelope (Env) spikes on HIV-1 and closely related SIV define the viral tropism, mediate the fusion process and are the prime target of the humoral response. Despite intensive efforts, Env has been slow to reveal its structural and functional secrets. Three gp120 subunits comprise the 'head' of Env and three gp41 subunits comprise the 'stalk' and other membrane-associated elements. The recent description of the core structure of unliganded (untriggered) gp120, compared to earlier CD4-liganded atomic structures, reveals dramatic conformational reorganization of the components and suggests a mechanism for the initiation of fusion. The structure of the key V3 loop, both in isolation and in association with the liganded core, helps define its role in fusion and as a prime target of neutralizing antibodies. Additional details are emerging regarding the structure of gp41 as it transitions from the preliganded configuration to the fusion intermediate (fusion-active or prehairpin intermediate) configuration, although much remains speculative. Recent advances in cryoelectron tomography are giving us the first glimpses of the overall three-dimensional structure of Env, which, when fitted with the available component atomic structures, provides new insights into the organization of the structural elements within the trimeric spike.
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Affiliation(s)
- Kenneth H Roux
- Department of Biological Science and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4370, USA.
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