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Ali T, Klein AN, McDonald K, Johansson L, Mukherjee PG, Hallbeck M, Doh-Ura K, Schatzl HM, Gilch S. Cellulose ether treatment inhibits amyloid beta aggregation, neuroinflammation and cognitive deficits in transgenic mouse model of Alzheimer's disease. J Neuroinflammation 2023; 20:177. [PMID: 37507761 PMCID: PMC10375631 DOI: 10.1186/s12974-023-02858-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 07/23/2023] [Indexed: 07/30/2023] Open
Abstract
Alzheimer's disease (AD) is an incurable, progressive and devastating neurodegenerative disease. Pathogenesis of AD is associated with the aggregation and accumulation of amyloid beta (Aβ), a major neurotoxic mediator that triggers neuroinflammation and memory impairment. Recently, we found that cellulose ether compounds (CEs) have beneficial effects against prion diseases by inhibiting protein misfolding and replication of prions, which share their replication mechanism with Aβ. CEs are FDA-approved safe additives in foods and pharmaceuticals. Herein, for the first time we determined the therapeutic effects of the representative CE (TC-5RW) in AD using in vitro and in vivo models. Our in vitro studies showed that TC-5RW inhibits Aβ aggregation, as well as neurotoxicity and immunoreactivity in Aβ-exposed human and murine neuroblastoma cells. In in vivo studies, for the first time we observed that single and weekly TC-5RW administration, respectively, improved memory functions of transgenic 5XFAD mouse model of AD. We further demonstrate that TC-5RW treatment of 5XFAD mice significantly inhibited Aβ oligomer and plaque burden and its associated neuroinflammation via regulating astrogliosis, microgliosis and proinflammatory mediator glial maturation factor beta (GMFβ). Additionally, we determined that TC-5RW reduced lipopolysaccharide-induced activated gliosis and GMFβ in vitro. In conclusion, our results demonstrate that CEs have therapeutic effects against Aβ pathologies and cognitive impairments, and direct, potent anti-inflammatory activity to rescue neuroinflammation. Therefore, these FDA-approved compounds are effective candidates for developing therapeutics for AD and related neurodegenerative diseases associated with protein misfolding.
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Affiliation(s)
- Tahir Ali
- Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
| | - Antonia N Klein
- Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Keegan McDonald
- Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Lovisa Johansson
- Department of Biomedical and Clinical Sciences (BKV), Linköping University, 58185, Linköping, Sweden
| | | | - Martin Hallbeck
- Department of Biomedical and Clinical Sciences (BKV), Linköping University, 58185, Linköping, Sweden
| | - Katsumi Doh-Ura
- Department of Neurochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Hermann M Schatzl
- Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Sabine Gilch
- Calgary Prion Research Unit, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
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2
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John T, Piantavigna S, Dealey TJA, Abel B, Risselada HJ, Martin LL. Lipid oxidation controls peptide self-assembly near membranes through a surface attraction mechanism. Chem Sci 2023; 14:3730-3741. [PMID: 37035708 PMCID: PMC10074436 DOI: 10.1039/d3sc00159h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/17/2023] [Indexed: 03/06/2023] Open
Abstract
The self-assembly of peptides into supramolecular structures has been linked to neurodegenerative diseases but has also been observed in functional roles. Peptides are physiologically exposed to crowded environments of biomacromolecules, and particularly cellular membrane lipids. Previous research has shown that membranes can both accelerate and inhibit peptide self-assembly. Here, we studied the impact of membrane models that mimic cellular oxidative stress and compared this to mammalian and bacterial membranes. Using molecular dynamics simulations and experiments, we propose a model that explains how changes in peptide-membrane binding, electrostatics, and peptide secondary structure stabilization determine the nature of peptide self-assembly. We explored the influence of zwitterionic (POPC), anionic (POPG) and oxidized (PazePC) phospholipids, as well as cholesterol, and mixtures thereof, on the self-assembly kinetics of the amyloid β (1-40) peptide (Aβ40), linked to Alzheimer's disease, and the amyloid-forming antimicrobial peptide uperin 3.5 (U3.5). We show that the presence of an oxidized lipid had similar effects on peptide self-assembly as the bacterial mimetic membrane. While Aβ40 fibril formation was accelerated, U3.5 aggregation was inhibited by the same lipids at the same peptide-to-lipid ratio. We attribute these findings and peptide-specific effects to differences in peptide-membrane adsorption with U3.5 being more strongly bound to the membrane surface and stabilized in an α-helical conformation compared to Aβ40. Different peptide-to-lipid ratios resulted in different effects. We found that electrostatic interactions are a primary driving force for peptide-membrane interaction, enabling us to propose a model for predicting how cellular changes might impact peptide self-assembly in vivo.
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Affiliation(s)
- Torsten John
- School of Chemistry, Monash University Clayton VIC 3800 Australia
- Leibniz Institute of Surface Engineering (IOM) Permoserstraße 15 04318 Leipzig Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Institute of Chemical Technology, Leipzig University Linnéstraße 3 04103 Leipzig Germany
| | | | - Tiara J A Dealey
- School of Chemistry, Monash University Clayton VIC 3800 Australia
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM) Permoserstraße 15 04318 Leipzig Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Institute of Chemical Technology, Leipzig University Linnéstraße 3 04103 Leipzig Germany
| | - Herre Jelger Risselada
- Leibniz Institute of Surface Engineering (IOM) Permoserstraße 15 04318 Leipzig Germany
- Institute for Theoretical Physics, Georg-August-Universität Göttingen Friedrich-Hund-Platz 1 37077 Göttingen Germany
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3
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Rahmaninejad H, Pace T, Chun BJ, Kekenes-Huskey PM. Crowding within synaptic junctions influences the degradation of nucleotides by CD39 and CD73 ectonucleotidases. Biophys J 2022; 121:309-318. [PMID: 34922916 PMCID: PMC8790186 DOI: 10.1016/j.bpj.2021.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/01/2021] [Accepted: 12/07/2021] [Indexed: 01/21/2023] Open
Abstract
Synapsed cells can communicate using exocytosed nucleotides like adenosine triphosphate (ATP). Ectonucleotidases localized to synaptic junctions degrade nucleotides into metabolites like adenosine monophosphate (AMP) or adenosine. Oftentimes nucleotide degradation occurs in a sequential manner, of which ATP degradation by CD39 and CD73 is a representative example. Here, CD39 first converts ATP and adenosine diphosphate (ADP) into AMP, after which AMP is dephosphorylated into adenosine by CD73. Hence, the concerted activity of CD39 and CD73 can help shape cellular responses to extracellular ATP. In a previous study, we demonstrated that coupled CD39 and CD73 activity within synapse-like junctions is strongly controlled by the enzymes' co-localization, their surface charge densities, and the electrostatic potential of the surrounding cell membranes. In this study, we demonstrate that crowders within synaptic junctions, which can include globular proteins like cytokines and membrane-bound proteins, impact coupled CD39 and CD73 ectonucleotidase activity and, in turn, the availability of intrasynapse ATP. Specifically, we developed a spatially explicit, reaction-diffusion model for the coupled conversion of ATP → AMP and AMP → adenosine in a model synaptic junction with crowders that is solved via the finite element method. Our modeling results suggest that the association rate for ATP to CD39 is strongly influenced by the density of intrasynaptic protein crowders, as increasing crowder density generally suppressed ATP association kinetics. Much of this suppression can be rationalized based on a loss of configurational entropy. The surface charges of crowders can further influence the association rate, with the surprising result that favorable crowder-nucleotide electrostatic interactions can yield CD39 association rates that are faster than crowder-free configurations. However, attractive crowder-nucleotide interactions decrease the rate and efficiency of adenosine production, which in turn increases the availability of ATP and AMP within the synapse relative to crowder-free configurations. These findings highlight how CD39 and CD73 ectonucleotidase activity, electrostatics, and crowding within synapses influence the availability of nucleotides for intercellular communication.
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Affiliation(s)
- Hadi Rahmaninejad
- Department of Physics, Virginia Tech, Blacksburg,Corresponding author
| | - Tom Pace
- Department of Cell & Molecular Physiology, Loyola University Chicago, Chicago,Corresponding author
| | - Byeong Jae Chun
- Department of Cell & Molecular Physiology, Loyola University Chicago, Chicago
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Antitumor Activity and Mechanism of Action of Hormonotoxin, an LHRH Analog Conjugated to Dermaseptin-B2, a Multifunctional Antimicrobial Peptide. Int J Mol Sci 2021; 22:ijms222111303. [PMID: 34768734 PMCID: PMC8582938 DOI: 10.3390/ijms222111303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/15/2022] Open
Abstract
Prostate cancer is the most common cancer in men. For patients with advanced or metastatic prostate cancer, available treatments can slow down its progression but cannot cure it. The development of innovative drugs resulting from the exploration of biodiversity could open new therapeutic alternatives. Dermaseptin-B2, a natural multifunctional antimicrobial peptide isolated from Amazonian frog skin, has been reported to possess antitumor activity. To improve its pharmacological properties and to decrease its peripheral toxicity and lethality we developed a hormonotoxin molecule composed of dermaseptin-B2 combined with d-Lys6-LHRH to target the LHRH receptor. This hormonotoxin has a significant antiproliferative effect on the PC3 tumor cell line, with an IC50 value close to that of dermaseptin-B2. Its antitumor activity has been confirmed in vivo in a xenograft mouse model with PC3 tumors and appears to be better tolerated than dermaseptin-B2. Biophysical experiments showed that the addition of LHRH to dermaseptin-B2 did not alter its secondary structure or biological activity. The combination of different experimental approaches indicated that this hormonotoxin induces cell death by an apoptotic mechanism instead of necrosis, as observed for dermaseptin-B2. These results could explain the lower toxicity observed for this hormonotoxin compared to dermaseptin-B2 and may represent a promising targeting approach for cancer therapy.
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Hörning M, Bullmann T, Shibata T. Local Membrane Curvature Pins and Guides Excitable Membrane Waves in Chemotactic and Macropinocytic Cells - Biomedical Insights From an Innovative Simple Model. Front Cell Dev Biol 2021; 9:670943. [PMID: 34604207 PMCID: PMC8479871 DOI: 10.3389/fcell.2021.670943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 08/16/2021] [Indexed: 11/13/2022] Open
Abstract
PIP3 dynamics observed in membranes are responsible for the protruding edge formation in cancer and amoeboid cells. The mechanisms that maintain those PIP3 domains in three-dimensional space remain elusive, due to limitations in observation and analysis techniques. Recently, a strong relation between the cell geometry, the spatial confinement of the membrane, and the excitable signal transduction system has been revealed by Hörning and Shibata (2019) using a novel 3D spatiotemporal analysis methodology that enables the study of membrane signaling on the entire membrane (Hörning and Shibata, 2019). Here, using 3D spatial fluctuation and phase map analysis on actin polymerization inhibited Dictyostelium cells, we reveal a spatial asymmetry of PIP3 signaling on the membrane that is mediated by the contact perimeter of the plasma membrane — the spatial boundary around the cell-substrate adhered area on the plasma membrane. We show that the contact perimeter guides PIP3 waves and acts as a pinning site of PIP3 phase singularities, that is, the center point of spiral waves. The contact perimeter serves as a diffusion influencing boundary that is regulated by a cell size- and shape-dependent curvature. Our findings suggest an underlying mechanism that explains how local curvature can favor actin polymerization when PIP3 domains get pinned at the curved protrusive membrane edges in amoeboid cells.
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Affiliation(s)
- Marcel Hörning
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany.,Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Torsten Bullmann
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Tatsuo Shibata
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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6
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Deshwal A, Maiti S. Macromolecular Crowding Effect on the Activity of Liposome-Bound Alkaline Phosphatase: A Paradoxical Inhibitory Action. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7273-7284. [PMID: 34086469 DOI: 10.1021/acs.langmuir.1c01177] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The cytoplasm of a cell is extremely crowded, with 20-30% being large biomolecules. This crowding enforces a significant amount of the physical and chemical barrier around biomolecules, so understanding any biomolecular event within the cellular system is challenging. Unsurprisingly, enzymes show a diverse kind of catalytic behavior inside a crowded environment and thus have remained an area of active interest in the last few decades. The situation can become even more complex and exciting in the case of understanding the behavior of a membrane-bound enzyme (almost 25-30% of enzymes are membrane-bound) in such a crowded environment that until now has remained unexplored. Herein, we have particularly investigated how a membrane-bound enzyme (using liposome-bound alkaline phosphatase) can behave in a crowded environment comprising polymer molecule-like poly(ethylene glycol) (PEG) of different weights (PEG400, PEG4000, and PEG9000) and Ficoll 400. We have compared the activity using a polymer microbead conjugated enzyme and have found that liposome-bound alkaline phosphatase had much higher activity in crowded environments, showing the importance and superiority of soft-deformable particles (i.e., vesicles) over hard spheres in macro-molecularly crowded media. Interstingly, we have found a paradoxical behavior of inhibitors in terms of both their extent and pathway of inhibitory action. For instance, phosphates, known as competitive inhibitors in buffer, behave as uncompetitive inhibitors in liposome-bound enzymes in crowded media with an ∼5-fold less inhibitory effect, whereas phenyl alanine (an uncompetitive inhibitor in buffer) did not show any inhibitory potential when the enzyme was membrane-bound and in crowded media containing PEG9000 (30 wt %). Overall, this demonstration elucidates aspects of membrane-bound enzymes in crowded media in terms of both catalytic behavior and inhibitory actions and can lead to further studies of the understanding of enzymatic behavior in such complex crowded environments having a dampening effect in regular diffusive transport.
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Affiliation(s)
- Akshi Deshwal
- Indian Institute of Science Education and Research (IISER) Mohali, Department of Chemical Sciences, Knowledge City, Manauli 140306, India
| | - Subhabrata Maiti
- Indian Institute of Science Education and Research (IISER) Mohali, Department of Chemical Sciences, Knowledge City, Manauli 140306, India
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7
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Highly synergistic antimicrobial activity of magainin 2 and PGLa peptides is rooted in the formation of supramolecular complexes with lipids. Sci Rep 2020; 10:11652. [PMID: 32669585 PMCID: PMC7363891 DOI: 10.1038/s41598-020-68416-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/22/2020] [Indexed: 11/21/2022] Open
Abstract
Magainin 2 and PGLa are cationic, amphipathic antimicrobial peptides which when added as equimolar mixture exhibit a pronounced synergism in both their antibacterial and pore-forming activities. Here we show for the first time that the peptides assemble into defined supramolecular structures along the membrane interface. The resulting mesophases are quantitatively described by state-of-the art fluorescence self-quenching and correlation spectroscopies. Notably, the synergistic behavior of magainin 2 and PGLa correlates with the formation of hetero-domains and an order-of-magnitude increased membrane affinity of both peptides. Enhanced membrane association of the peptide mixture is only observed in the presence of phophatidylethanolamines but not of phosphatidylcholines, lipids that dominate bacterial and eukaryotic membranes, respectively. Thereby the increased membrane-affinity of the peptide mixtures not only explains their synergistic antimicrobial activity, but at the same time provides a new concept to increase the therapeutic window of combinatorial drugs.
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8
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Membrane molecular crowding enhances MreB polymerization to shape synthetic cells from spheres to rods. Proc Natl Acad Sci U S A 2020; 117:1902-1909. [PMID: 31932440 DOI: 10.1073/pnas.1914656117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Executing gene circuits by cell-free transcription-translation into cell-sized compartments, such as liposomes, is one of the major bottom-up approaches to building minimal cells. The dynamic synthesis and proper self-assembly of macromolecular structures inside liposomes, the cytoskeleton in particular, stands as a central limitation to the development of cell analogs genetically programmed. In this work, we express the Escherichia coli gene mreB inside vesicles with bilayers made of lipid-polyethylene glycol (PEG). We demonstrate that two-dimensional molecular crowding, emulated by the PEG molecules at the lipid bilayer, is enough to promote the polymerization of the protein MreB at the inner membrane into a sturdy cytoskeleton capable of transforming spherical liposomes into elongated shapes, such as rod-like compartments. We quantitatively describe this mechanism with respect to the size of liposomes, lipid composition of the membrane, crowding at the membrane, and strength of MreB synthesis. So far unexplored, molecular crowding at the surface of synthetic cells emerges as an additional development with potential broad applications. The symmetry breaking observed could be an important step toward compartment self-reproduction.
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John T, Greene GW, Patil NA, Dealey TJA, Hossain MA, Abel B, Martin LL. Adsorption of Amyloidogenic Peptides to Functionalized Surfaces Is Biased by Charge and Hydrophilicity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14522-14531. [PMID: 31537064 DOI: 10.1021/acs.langmuir.9b02063] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Surfaces are abundant in living systems, such as in the form of cellular membranes, and govern many biological processes. In this study, the adsorption of the amyloidogenic model peptides GNNQQNY, NNFGAIL, and VQIVYK as well as the amyloid-forming antimicrobial peptide uperin 3.5 (U3.5) were studied at low concentrations (100 μM) to different surfaces. The technique of a quartz crystal microbalance with dissipation monitoring (QCM-D) was applied as it enables the monitoring of mass binding to sensors at nanogram sensitivity. Gold-coated quartz sensors were used as unmodified gold surfaces or functionalized with self-assembled monolayers (SAMs) of alkanethiols (terminated as methyl, amino, carboxyl, and hydroxyl) resulting in different adsorption affinities of the peptides. Our objective was to evaluate the underlying role of the nature and feature of interfaces in biological systems which could concentrate peptides and impact or trigger peptide aggregation processes. In overall, the largely hydrophobic peptides adsorbed with preference to hydrophobic or countercharged surfaces. Further, the glycoprotein lubricin (LUB) was tested as an antiadhesive coating. Despite its hydrophilicity, the adsorption of peptides to LUB coated sensors was similar to the adsorption to unmodified gold surfaces, which indicates that some peptides diffused through the LUB layer to reach the underlying gold sensor surface. The LUB protein-antiadhesive is thus more effective as a biomaterial coating against larger biomolecules than small peptides under the conditions used here. This study provides directions toward a better understanding of amyloid peptide adsorption to biologically relevant interfaces, such as cellular membranes.
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Affiliation(s)
- Torsten John
- School of Chemistry , Monash University , Clayton , Victoria 3800 , Australia
- Leibniz Institute of Surface Engineering (IOM) , Permoserstraße 15 , 04318 Leipzig , Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry , Leipzig University , Linnéstraße 3 , 04103 Leipzig , Germany
| | - George W Greene
- Institute for Frontier Materials , Deakin University , 75 Pigdons Road , Waurn Ponds , Victoria 3216 , Australia
| | - Nitin A Patil
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Tiara J A Dealey
- School of Chemistry , Monash University , Clayton , Victoria 3800 , Australia
| | - Mohammed A Hossain
- Florey Institute of Neuroscience and Mental Health , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM) , Permoserstraße 15 , 04318 Leipzig , Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry , Leipzig University , Linnéstraße 3 , 04103 Leipzig , Germany
| | - Lisandra L Martin
- School of Chemistry , Monash University , Clayton , Victoria 3800 , Australia
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10
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Abstract
Comprehensive data about the composition and structure of cellular components have enabled the construction of quantitative whole-cell models. While kinetic network-type models have been established, it is also becoming possible to build physical, molecular-level models of cellular environments. This review outlines challenges in constructing and simulating such models and discusses near- and long-term opportunities for developing physical whole-cell models that can connect molecular structure with biological function.
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Affiliation(s)
- Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA;
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Yuji Sugita
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
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Abstract
Amphipathic, pH-responsive, membrane-active peptides such as LAH4 and derivatives thereof have the ability to effectively deliver genes and small interfering RNA (siRNA) into mammalian cells. Their ability to bind and protect nucleic acids and then disrupt membranes when activated at low pH enables them to harness the endocytic machinery to deliver cargo efficiently and with low associated toxicity. This chapter describes protocols for the chemical synthesis of transfection peptides of the LAH4 family, complex formation with nucleic acids, and their use for the in vitro delivery of either plasmid DNA or siRNA into mammalian cell lines.
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Liu W, Fu L, Wang Z, Sohrabpour Z, Li X, Liu Y, Wang HF, Yan ECY. Two dimensional crowding effects on protein folding at interfaces observed by chiral vibrational sum frequency generation spectroscopy. Phys Chem Chem Phys 2018; 20:22421-22426. [PMID: 30159555 DOI: 10.1039/c7cp07061f] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
The crowding effect is prevalent in cellular environments due to high concentrations of biomacromolecules. It can alter the structures and dynamics of proteins and thus impact protein functions. The crowding effect is important not only in 3-dimensional cytoplasm but also for a 2-dimensional (2D) cell surface due to the presence of membrane proteins and glycosylation of membrane proteins and phospholipids. These proteins and phospholipids - with limited translational degrees of freedom along the surface normal - are confined in 2D space. Although the crowding effect at interfaces has been studied by adding crowding agents to bulk solution, the 2D crowding effect remains largely unexplored. This is mostly due to challenges in controlling 2D crowding and synergistic use of physical methods for in situ protein characterization. To address these challenges, we applied chiral vibrational sum frequency generation (SFG) spectroscopy to probe the sp1 zinc finger (ZnF), a 31-amino acid protein, folding into a β-hairpin/α-helix (ββα) motif upon binding to Zn2+. We anchored ZnF at the air/water interface via covalent linkage of ZnF to palmitic acid and controlled 2D crowding by introducing neutral lipid as a spacer. We obtained chiral amide I SFG spectra upon addition of Zn2+ and/or spacer lipid. The chiral SFG spectra show that interfacial crowding in the absence of spacer lipid hinders ZnF from folding into the ββα structure even in the presence of Zn2+. The results establish a paradigm for future quantitative, systematic studies of interfacial crowding effects.
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Affiliation(s)
- Wei Liu
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520, USA.
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13
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Dermaseptins as potential antirabies compounds. Vaccine 2018; 37:4694-4700. [PMID: 29439871 DOI: 10.1016/j.vaccine.2018.01.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 01/16/2018] [Accepted: 01/22/2018] [Indexed: 01/11/2023]
Abstract
Over the last 20 years, natural peptides playing a key role in defense mechanisms and innate immunity have been isolated from unicellular organisms. Amphibian skin secretes dermaseptins, 24-34 amino acids in length that have a wide antimicrobial spectrum incorporating yeast, fungi, protozoa, bacteria and enveloped viruses. The anti-rabies virus (RABV) activity of dermaseptins S3 (30aa) and S4 (28aa) from Phyllomedusa sauvagei has been investigated, and further dissected its molecular basis by comparing punctual mutation or deletion of S4 analogues. The results showed that: (1) S4 is more active than S3 against RABV infection, 89% versus 38% inhibition at 7.5 μM; (2) the 5 NH2-aa of S4 are crucial for its inhibitory potential (S46-28 lost any inhibition) but the COOH terminus stabilizes the inhibitory potential (S41-16 showed only 23% inhibition at 7.5 μM); (3) there is a correlation between viral inhibition and dermaseptin cytotoxicity, which remains however moderated for BSR cells (≤12% at 10 μM). A single mutation in position 4 (S4M4K) slightly reduced cytotoxicity while keeping its antiviral activity, 97% at 7.5 μM. S4 and S4M4K showed an antiviral activity in vitro when provided 1 h after infection. In vivo experiments in mice by intramuscular injection of non-toxic doses of dermaseptin S4M4K 1 h post-infection by a lethal dose of RABV at the same site allowed more than 50% improvement in mice survival. This study highlights the potential interest of dermaseptins as non-expansive alternatives to rabies immunoglobulins for the treatment of rabies that continues to claim about 60,000 human lives per year worldwide, almost exclusively in developing countries.
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14
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Tang W, Pu C, Li M. Interaction between Antibacterial Peptide Apep10 and Escherichia coli Membrane Lipids Evaluated Using Liposome as Pseudo-Stationary Phase. PLoS One 2017; 12:e0164594. [PMID: 28052090 PMCID: PMC5215004 DOI: 10.1371/journal.pone.0164594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/27/2016] [Indexed: 11/18/2022] Open
Abstract
Liposomes constructed from Escherichia coli membrane lipids were used as a pseudo-stationary phase in capillary electrophoresis and immobilised liposome chromatography to evaluate the interaction between antibacterial peptide (ABP) Apep10 and bacterial membrane lipids. The peptide mobility decreased as the concentration of liposomes increased, providing evidence for the existence of this interaction. The binding constant between Apep10 and the Escherichia coli membranes lipid liposome was higher than that of Apep10 with a mixed phospholipids liposome at the same temperature. The capillary electrophoresis results indicate that the binding ability of Apep10 with a liposome was dependent on the liposome’s lipid compositions. Thermodynamic analysis by immobilised liposome chromatography indicated that hydrophobic and electrostatic effects contributed to the partitioning of Apep10 in the membrane lipids. The liposomes constructed from bacterial membrane lipid were more suitable as the model membranes used to study dynamic ABP/membrane interactions than those constructed from specific ratios of particular phospholipids, with its more biomimetic phospholipid composition and contents. This study provides an appropriate model for the evaluation of ABP-membrane interactions.
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Affiliation(s)
- Wenting Tang
- School of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China
- * E-mail:
| | - Chuanfen Pu
- School of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China
| | - Man Li
- School of Food Science and Engineering, Qingdao Agricultural University, Qingdao, 266109, China
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15
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Intramembrane congestion effects on lysenin channel voltage-induced gating. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 45:187-94. [PMID: 26695013 DOI: 10.1007/s00249-015-1104-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/29/2015] [Accepted: 11/24/2015] [Indexed: 10/22/2022]
Abstract
All cell membranes are packed with proteins. The ability to investigate the regulatory mechanisms of protein channels in experimental conditions mimicking their congested native environment is crucial for understanding the environmental physicochemical cues that may fundamentally contribute to their functionality in natural membranes. Here we report on investigations of the voltage-induced gating of lysenin channels in congested conditions experimentally achieved by increasing the number of channels inserted into planar lipid membranes. Typical electrophysiology measurements reveal congestion-induced changes to the voltage-induced gating, manifested as a significant reduction of the response to external voltage stimuli. Furthermore, we demonstrate a similar diminished voltage sensitivity for smaller populations of channels by reducing the amount of sphingomyelin in the membrane. Given lysenin's preference for targeting lipid rafts, this result indicates the potential role of the heterogeneous organization of the membrane in modulating channel functionality. Our work indicates that local congestion within membranes may alter the energy landscape and the kinetics of conformational changes of lysenin channels in response to voltage stimuli. This level of understanding may be extended to better characterize the role of the specific membrane environment in modulating the biological functionality of protein channels in health and disease.
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Fernandes F, Coutinho A, Prieto M, Loura LMS. Electrostatically driven lipid-protein interaction: Answers from FRET. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1837-48. [PMID: 25769805 DOI: 10.1016/j.bbamem.2015.02.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 02/23/2015] [Indexed: 12/13/2022]
Abstract
Electrostatics govern the association of a large number of proteins with cellular membranes. In some cases, these proteins present specialized lipid-binding modules or membrane targeting domains while in other cases association is achieved through nonspecific interaction of unstructured clusters of basic residues with negatively charged lipids. Given its spatial resolution in the nanometer range, Förster resonance energy transfer (FRET) is a powerful tool to give insight into protein-lipid interactions and provide molecular level information which is difficult to retrieve with other spectroscopic techniques. In this review we present and discuss the basic formalisms of both hetero- and homo-FRET pertinent to the most commonly encountered problems in lipid-protein interaction studies and highlight some examples of implementations of different FRET methodologies to characterize lipid/protein systems in which electrostatic interactions play a crucial role. This article is part of a Special Issue entitled: Lipid-protein interactions.
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Affiliation(s)
- Fábio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Ana Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; Dep. Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Luís M S Loura
- Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal; Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal.
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pH modulates the activity and synergism of the airway surface liquid antimicrobials β-defensin-3 and LL-37. Proc Natl Acad Sci U S A 2014; 111:18703-8. [PMID: 25512526 DOI: 10.1073/pnas.1422091112] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The pulmonary airways are continuously exposed to bacteria. As a first line of defense against infection, the airway surface liquid (ASL) contains a complex mixture of antimicrobial factors that kill inhaled and aspirated bacteria. The composition of ASL is critical for antimicrobial effectiveness. For example, in cystic fibrosis an abnormally acidic ASL inhibits antimicrobial activity. Here, we tested the effect of pH on the activity of an ASL defensin, human β-defensin-3 (hBD-3), and the cathelicidin-related peptide, LL-37. We found that reducing pH from 8.0 to 6.8 reduced the ability of both peptides to kill Staphylococcus aureus. An acidic pH also attenuated LL-37 killing of Pseudomonas aeruginosa. In addition, we discovered synergism between hBD-3 and LL-37 in killing S. aureus. LL-37 and lysozyme were also synergistic. Importantly, an acidic pH reduced the synergistic effects of combinations of ASL antibacterials. These results indicate that an acidic pH reduces the activity of individual ASL antimicrobials, impairs synergism between them, and thus may disrupt an important airway host defense mechanism.
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Aisenbrey C, Bechinger B. Molecular packing of amphipathic peptides on the surface of lipid membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:10374-10383. [PMID: 25105913 DOI: 10.1021/la500998g] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
When polypeptides bind to the membrane surface, they become confined to a restricted quasi-two-dimensional space where peptide-peptide interactions become highly relevant, and the concept of a crowded medium is appropriate. Within this crowded environment interesting effects like clustering, separation of phases, cooperative alignment, and common movements occur. Here we investigated such effects by measuring distances between fluorophore-labeled peptides in the range ≤1 nm by fluorescence self-quenching. For helical peptides with dimensions of approximately 1 × 3 nm such a small "ruler" is sensitive to the packing of the labeled peptides and thereby to their molecular arrangement. A novel approach to characterize peptide-peptide interactions within membranes is presented using the designer peptide LAH4. This sequence changes membrane topology in a controlled manner being transmembrane at neutral conditions but oriented parallel to the surface at low pH. Experimental measurements of the fluorescence self-quenching of close-by chromophores and the changes that occur upon dilution with unlabeled peptides are used to analyze the peptide distribution within the membrane surface. The data show a strong effect of electrostatic interactions and under some experimental conditions clustering of the peptides. Furthermore, the results suggest that at pH 4 the peptides arrange along the membrane surface in an ordered mesophase-like arrangement.
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Affiliation(s)
- Christopher Aisenbrey
- Institut de Chimie, UMR7177, Université de Strasbourg/CNRS , 1, rue Blaise Pascal, 67000 Strasbourg, France
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Kemayo Koumkoua P, Aisenbrey C, Salnikov E, Rifi O, Bechinger B. On the design of supramolecular assemblies made of peptides and lipid bilayers. J Pept Sci 2014; 20:526-36. [PMID: 24909405 DOI: 10.1002/psc.2656] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/29/2014] [Accepted: 04/29/2014] [Indexed: 02/02/2023]
Abstract
Peptides confer interesting properties to materials, supramolecular assemblies and to lipid membranes and are used in analytical devices or within delivery vehicles. Their relative ease of production combined with a high degree of versatility make them attractive candidates to design new such products. Here, we review and demonstrate how CD- and solid-state NMR spectroscopic approaches can be used to follow the reconstitution of peptides into membranes and to describe some of their fundamental characteristics. Whereas CD spectroscopy is used to monitor secondary structure in different solvent systems and thereby aggregation properties of the highly hydrophobic domain of p24, a protein involved in vesicle trafficking, solid-state NMR spectroscopy was used to deduce structural information and the membrane topology of a variety of peptide sequences found in nature or designed. (15)N chemical shift solid-state NMR spectroscopy indicates that the hydrophobic domain of p24 as well as a designed sequence of 19 hydrophobic amino acid residues adopt transmembrane alignments in phosphatidylcholine membranes. In contrast, the amphipathic antimicrobial peptide magainin 2 and the designed sequence LK15 align parallel to the bilayer surface. Additional angular information is obtained from deuterium solid-state NMR spectra of peptide sites labelled with (2)H3-alanine, whereas (31)P and (2)H solid-state NMR spectra of the lipids furnish valuable information on the macroscopic order and phase properties of the lipid matrix. Using these approaches, peptides and reconstitution protocols can be elaborated in a rational manner, and the analysis of a great number of peptide sequences is reviewed. Finally, a number of polypeptides with membrane topologies that are sensitive to a variety of environmental conditions such as pH, lipid composition and peptide-to-lipid ratio will be presented.
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Affiliation(s)
- Patricia Kemayo Koumkoua
- Université de Strasbourg / CNRS, UMR7177, Institut de Chimie, 1, rue Blaise Pascal, 67070, Strasbourg, France
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Investigation of membrane penetration depth and interactions of the amino-terminal domain of huntingtin: refined analysis by tryptophan fluorescence measurement. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2014; 43:347-60. [PMID: 24895024 DOI: 10.1007/s00249-014-0966-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/08/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
Abstract
The membrane-association properties of the amino-terminal domain of huntingtin are accompanied by subcellular redistribution of the protein in cellular compartments. In this study we used tryptophan substitution of amino-acid residues at different positions of the huntingtin 1-17 domain (Htt17) to precisely determine, for the first time, the depth of penetration of the peptides within the lipid bilayer. Initially, secondary structure preferences and membrane association properties were quantitatively determined for several membrane lipid compositions; they were found to be closely related to those of the natural peptide, indicating that changes in the sequence had little effect on these characteristics of the domain. The tryptophan-substituted peptides became inserted into the membranes' interfacial region, with average tryptophan positions between 7.5 and 11 Å from the bilayer center, in agreement with in-plane orientation of the peptide. Participation of the very-amino terminus of the peptide in the membrane-association process was demonstrated. The results not only revealed the occurrence of association intermediates when the huntingtin 1-17 anchoring sequence became inserted into the membrane but also suggest the formation of aggregates and/or oligomers during membrane association. When inserted, the F11W site was of crucial importance in lipid anchoring and stabilization of the whole peptide, whereas the terminal residues are located close to the membrane surface. The carboxy-terminal tryptophan (F17W), which also constitutes the site of the polyglutamine extension in the natural domain, was found closest to the aqueous environment, accompanied with the highest aqueous quenching constants. These results were used to propose a refined model of lipid interactions of the huntingtin 1-17 domain.
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Antimisiaris S, Mourtas S, Markoutsa E, Skouras A, Papadia K. Nanoparticles for Diagnosis and/or Treatment of Alzheimer's Disease. Adv Healthc Mater 2014. [DOI: 10.1002/9781118774205.ch4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Milano G, Kawakatsu T, De Nicola A. A hybrid particle–field molecular dynamics approach: a route toward efficient coarse-grained models for biomembranes. Phys Biol 2013; 10:045007. [DOI: 10.1088/1478-3975/10/4/045007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Antimicrobial peptide isolated from ovalbumin hydrolysate by immobilized liposome-binding extraction. Eur Food Res Technol 2013. [DOI: 10.1007/s00217-013-2034-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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24
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Kichler A, Mason AJ, Marquette A, Bechinger B. Histidine-rich cationic amphipathic peptides for plasmid DNA and siRNA delivery. Methods Mol Biol 2013; 948:85-103. [PMID: 23070765 DOI: 10.1007/978-1-62703-140-0_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Amphipathic, pH-responsive, membrane-active peptides such as LAH4 and derivatives thereof have the ability to effectively deliver genes and small interfering RNA (siRNA) into mammalian cells. Their ability to bind and protect nucleic acids and then disrupt membranes when activated at low pH enables them to harness the endocytic machinery to deliver cargo efficiently and with low associated toxicity. This chapter describes protocols for the chemical synthesis of transfection peptides of the LAH4 family, complex formation with nucleic acids, and their use for the in vitro delivery of either plasmid DNA or siRNA into mammalian cell lines.
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Affiliation(s)
- Antoine Kichler
- Laboratoire de Pharmacologie Chimique et Génétique et d'Imagerie, U1022 INSERM, Paris, France.
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25
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Lindén M, Sens P, Phillips R. Entropic tension in crowded membranes. PLoS Comput Biol 2012; 8:e1002431. [PMID: 22438801 PMCID: PMC3305330 DOI: 10.1371/journal.pcbi.1002431] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 02/01/2012] [Indexed: 11/18/2022] Open
Abstract
Unlike their model membrane counterparts, biological membranes are richly decorated with a heterogeneous assembly of membrane proteins. These proteins are so tightly packed that their excluded area interactions can alter the free energy landscape controlling the conformational transitions suffered by such proteins. For membrane channels, this effect can alter the critical membrane tension at which they undergo a transition from a closed to an open state, and therefore influence protein function in vivo. Despite their obvious importance, crowding phenomena in membranes are much less well studied than in the cytoplasm. Using statistical mechanics results for hard disk liquids, we show that crowding induces an entropic tension in the membrane, which influences transitions that alter the projected area and circumference of a membrane protein. As a specific case study in this effect, we consider the impact of crowding on the gating properties of bacterial mechanosensitive membrane channels, which are thought to confer osmoprotection when these cells are subjected to osmotic shock. We find that crowding can alter the gating energies by more than in physiological conditions, a substantial fraction of the total gating energies in some cases. Given the ubiquity of membrane crowding, the nonspecific nature of excluded volume interactions, and the fact that the function of many membrane proteins involve significant conformational changes, this specific case study highlights a general aspect in the function of membrane proteins. Biological membranes are a complex array of lipids and proteins. The typical bacterial membrane is made up of hundreds of copies of different species of membrane proteins embedded in a sea of different types of lipids. One of the distinguishing features of biological matter is the high degree of “crowding” to which the different macromolecules are subjected. In this work, we explore the consequences of such crowding in the membrane setting, building upon earlier work which has primarily focused on how crowding affects properties in the cytoplasm. The particular case study considered here centers on a class of membrane channels which respond to tension in the cell membrane serving to provide osmoprotection to cells subjected to osmotic shock. We explore how the critical tension at which these channels open depends upon the concentration of other membrane proteins, and conclude that it can be significantly higher at physiological protein densities compared to the intrinsic value measured in protein free membranes.
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Affiliation(s)
- Martin Lindén
- Department of Applied Physics, California Institute of Technology, Pasadena, California, United States of America
| | - Pierre Sens
- Laboratoire de Physico-Chimie Théorique, CNRS/UMR 7083, ESPCI, Paris, France
| | - Rob Phillips
- Department of Applied Physics, California Institute of Technology, Pasadena, California, United States of America
- Laboratoire de Physico-Chimie Théorique, CNRS/UMR 7083, ESPCI, Paris, France
- Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- * E-mail:
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Taylor M, Moore S, Mourtas S, Niarakis A, Re F, Zona C, Ferla BL, Nicotra F, Masserini M, Antimisiaris SG, Gregori M, Allsop D. Effect of curcumin-associated and lipid ligand-functionalized nanoliposomes on aggregation of the Alzheimer's Aβ peptide. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2011; 7:541-50. [DOI: 10.1016/j.nano.2011.06.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 06/13/2011] [Accepted: 06/18/2011] [Indexed: 01/09/2023]
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27
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Melo AM, Prieto M, Coutinho A. The effect of variable liposome brightness on quantifying lipid–protein interactions using fluorescence correlation spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2559-68. [DOI: 10.1016/j.bbamem.2011.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 06/01/2011] [Accepted: 06/01/2011] [Indexed: 11/17/2022]
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28
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Gross LCM, Castell OK, Wallace MI. Dynamic and reversible control of 2D membrane protein concentration in a droplet interface bilayer. NANO LETTERS 2011; 11:3324-3328. [PMID: 21726072 DOI: 10.1021/nl201689v] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We form an artificial lipid bilayer between a nanolitre aqueous droplet and a supporting hydrogel immersed in an oil/lipid solution. Manipulation of the axial position of the droplet relative to the hydrogel controls the size of the bilayer formed at the interface; this enables the surface density of integral membrane proteins to be controlled. We are able to modulate the surface density of the β-barrel pore-forming toxin α-hemolysin over a range of 4 orders of magnitude within a time frame of a few seconds. The concentration changes are fully reversible. Membrane protein function and diffusion are unaltered, as measured by single molecule microscopy and single channel electrical recording.
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Affiliation(s)
- Linda C M Gross
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA, Oxford, U.K
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29
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Fu R, Wang X, Li C, Santiago-Miranda AN, Pielak GJ, Tian F. In situ structural characterization of a recombinant protein in native Escherichia coli membranes with solid-state magic-angle-spinning NMR. J Am Chem Soc 2011; 133:12370-3. [PMID: 21774553 DOI: 10.1021/ja204062v] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The feasibility of using solid-state magic-angle-spinning NMR spectroscopy for in situ structural characterization of the LR11 (sorLA) transmembrane domain (TM) in native Escherichia coli membranes is presented. LR11 interacts with the human amyloid precursor protein (APP), a central player in the pathology of Alzheimer's disease. The background signals from E. coli lipids and membrane proteins had only minor effects on the LR11 TM resonances. Approximately 50% of the LR11 TM residues were assigned by using (13)C PARIS data. These assignments allowed comparisons of the secondary structure of the LR11 TM in native membrane environments and commonly used membrane mimics (e.g., micelles). In situ spectroscopy bypasses several obstacles in the preparation of membrane proteins for structural analysis and offers the opportunity to investigate how membrane heterogeneity, bilayer asymmetry, chemical gradients, and macromolecular crowding affect the protein structure.
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Affiliation(s)
- Riqiang Fu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
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30
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Georgescu J, Munhoz VHO, Bechinger B. NMR structures of the histidine-rich peptide LAH4 in micellar environments: membrane insertion, pH-dependent mode of antimicrobial action, and DNA transfection. Biophys J 2011; 99:2507-15. [PMID: 20959091 DOI: 10.1016/j.bpj.2010.05.038] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 05/12/2010] [Accepted: 05/21/2010] [Indexed: 11/26/2022] Open
Abstract
The LAH4 family of histidine-rich peptides exhibits potent antimicrobial and DNA transfection activities, both of which require interactions with cellular membranes. The bilayer association of the peptides has been shown to be strongly pH-dependent, with in-planar alignments under acidic conditions and transmembrane orientations when the histidines are discharged. Therefore, we investigated the pH- and temperature-dependent conformations of LAH4 in DPC micellar solutions and in a TFE/PBS solvent mixture. In the presence of detergent and at pH 4.1, LAH4 adopts helical conformations between residues 9 and 24 concomitantly with a high hydrophobic moment. At pH 6.1, a helix-loop-helix structure forms with a hinge encompassing residues His¹⁰-Ala¹³. The data suggest that the high density of histidine residues and the resulting electrostatic repulsion lead to both a decrease in the pK values of the histidines and a less stable α-helical conformation of this region. The hinged structure at pH 6.1 facilitates membrane anchoring and insertion. At pH 7.8, the histidines are uncharged and an extended helical conformation including residues 4-21 is again obtained. LAH4 thus exhibits a high degree of conformational plasticity. The structures provide a stroboscopic view of the conformational changes that occur during membrane insertion, and are discussed in the context of antimicrobial activity and DNA transfection.
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Affiliation(s)
- Julia Georgescu
- Institut de Chimie, Université de Strasbourg/Centre National de Recherche Scientifique, France
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31
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Gorbenko G, Trusova V. Protein aggregation in a membrane environment. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2011; 84:113-42. [DOI: 10.1016/b978-0-12-386483-3.00002-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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32
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Designed fluorescent probes reveal interactions between amyloid-beta(1-40) peptides and GM1 gangliosides in micelles and lipid vesicles. Biophys J 2010; 99:1510-9. [PMID: 20816063 DOI: 10.1016/j.bpj.2010.06.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 06/16/2010] [Accepted: 06/17/2010] [Indexed: 12/20/2022] Open
Abstract
A hallmark of the common Alzheimer's disease (AD) is the pathological conversion of its amphiphatic amyloid-beta (Abeta) peptide into neurotoxic aggregates. In AD patients, these aggregates are often found to be tightly associated with neuronal G(M1) ganglioside lipids, suggesting an involvement of G(M1) not only in aggregate formation but also in neurotoxic events. Significant interactions were found between micelles made of newly synthesized fluorescent G(M1) gangliosides labeled in the polar headgroup or the hydrophobic chain and Abeta(1-40) peptide labeled with a BODIPY-FL-C1 fluorophore at positions 12 and 26, respectively. From an analysis of energy transfer between the different fluorescence labels and their location in the molecules, we were able to place the Abeta peptide inside G(M1) micelles, close to the hydrophobic-hydrophilic interface. Large unilamellar vesicles composed of a raftlike G(M1)/bSM/cholesterol lipid composition doped with labeled G(M1) at various positions also interact with labeled Abeta peptide tagged to amino acids 2 or 26. A faster energy transfer was observed from the Abeta peptide to bilayers doped with 581/591-BODIPY-C(11)-G(M1) in the nonpolar part of the lipid compared with 581/591-BODIPY-C(5)-G(M1) residing in the polar headgroup. These data are compatible with a clustering process of G(M1) molecules, an effect that not only increases the Abeta peptide affinity, but also causes a pronounced Abeta peptide penetration deeper into the lipid membrane; all these factors are potentially involved in Abeta peptide aggregate formation due to an altered ganglioside metabolism found in AD patients.
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Marquette A, Lorber B, Bechinger B. Reversible liposome association induced by LAH4: a peptide with potent antimicrobial and nucleic acid transfection activities. Biophys J 2010; 98:2544-53. [PMID: 20513398 DOI: 10.1016/j.bpj.2010.02.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 01/28/2010] [Accepted: 02/12/2010] [Indexed: 11/16/2022] Open
Abstract
We report on the reversible association of anionic liposomes induced by an antimicrobial peptide (LAH4). The process has been characterized for mixed membranes of POPC and POPS at molar ratios of 1:1, 3:1, and 9:1. Although the vesicles remain in suspension in the presence of excess amounts of peptide, the addition of more lipids results in surface charge neutralization, aggregation of the liposomes, and formation of micrometer-sized structures that coexist in equilibrium with vesicles in suspension. At low ratios of anionic lipids, vesicle aggregation is a reversible process, and vesicle disassembly is observed upon inversion of the surface charge by further supplementation with anionic vesicles. In contrast, a different process, membrane fusion, occurs in the presence of high phosphatidylserine concentrations. Upon binding to membranes containing low POPS concentrations, the peptide adopts an in-plane alpha-helical structure, a secondary structure that is conserved during vesicle association and dissociation. Our finding that peptides are essential for vesicle aggregation contributes to a better understanding of the activity of antimicrobial peptides, and suggests an additional layer of complexity in membrane-protein lipid interactions.
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Affiliation(s)
- Arnaud Marquette
- Résonance Magnétique Nucléaire et Biophysique des Membranes, Institut de Chimie, Unite Mixte de Recherche 7177, France
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34
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Paasch S, Brunner E. Trends in solid-state NMR spectroscopy and their relevance for bioanalytics. Anal Bioanal Chem 2010; 398:2351-62. [DOI: 10.1007/s00216-010-4037-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/14/2010] [Accepted: 07/14/2010] [Indexed: 01/25/2023]
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35
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Elcock AH. Models of macromolecular crowding effects and the need for quantitative comparisons with experiment. Curr Opin Struct Biol 2010; 20:196-206. [PMID: 20167475 DOI: 10.1016/j.sbi.2010.01.008] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 01/17/2010] [Accepted: 01/21/2010] [Indexed: 01/19/2023]
Abstract
In recent years significant effort has been devoted to exploring the potential effects of macromolecular crowding on protein folding and association phenomena. Theoretical calculations and molecular simulations have, in particular, been exploited to describe aspects of protein behavior in crowded and confined conditions and many aspects of the simulated behavior have reflected, at least at a qualitative level, the behavior observed in experiments. One major and immediate challenge for the theorists is to now produce models capable of making quantitatively accurate predictions of in vitro behavior. A second challenge is to derive models that explain results obtained from experiments performed in vivo, the results of which appear to call into question the assumed dominance of excluded-volume effects in vivo.
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Affiliation(s)
- Adrian H Elcock
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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Bordag N, Keller S. α-Helical transmembrane peptides: A “Divide and Conquer” approach to membrane proteins. Chem Phys Lipids 2010; 163:1-26. [PMID: 19682979 DOI: 10.1016/j.chemphyslip.2009.07.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 11/26/2022]
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37
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Transmembrane vs. non-transmembrane hydrophobic helix topography in model and natural membranes. Curr Opin Struct Biol 2009; 19:464-72. [DOI: 10.1016/j.sbi.2009.07.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 07/10/2009] [Indexed: 11/21/2022]
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38
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Abstract
In cell membranes, membrane proteins occupy approximately 30% of the total surface area. Crowding effects similar to those in the solution phase are thus to be expected. In addition, there are crowding effects unique to proteins bound to the two-dimensional membranes, such as those exerted on the equilibration of a protein between two membrane orientations and on the redistribution of proteins between different locations in a cell membrane. This article aims to present a theoretical framework for understanding the various crowding effects within membranes. For illustration, the theory is used to analyze previously published experimental and simulation data. It is hoped that the article will encourage quantitative analyses in future experiments and spur systematic investigation of membrane crowding effects.
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Affiliation(s)
- Huan-Xiang Zhou
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, USA.
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39
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Binding-site geometry and flexibility in DC-SIGN demonstrated with surface force measurements. Proc Natl Acad Sci U S A 2009; 106:11524-9. [PMID: 19553201 DOI: 10.1073/pnas.0901783106] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The dendritic cell receptor DC-SIGN mediates pathogen recognition by binding to glycans characteristic of pathogen surfaces, including those found on HIV. Clustering of carbohydrate-binding sites in the receptor tetramer is believed to be critical for targeting of pathogen glycans, but the arrangement of these sites remains poorly understood. Surface force measurements between apposed lipid bilayers displaying the extracellular domain of DC-SIGN and a neoglycolipid bearing an oligosaccharide ligand provide evidence that the receptor is in an extended conformation and that glycan docking is associated with a conformational change that repositions the carbohydrate-recognition domains during ligand binding. The results further show that the lateral mobility of membrane-bound ligands enhances the engagement of multiple carbohydrate-recognition domains in the receptor oligomer with appropriately spaced ligands. These studies highlight differences between pathogen targeting by DC-SIGN and receptors in which binding sites at fixed spacing bind to simple molecular patterns.
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40
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Galanth C, Abbassi F, Lequin O, Ayala-Sanmartin J, Ladram A, Nicolas P, Amiche M. Mechanism of antibacterial action of dermaseptin B2: interplay between helix-hinge-helix structure and membrane curvature strain. Biochemistry 2009; 48:313-27. [PMID: 19113844 DOI: 10.1021/bi802025a] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dermaseptin B2 (Drs B2) is a 33-residue-long cationic, alpha-helical antimicrobial peptide endowed with membrane-damaging activity against a broad spectrum of microorganisms, including bacteria, yeasts, fungi, and protozoa, but its precise mechanism of action remained ill-defined. A detailed characterization of peptide-membrane interactions of Drs B2 was undertaken in comparison with a C-terminal truncated analogue, [1-23]-Drs B2, that was virtually inactive on bacteria despite retaining the cationic charge of the full-length peptide. Both peptides were tested on living cells using membrane permeabilization assays and on large unilamellar and multilamellar phospholipid vesicles composed of binary lipid mixtures by dye leakage assay, fluorescence spectroscopy, circular dichroism, and differential scanning calorimetry and also on SDS micelles using NMR spectroscopy. The results indicate that Drs B2 induces a strong perturbation of anionic lipid bilayers, resides at the hydrocarbon core-water interface, parallel to the plane of the membrane, and interacts preferentially with the polar head groups and glycerol backbone region of the anionic phospholipids, as well as the region of the lipid acyl chain near the bilayer surface. The interfacial location of Drs B2 induces a positive curvature of the bilayer and clustering of anionic lipids, consistent with a carpet mechanism, that may lead to the formation of mixed peptide-phospholipid toroidal, transient pores and membrane permeation/disruption once a threshold peptide accumulation is reached. In constrast, the truncated [1-23]-Drs B2 analogue interacts at the head group level without penetrating and perturbing the hydrophobic core of the bilayer. NMR study in SDS micelles showed that [1-23]-Drs B2 adopts a well-defined helix encompassing residues 2-20, whereas Drs B2 was previously found to adopt helical structures interrupted around the Val(9)-Gly(10) segment. Thus the antibacterial activity of Drs B2 depends markedly on a threshold number of hydrophobic residues to be present on both extremities of the helix. In a membrane environment with a strong positive curvature strain, Drs B2 can adopt a flexible helix-hinge-helix structure that facilitates the concomitant insertion of the strongly hydrophobic N- and C-termini of the peptide into the acyl core of the membrane.
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Affiliation(s)
- Cécile Galanth
- Peptidome de la Peau des Amphibiens, UPMC Universite Paris 06, CNRS FRE 2852, F-75005 Paris, France.
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41
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Tang YL, Shi YH, Zhao W, Hao G, Le GW. Discovery of a novel antimicrobial peptide using membrane binding-based approach. Food Control 2009. [DOI: 10.1016/j.foodcont.2008.03.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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42
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Insertion mode of a novel anionic antimicrobial peptide MDpep5 (Val-Glu-Ser-Trp-Val) from Chinese traditional edible larvae of housefly and its effect on surface potential of bacterial membrane. J Pharm Biomed Anal 2008; 48:1187-94. [DOI: 10.1016/j.jpba.2008.09.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 09/01/2008] [Indexed: 11/18/2022]
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43
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Byström R, Aisenbrey C, Borowik T, Bokvist M, Lindström F, Sani MA, Olofsson A, Gröbner G. Disordered proteins: biological membranes as two-dimensional aggregation matrices. Cell Biochem Biophys 2008; 52:175-89. [PMID: 18975139 DOI: 10.1007/s12013-008-9033-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2008] [Indexed: 01/05/2023]
Abstract
Aberrant folded proteins and peptides are hallmarks of amyloidogenic diseases. However, the molecular processes that cause these proteins to adopt non-native structures in vivo and become cytotoxic are still largely unknown, despite intense efforts to establish a general molecular description of their behavior. Clearly, the fate of these proteins is ultimately linked to their immediate biochemical environment in vivo. In this review, we focus on the role of biological membranes, reactive interfaces that not only affect the conformational stability of amyloidogenic proteins, but also their aggregation rates and, probably, their toxicity. We first provide an overview of recent work, starting with findings regarding the amphiphatic amyloid-beta protein (Abeta), which give evidence that membranes can directly promote aggregation, and that the effectiveness in this process can be related to the presence of specific neuronal ganglioside lipids. In addition, we discuss the implications of recent research (medin as an detailed example) regarding putative roles of membranes in the misfolding behavior of soluble, non-amphiphatic proteins, which are attracting increasing interest. The potential role of membranes in exerting the toxic action of misfolded proteins will also be highlighted in a molecular context. In this review, we discuss novel NMR-based approaches for exploring membrane-protein interactions, and findings obtained using them, which we use to develop a molecular concept to describe membrane-mediated protein misfolding as a quasi-two-dimensional process rather than a three-dimensional event in a biochemical environment. The aim of the review is to provide researchers with a general understanding of the involvement of membranes in folding/misfolding processes in vivo, which might be quite universal and important for future research concerning amyloidogenic and misfolding proteins, and possible ways to prevent their toxic actions.
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Affiliation(s)
- Roberth Byström
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden
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44
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Zhou HX, Rivas G, Minton AP. Macromolecular crowding and confinement: biochemical, biophysical, and potential physiological consequences. Annu Rev Biophys 2008; 37:375-97. [PMID: 18573087 DOI: 10.1146/annurev.biophys.37.032807.125817] [Citation(s) in RCA: 1545] [Impact Index Per Article: 96.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Expected and observed effects of volume exclusion on the free energy of rigid and flexible macromolecules in crowded and confined systems, and consequent effects of crowding and confinement on macromolecular reaction rates and equilibria are summarized. Findings from relevant theoretical/simulation and experimental literature published from 2004 onward are reviewed. Additional complexity arising from the heterogeneity of local environments in biological media, and the presence of nonspecific interactions between macromolecules over and above steric repulsion, are discussed. Theoretical and experimental approaches to the characterization of crowding- and confinement-induced effects in systems approaching the complexity of living organisms are suggested.
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Affiliation(s)
- Huan-Xiang Zhou
- Department of Physics and Institute of Molecular Biophysics and School of Computational Science, Florida State University, Tallahassee, Florida 32306, USA.
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45
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Ramamoorthy A, Lee DK, Santos JS, Henzler-Wildman KA. Nitrogen-14 Solid-State NMR Spectroscopy of Aligned Phospholipid Bilayers to Probe Peptide−Lipid Interaction and Oligomerization of Membrane Associated Peptides. J Am Chem Soc 2008; 130:11023-9. [DOI: 10.1021/ja802210u] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Dong-Kuk Lee
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Jose S. Santos
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055
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