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Characterization and Differential Cytotoxicity of Gramicidin Nanoparticles Combined with Cationic Polymer or Lipid Bilayer. Pharmaceutics 2022; 14:pharmaceutics14102053. [PMID: 36297488 PMCID: PMC9610547 DOI: 10.3390/pharmaceutics14102053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/21/2022] Open
Abstract
Gramicidin (Gr) nanoparticles (NPs) and poly (diallyl dimethyl ammonium) chloride (PDDA) water dispersions were characterized and evaluated against Gram-positive and Gram-negative bacteria and fungus. Dynamic light scattering for sizing, zeta potential analysis, polydispersity, and colloidal stability over time characterized Gr NPs/PDDA dispersions, and plating and colony-forming units counting determined their microbicidal activity. Cell viabilities of Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in the presence of the combinations were reduced by 6, 7, and 7 logs, respectively, at 10 μM Gr/10 μg·mL−1 PDDA, 0.5 μM Gr/0. 5μg·mL−1 PDDA, and 0.5 μM Gr/0.5 μg·mL−1 PDDA, respectively. In comparison to individual Gr doses, the combinations reduced doses by half (S. aureus) and a quarter (C. albicans); in comparison to individual PDDA doses, the combinations reduced doses by 6 times (P. aeruginosa) and 10 times (C. albicans). Gr in supported or free cationic lipid bilayers reduced Gr activity against S. aureus due to reduced Gr access to the pathogen. Facile Gr NPs/PDDA disassembly favored access of each agent to the pathogen: PDDA suctioned the pathogen cell wall facilitating Gr insertion in the pathogen cell membrane. Gr NPs/PDDA differential cytotoxicity suggested the possibility of novel systemic uses for the combination.
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2
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Kang Z, Ding G, Meng Z, Meng Q. The rational design of cell-penetrating peptides for application in delivery systems. Peptides 2019; 121:170149. [PMID: 31491454 DOI: 10.1016/j.peptides.2019.170149] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/30/2019] [Accepted: 09/02/2019] [Indexed: 12/20/2022]
Abstract
Cell penetrating peptides (CPPs) play a crucial role in the transportation of bioactive molecules. Although CPPs have been used widely in various delivery systems, further applications of CPPs are hampered by several drawbacks, such as high toxicity, low delivery efficiency, proteolytic instability and poor specificity. To design CPPs with great cell-penetrating ability, physicochemical properties and safety, researchers have tried to develop new methods to overcome the defects of CPPs. Briefly, (1) the side chain of arginine containing the guanidinium group is essential for the facilitation of cellular uptake; (2) the hydrophobic counterion complex around the guanidinium-rich backbone can "coat" the highly cationic structure with lipophilic moieties and act as an activator; (3) the conformation-constrained strategy was pursued to shield the peptide, thereby impeding access of the proteolytic enzyme; (4) targeting strategies can increase cell-type specificity of CPPs. In this review, the above four aspects were discussed in detail.
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Affiliation(s)
- Ziyao Kang
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China
| | - Guihua Ding
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China
| | - Zhao Meng
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China
| | - Qingbin Meng
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing, 100850, China; Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin, 300071, China; Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China.
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3
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Bhunia D, Mondal P, Das G, Saha A, Sengupta P, Jana J, Mohapatra S, Chatterjee S, Ghosh S. Spatial Position Regulates Power of Tryptophan: Discovery of a Major-Groove-Specific Nuclear-Localizing, Cell-Penetrating Tetrapeptide. J Am Chem Soc 2018; 140:1697-1714. [DOI: 10.1021/jacs.7b10254] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Debmalya Bhunia
- Organic
and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
| | - Prasenjit Mondal
- Organic
and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
| | - Gaurav Das
- Organic
and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
| | - Abhijit Saha
- Organic
and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
| | - Pallabi Sengupta
- Department
of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054, India
| | - Jagannath Jana
- Department
of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054, India
| | - Saswat Mohapatra
- Organic
and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
| | - Subhrangsu Chatterjee
- Department
of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054, India
| | - Surajit Ghosh
- Organic
and Medicinal Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
- Academy of Scientific & Innovative Research (AcSIR), CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700032, India
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4
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Bechara C, Sagan S. Cell-penetrating peptides: 20 years later, where do we stand? FEBS Lett 2013; 587:1693-702. [PMID: 23669356 DOI: 10.1016/j.febslet.2013.04.031] [Citation(s) in RCA: 638] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 04/22/2013] [Accepted: 04/29/2013] [Indexed: 01/01/2023]
Abstract
Twenty years ago, the discovery of peptides able to cross cellular membranes launched a novel field in molecular delivery based on these non-invasive vectors, most commonly called cell-penetrating peptides (CPPs) or protein transduction domains (PTDs). These peptides were shown to efficiently transport various biologically active molecules inside living cells, and thus are considered promising devices for medical and biotechnological developments. Moreover, CPPs emerged as potential tools to study the prime mechanisms of cellular entry across the plasma membrane. This review is dedicated to CPP fundamentals, with an emphasis on the molecular requirements and mechanism of their entry into eukaryotic cells.
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Affiliation(s)
- Chérine Bechara
- UPMC-Univ Paris 6, Laboratoire des BioMolecules, cc 182, UMR 7203 CNRS, ENS, Paris, France.
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5
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Proposed Mechanism for H(II) Phase Induction by Gramicidin in Model Membranes and Its Relation to Channel Formation. Biophys J 2010; 53:111-7. [PMID: 19431714 DOI: 10.1016/s0006-3495(88)83072-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A model is proposed for the molecular mechanism of H(II) phase induction by gramicidin in model membranes. The model describes the sequence of events that occurs upon hydration of a mixed lipid/gramicidin film, relating them to gramicidin channel formation and to relevant literature on gramicidin and lipid structure.
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6
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Kelkar DA, Chattopadhyay A. The gramicidin ion channel: A model membrane protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:2011-25. [PMID: 17572379 DOI: 10.1016/j.bbamem.2007.05.011] [Citation(s) in RCA: 264] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 05/09/2007] [Accepted: 05/10/2007] [Indexed: 02/07/2023]
Abstract
The linear peptide gramicidin forms prototypical ion channels specific for monovalent cations and has been extensively used to study the organization, dynamics and function of membrane-spanning channels. In recent times, the availability of crystal structures of complex ion channels has challenged the role of gramicidin as a model membrane protein and ion channel. This review focuses on the suitability of gramicidin as a model membrane protein in general, and the information gained from gramicidin to understand lipid-protein interactions in particular. Special emphasis is given to the role and orientation of tryptophan residues in channel structure and function and recent spectroscopic approaches that have highlighted the organization and dynamics of the channel in membrane and membrane-mimetic media.
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Affiliation(s)
- Devaki A Kelkar
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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7
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Kelkar DA, Chattopadhyay A. Modulation of gramicidin channel conformation and organization by hydrophobic mismatch in saturated phosphatidylcholine bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1103-13. [PMID: 17321493 DOI: 10.1016/j.bbamem.2007.01.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 01/18/2007] [Accepted: 01/22/2007] [Indexed: 11/25/2022]
Abstract
The matching of hydrophobic lengths of integral membrane proteins and the surrounding lipid bilayer is an important factor that influences both structure and function of integral membrane proteins. The ion channel gramicidin is known to be uniquely sensitive to membrane properties such as bilayer thickness and membrane mechanical properties. The functionally important carboxy terminal tryptophan residues of gramicidin display conformation-dependent fluorescence which can be used to monitor gramicidin conformations in membranes [S.S. Rawat, D.A. Kelkar, A. Chattopadhyay, Monitoring gramicidin conformations in membranes: a fluorescence approach, Biophys. J. 87 (2004) 831-843]. We have examined the effect of hydrophobic mismatch on the conformation and organization of gramicidin in saturated phosphatidylcholine bilayers of varying thickness utilizing the intrinsic conformation-dependent tryptophan fluorescence. Our results utilizing steady state and time-resolved fluorescence spectroscopic approaches, in combination with circular dichroism spectroscopy, show that gramicidin remains predominantly in the channel conformation and gramicidin tryptophans are at the membrane interfacial region over a range of mismatch conditions. Interestingly, gramicidin conformation shifts toward non-channel conformations in extremely thick gel phase membranes although it is not excluded from the membrane. In addition, experiments utilizing self quenching of tryptophan fluorescence indicate peptide aggregation in thicker gel phase membranes.
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Affiliation(s)
- Devaki A Kelkar
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India
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8
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Biswas SC, Rananavare SB, Hall SB. Effects of gramicidin-A on the adsorption of phospholipids to the air-water interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1717:41-9. [PMID: 16242116 PMCID: PMC3490622 DOI: 10.1016/j.bbamem.2005.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 08/31/2005] [Accepted: 09/06/2005] [Indexed: 10/25/2022]
Abstract
Prior studies suggest that the hydrophobic surfactant proteins, SP-B and SP-C, promote adsorption of the lipids in pulmonary surfactant to an air-water interface by stabilizing a negatively curved rate-limiting structure that is intermediate between bilayer vesicles and the surface film. This model predicts that other peptides capable of stabilizing negative curvature should also promote lipid adsorption. Previous reports have shown that under appropriate conditions, gramicidin-A (GrA) induces dioleoyl phosphatidylcholine (DOPC), but not dimyristoyl phosphatidylcholine (DMPC), to form the negatively curved hexagonal-II (H(II)) phase. The studies reported here determined if GrA would produce the same effects on adsorption of DMPC and DOPC that the hydrophobic surfactant proteins have on the surfactant lipids. Small angle X-ray scattering and (31)P-nuclear magnetic resonance confirmed that at the particular conditions used to study adsorption, GrA induced DOPC to form the H(II) phase, but DMPC remained lamellar. Measurements of surface tension showed that GrA in vesicles produced a general increase in the rate of adsorption for both phospholipids. When restricted to the interface, however, in preexisting films, GrA with DOPC, but not with DMPC, replicated the ability of the surfactant proteins to promote adsorption of vesicles containing only the lipids. The correlation between the structural and functional effects of GrA with the two phospholipids, and the similar effects on adsorption of GrA with DOPC and the hydrophobic surfactant proteins with the surfactant lipids fit with the model in which SP-B and SP-C facilitate adsorption by stabilizing a rate-limiting intermediate with negative curvature.
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Affiliation(s)
- Samares C. Biswas
- Departments of Molecular Biology and Biochemistry, Medicine, and Physiology and Pharmacology, Mail Code NRC-3, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Shankar B. Rananavare
- Department of Chemistry, Portland State University, Portland, OR 97207 and Department of Electrical and Computer Engineering, Oregon Graduate Institute of Science and Engineering, Beaverton, OR 97206, USA
| | - Stephen B. Hall
- Departments of Molecular Biology and Biochemistry, Medicine, and Physiology and Pharmacology, Mail Code NRC-3, Oregon Health & Science University, Portland, OR 97239-3098, USA
- Corresponding author. Tel.: +1 503 494 6667; fax: +1 503 494 7368. (S.B. Hall)
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9
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Abstract
Gramicidin A was studied by continuous wave electron spin resonance (CW-ESR) and by double-quantum coherence electron spin resonance (DQC-ESR) in several lipid membranes (using samples that were macroscopically aligned by isopotential spin-dry ultracentrifugation) and vesicles. As a reporter group, the nitroxide spin-label was attached at the C-terminus yielding the spin-labeled product (GAsl). ESR spectra of aligned membranes containing GAsl show strong orientation dependence. In DPPC and DSPC membranes at room temperature the spectral shape is consistent with high ordering, which, in conjunction with the observed high polarity of the environment of the nitroxide, is interpreted in terms of the nitroxide moiety being close to the membrane surface. In contrast, spectra of GAsl in DMPC membranes indicate deeper embedding and tilt of the NO group. The GAsl spectrum in the DPPC membrane at 35 degrees C (the gel to Pbeta phase transition) exhibits sharp changes, and above this temperature becomes similar to that of DMPC. The dipolar spectrum from DQC-ESR clearly indicates the presence of pairs in DMPC membranes. This is not the case for DPPC, rapidly frozen from the gel phase; however, there are hints of aggregation. The interspin distance in the pairs is 30.9 A, in good agreement with estimates for the head-to-head GAsl dimer (the channel-forming conformation), which matches the hydrophobic thickness of the DMPC bilayer. Both DPPC and DSPC, apparently as a result of hydrophobic mismatch between the dimer length and bilayer thickness, do not favor the channel formation in the gel phase. In the Pbeta and Lalpha phases of DPPC (above 35 degrees C) the channel dimer forms, as evidenced by the DQC-ESR dipolar spectrum after rapid freezing. It is associated with a lateral expansion of lipid molecules and a concomitant decrease in bilayer thickness, which reduces the hydrophobic mismatch. A comparison with studies of dimer formation by other physical techniques indicates the desirability of using low concentrations of GA (approximately 0.4-1 mol %) accessible to the ESR methods employed in the study, since this yields non-interacting dimer channels.
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Affiliation(s)
- Boris G Dzikovski
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14583-1301, USA
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10
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Abstract
Gramicidin is an antibiotic peptide that can be incorporated into the monolayers of cell membranes. Dimerization through hydrogen bonding between gramicidin monomers in opposing leaflets of the membrane results in the formation of an iontophoretic channel. Surrounding phospholipids influence the gating properties of this channel. Conversely, gramicidin incorporation has been shown to affect the structure of spontaneously formed lipid assemblies. Using small-angle x-ray diffraction and model systems composed of phospholipids and gramicidin, the effects produced by gramicidin on lipid layers were measured. These measurements explore how peptides are able to modulate the spontaneous curvature properties of phospholipid assemblies. The reverse hexagonal, H(II), phase formed by dioleoylphosphatidylethanolamine (DOPE) monolayers decreased in lattice dimension with increasing incorporation of gramicidin. This indicated that gramicidin itself was adding negative curvature to the lipid layers. In this system, gramicidin was measured to have an apparent intrinsic radius of curvature, R0pgram, of -7.1 A. The addition of up to 4 mol% gramicidin in DOPE did not result in the monolayers becoming stiffer, as measured by the monolayer bending moduli. Dioleoylphosphatidylcholine (DOPC) alone forms the lamellar (L(alpha)) phase when hydrated, but undergoes a transition into the reverse hexagonal (H(II)) phase when mixed with gramicidin. The lattice dimension decreases systematically with increased gramicidin content. Again, this indicated that gramicidin was adding negative curvature to the lipid monolayers but the mixture behaved structurally much less consistently than DOPE/gramicidin. Only at 12 mol% gramicidin in dioleoylphosphatidylcholine could an apparent radius of intrinsic curvature of gramicidin (R0pgram) be estimated as -7.4 A. This mixture formed monolayers that were very resistant to bending, with a measured bending modulus of 115 kT.
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Affiliation(s)
- J A Szule
- Biological Sciences, Brock University, St. Catharines, Ontario, Canada, L2S 3A1
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11
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Costa-Filho AJ, Crepeau RH, Borbat PP, Ge M, Freed JH. Lipid-gramicidin interactions: dynamic structure of the boundary lipid by 2D-ELDOR. Biophys J 2003; 84:3364-78. [PMID: 12719265 PMCID: PMC1302896 DOI: 10.1016/s0006-3495(03)70060-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The use of 2D-electron-electron double resonance (2D-ELDOR) for the characterization of the boundary lipid in membrane vesicles of DPPC and gramicidin A' (GA) is reported. We show that 2D-ELDOR, with its enhanced spectral resolution to dynamic structure as compared with continuous-wave electron spin resonance, provides a reliable and useful way of studying lipid-protein interactions. The 2D-ELDOR spectra of the end-chain spin label 16-PC in DPPC/GA vesicles is composed of two components, which are assigned to the bulk lipids (with sharp auto peaks and crosspeaks) and to the boundary lipids (with broad auto peaks). Their distinction is clearest for higher temperatures and higher GA concentrations. The quantitative analysis of these spectra shows relatively faster motions and very low ordering for the end chain of the bulk lipids, whereas the boundary lipids show very high "y-ordering" and slower motions. The y-ordering represents a dynamic bending at the end of the boundary lipid acyl chain, which can then coat the GA molecules. These results are consistent with the previous studies by Ge and Freed (1999) using continuous-wave electron spin resonance, thereby supporting their model for GA aggregation and H(II) phase formation for high GA concentrations. Improved instrumental and simulation methods have been employed.
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Affiliation(s)
- Antonio J Costa-Filho
- Department of Chemistry and Chemical Biology, National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, NY 14853-1301 USA
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12
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Hinton J, Jordan B, Horne E. Molecular structure heterogeneity of gramicidin analogs incorporated into SDS micelles: a NMR study. J Mol Struct 2002. [DOI: 10.1016/s0022-2860(01)00736-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Mondal S, Ghosh S. Gramicidin A and its complexes with Cs+ and Tl+ ions in organic solvents. A study by steady state and time resolved emission spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2001; 60:12-24. [PMID: 11386676 DOI: 10.1016/s1011-1344(00)00138-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Gramicidin A (gr A), a linear pentadecapeptide containing four trp residues has been studied using steady state and time resolved fluorescence (at 298 K) and phosphorescence (at 77 K) in methanol (CH3OH), ethanol (C2H5OH), dimethyl sulfoxide (DMSO), 1,4-dioxane, 2-methyl tetrahydrofuran (2-MeTHF), ethanol/benzene (C2H5OH/C6H6) mixed solvent. Similar studies have also been carried out in CH3OH containing monovalent cations K+, Cs+, Tl+ and divalent cation Ca2+. Lambda(max) of fluorescence is found to be a good signature of the different forms having double helical structure [dh (1) to dh (4)] (J. Struct. Biol. 121 (1998) 123-141). Steady state and time resolved quenching studies of gr A by KI in CH3OH and DMSO and life time of the emitting singlet states of gr A support that gr A exists as a mixture of different forms of double helical (dh) structure [dh (1) to dh (4)] in CH3OH and as a random coil structure in DMSO. This study further indicates that emitting trp residue in DMSO is better shielded than that in CH3OH. Phosphorescence spectra of gr A at 77 K in CH3OH glass suggests that gr A retains a particular conformation dh (3) in this matrix. The phosphorescence spectra of gr A [conformation dh (4)] in 2-MeTHF at 77 K is further red shifted indicating that among all the dh forms, dh (4) has the emitting trp residue in most hydrophobic environment. The hydrophobicity of the emitting tryptophan environment is thus found to be in the order: dh (1)<dh (3)<dh (4). Since 2-MeTHF forms a clear glass at low temperature, it is thus possible to study the side chain arrangement of gr A dh (4) as a function of temperature. The phosphorescence spectra in different alcohol glassy matrix are in conformity with the observation of different side chain arrangement of gr A as one changes the polarity of alcohol. Steady state and time resolved quenching studies of gr A using Cs+ ion in CH3OH at 298 K clearly demonstrate the two binding sites for the metal ions and provide the value of equilibrium constant of the 'non-emitting' complex of gr A with Cs+ ion in the ground state. The observation of distinct red shift of the (0,0) band of the phosphorescence spectra of the complexes of gr A with K+, Cs+ and Tl+ ions at 77 K compared to that in CH3OH glass confirms the metal ion induced change of conformation in dh (3). The result also suggests that the emitting trp residues in the complexes are in somewhat more hydrophobic environment compared with that in the free gr A in CH3OH glass. The triplet state life time of these complexes indicate that the heavy metal ions Cs+ and Tl+ are within a Van der Waal's distance of emitting trp residue in gr A in CH3OH glass at 77 K so that they are capable of inducing increased spin-orbit coupling due to a heavy atom effect.
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Affiliation(s)
- S Mondal
- Department of Chemistry, Presidency College, Calcutta, India
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14
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Lohner K, Prenner EJ. Differential scanning calorimetry and X-ray diffraction studies of the specificity of the interaction of antimicrobial peptides with membrane-mimetic systems. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1462:141-56. [PMID: 10590306 DOI: 10.1016/s0005-2736(99)00204-7] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Interest in biophysical studies on the interaction of antimicrobial peptides and lipids has strongly increased because of the rapid emergence of antibiotic-resistant bacterial strains. An understanding of the molecular mechanism(s) of membrane perturbation by these peptides will allow a design of novel peptide antibiotics as an alternative to conventional antibiotics. Differential scanning calorimetry and X-ray diffraction studies have yielded a wealth of quantitative information on the effects of antimicrobial peptides on membrane structure as well as on peptide location. These studies clearly demonstrated that antimicrobial peptides show preferential interaction with specific phospholipid classes. Furthermore, they revealed that in addition to charge-charge interactions, membrane curvature strain and hydrophobic mismatch between peptides and lipids are important parameters in determining the mechanism of membrane perturbation. Hence, depending on the molecular properties of both lipid and peptide, creation of bilayer defects such as phase separation or membrane thinning, pore formation, promotion of nonlamellar lipid structures or bilayer disruption by the carpet model or detergent-like action, may occur. Moreover, these studies suggest that these different processes may represent gradual steps of membrane perturbation. A better understanding of the mutual dependence of these parameters will help to elucidate the molecular mechanism of membrane damage by antimicrobial peptides and their target membrane specificity, keys for the rationale design of novel types of peptide antibiotics.
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Affiliation(s)
- K Lohner
- Institut für Biophysik und Röntgenstrukturforschung, Osterreichische Akademie der Wissenschaften, Steyrergasse 17/VI, A-8010, Graz, Austria.
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15
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Ge M, Freed JH. Electron-spin resonance study of aggregation of gramicidin in dipalmitoylphosphatidylcholine bilayers and hydrophobic mismatch. Biophys J 1999; 76:264-80. [PMID: 9876140 PMCID: PMC1302517 DOI: 10.1016/s0006-3495(99)77195-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The effect of aggregation of gramicidin A' (GA) on the phase structure of dipalmitoylphosphatidylcholine (DPPC) multilamellar vesicles was studied by cw-ESR using a chain-labeled lipid (16PC) at temperatures between 30 degrees and 45 degreesC that span the main phase transition of DPPC. Boundary lipids were observed only in dispersions with GA/DPPC molar ratios >1:15, where GA aggregates. Detailed fits by nonlinear least squares (NLLS) methods are consistent with the boundary lipid being characterized by a large negative order parameter ( approximately -0.4), indicative of a dynamic bending of the end of the acyl chain, and a substantially reduced motion, about an order of magnitude slower than that of the bulk lipid. The NLLS analysis compares favorably with a recent two-dimensional Fourier transform ESR study on DPPC/GA vesicles, which accurately discerned the bulk lipid. The detailed ESR observables are discussed in terms of the ordering effect of GA at low concentration of GA, the dissociation of the GA channel and the dynamic bending of the end chain segment of boundary lipid at high concentration of GA, and of HII phase formation induced by GA. It is suggested that these phenomena can be interpreted in terms of the combined effects of partial dehydration of the lipid headgroup by the GA and of the hydrophobic mismatch between GA and DPPC molecules. Substantial hysteresis is observed for heating versus cooling cycles, but only for a GA/DPPC molar ratio >1:15. This is consistent with the aggregation of GA molecules at high concentrations.
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Affiliation(s)
- M Ge
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA
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16
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Busath DD, Thulin CD, Hendershot RW, Phillips LR, Maughan P, Cole CD, Bingham NC, Morrison S, Baird LC, Hendershot RJ, Cotten M, Cross TA. Noncontact dipole effects on channel permeation. I. Experiments with (5F-indole)Trp13 gramicidin A channels. Biophys J 1998; 75:2830-44. [PMID: 9826605 PMCID: PMC1299956 DOI: 10.1016/s0006-3495(98)77726-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Gramicidin A (gA), with four Trp residues per monomer, has an increased conductance compared to its Phe replacement analogs. When the dipole moment of the Trp13 side chain is increased by fluorination at indole position 5 (FgA), the conductance is expected to increase further. gA and FgA conductances to Na+, K+, and H+ were measured in planar diphytanoylphosphatidylcholine (DPhPC) or glycerylmonoolein (GMO) bilayers. In DPhPC bilayers, Na+ and K+ conductances increased upon fluorination, whereas in GMO they decreased. The low ratio in the monoglyceride bilayer was not reversed in GMO-ether bilayers, solvent-inflated or -deflated bilayers, or variable fatty acid chain monoglyceride bilayers. In both GMO and DPhPC bilayers, fluorination decreased conductance to H+ but increased conductance in the mixed solution, 1 M KCl at pH 2.0, where K+ dominates conduction. Eadie-Hofstee plot slopes suggest similar destabilization of K+ binding in both lipids. Channel lifetimes were not affected by fluorination in either lipid. These observations indicate that fluorination does not change the rotameric conformation of the side chain. The expected difference in the rate-limiting step for transport through channels in the two bilayers qualitatively explains all of the above trends.
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Affiliation(s)
- D D Busath
- Zoology Department, Brigham Young University, Provo, Utah 84062, USA.
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17
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Abstract
Non-lamellar-forming lipids play an important role in determining the physical properties of membranes. They affect the activity of membrane proteins and peptides. In addition, peptides which lyse membranes as well as those which promote membrane fusion facilitate the formation of non-lamellar phases, either micelles, cubic or hexagonal phases. The relationship of these diverse effects on membrane curvature is discussed in relation to the function of certain peptides and proteins. Specific examples of ionophoric peptides, cytotoxic peptides and viral fusion peptides are given. In addition, we compare the modulation of the rate of photoisomerisation of an integral membrane protein, rhodopsin, by non-lamellar-forming lipids with the effects of these lipids on an amphitropic protein, protein kinase C. Among these diverse systems it is frequently observed that the modulation of biological activity can be described in terms of the effect of the peptide or protein on the relative stability of lamellar and non-lamellar structures.
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Affiliation(s)
- R M Epand
- Department of Biochemistry, McMaster University Health Sciences Centre, Hamilton, Ont. L8N 3Z5, Canada.
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18
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Girshman J, Greathouse DV, Koeppe RE, Andersen OS. Gramicidin channels in phospholipid bilayers with unsaturated acyl chains. Biophys J 1997; 73:1310-9. [PMID: 9284299 PMCID: PMC1181031 DOI: 10.1016/s0006-3495(97)78164-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In organic solvents gramicidin A (gA) occurs as a mixture of slowly interconverting double-stranded dimers. Membrane-spanning gA channels, in contrast, are almost exclusively single-stranded beta(6,3)-helical dimers. Based on spectroscopic evidence, it has previously been concluded that the conformational preference of gA in phospholipid bilayers varies as a function of the degree of unsaturation of the acyl chains. Double-stranded pi pi(5,6)-helical dimers predominate (over single-stranded beta(6,3)-helical dimers) in lipid bilayer membranes with polyunsaturated acyl chains. We therefore examined the characteristics of channels formed by gA in 1-palmitoyl-2-oleoylphosphatidylcholine/n-decane, 1,2-dioleoylphosphatidylcholine/n-decane, and 1,2-dilinoleoylphosphatidylcholine/n-decane bilayers. We did not observe long-lived channels that could be conducting double-stranded pi pi(5,6)-helical dimers in any of these different membrane environments. We conclude that the single-stranded beta(6,3)-helical dimer is the only conducting species in these bilayers. Somewhat surprisingly, the average channel duration and channel-forming potency of gA are increased in dilinoleoylphosphatidylcholine/n-decane bilayers compared to 1-palmitoyl-2-oleoylphosphatidylcholine/n-decane and dioleoylphosphatidylcholine/n-decane bilayers. To test for specific interactions between the aromatic side chains of gA and the acyl chains of the bilayer, we examined the properties of channels formed by gramicidin analogues in which the four tryptophan residues were replaced with naphthylalanine (gN), tyrosine (gT), and phenylalanine (gM). The results show that all of these analogue channels experience the same relative stabilization when going from dioleoylphosphatidylcholine to dilinoleoylphosphatidylcholine bilayers.
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Affiliation(s)
- J Girshman
- Department of Physiology and Biophysics, Cornell University Medical College, New York, New York 10021, USA
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19
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Otten-Kuipers MA, Franssen FF, Nieuwenhuijs H, Overdulve JP, Roelofsen B, Op den Kamp JA. Effect of tryptophan-N-formylated gramicidin on growth of Plasmodium berghei in mice. Antimicrob Agents Chemother 1997; 41:1778-82. [PMID: 9257760 PMCID: PMC164004 DOI: 10.1128/aac.41.8.1778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The effect of tryptophan-N-formylated gramicidin (NFG) on the growth of Plasmodium berghei in mice was tested in three different experiments. NFG was shown to be capable of inhibiting the growth of the parasite in a dose-dependent way, although its action did not result in elimination of the parasite and was only temporary, preventing mice from early death, presumably due to cerebral malaria, but not from fatal generalized malaria. Intriguingly, a similar observation was made with two other drugs, (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine, an inhibitor of viral and eukaryotic DNA polymerases, and the presumed topoisomerase II inhibitor, a bisquaternary quinolinium salt. A rise in the level of parasitemia after 8 days, despite continued treatment, was not due to parasite-induced reticulocytosis, as demonstrated in experiments in which this condition was induced artificially. NFG was added in the form of lipid vesicles in which the peptide had been incorporated. The inhibitory action of NFG was not modulated by the lipid composition of the vesicles. Control experiments did not demonstrate any toxicity of NFG when it was administered in lipid vesicles. The main observation is that NFG is able to inhibit the growth of a malaria parasite in vivo at concentrations that are well tolerated by the host.
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Affiliation(s)
- M A Otten-Kuipers
- Department of Lipid Biochemistry, Centre for Biomembranes and Lipid Enzymology, Utrecht University, The Netherlands
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20
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Epand RM. Chapter 6 Modulation of Lipid Polymorphism by Peptides. CURRENT TOPICS IN MEMBRANES 1997. [DOI: 10.1016/s0070-2161(08)60210-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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21
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Berlose JP, Convert O, Derossi D, Brunissen A, Chassaing G. Conformational and associative behaviours of the third helix of antennapedia homeodomain in membrane-mimetic environments. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 242:372-86. [PMID: 8973656 DOI: 10.1111/j.1432-1033.1996.0372r.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The third helix of antennapedia homeodomain pAntp-(43-58) can translocate through cell membrane and has been used as an intracellular vehicle for delivering peptides and oligonucleotides. The conformational and associative behaviour of two peptidic vectors pAntp-(43-58) and [Pro50] pAntp-(43-58) has been analyzed by different biophysical methods. pAntp-(43-58) adopts an amphipathic helical structure in 30% (by vol.) hexafluoroisopropanol, in perfluoro-tert-butanol and in the presence of SDS micelles. CD spectra indicate that the conformation of [Pro50]pAntp-(43-58) in contrast to pAntp-(43-58) is independent of the media used. 1H-NMR spectroscopy in SDS micelles or in perfluoro-tert-butanol allows detection of aggregated peptides probably in a ribbon 2(7) type conformation. These conformations became the predominant structure when Gln50 was replaced by Pro50. Interproton-distance restraints derived from NOE measurements have been classified in two groups corresponding to two types of structures: alpha-helix and essentially extended structures. Consecutive CH alpha (i)/ CH alpha (i + 1) NOEs are only compatible with aggregates. Simulated annealing calculation of dimeric structure agrees with phi and psi angles in the beta-sheet and gamma-turn regions. Fluorescence spectroscopy analysis has shown that the indole groups of both peptides penetrate into SDS micelles; both peptides also induce the formation of micelles at very low concentration of SDS (20 microM). Similar interaction was observed with reverse-phase micelles made of bis(2-ethyhexyl) sodium sulfosuccinate and small unilamellar vesicles (SUV) made of a mixture of phosphatidylcholine/phosphatidylserine. 31P-NMR of vesicles (SUV and large unilamellar vesicles) indicated that the addition of pAntp analogues did not affect the size of phosphatidylcholine/phosphatidylserine vesicles. The addition of pAntp analogues to lipidic dispersions modulates lipid polymorphism in different ways depending on the mixtures of acidic lipids.
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Affiliation(s)
- J P Berlose
- Laboratoire de Chimie Organique Biologique, URA CNRS 493, Université P. et M. Curie, Paris, France
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22
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Otten-Kuipers MA, Beumer TL, Kronenburg NA, Roelofsen B, Op den Kamp JA. Effects of gramicidin and tryptophan-N-formylated gramicidin on the sodium and potassium content of human erythrocytes. Mol Membr Biol 1996; 13:225-32. [PMID: 9116761 DOI: 10.3109/09687689609160600] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In order to get a better understanding in the mechanism by which tryptophan-N-formylated gramicidin (NFG) and gramicidin kill the malaria parasite Plasmodium falciparum in vitro, we studied the capacity of these peptides to change the potassium, as well as the sodium, composition of normal human erythrocytes, and their ability to cause cell lysis. It is shown that both peptides are able to induce potassium leakage from, and sodium flux into, erythrocytes in such a manner that it is most likely that they are able to form cation channels in the membrane of these cells. For both peptides, potassium efflux proceeds at a faster rate than sodium influx, but this difference is greater for NFG than for gramicidin. This explains the observation that gramicidin is more lytic than NFG is, even when comparing concentrations that show the same antimalarial activity. The finding that gramicidin is approximately 10 times more active than NFG in causing potassium efflux from normal erythrocytes, as well as in killing the malaria parasite, supports the hypothesis that peptide-induced parasite death is related to their capacity to induce potassium leakage from infected erythrocytes. Finally, the observation that erythrocytes are able to restore their normal ion contents after losing more than 50% of their potassium content by incubation with NFG or gramicidin, suggests that, in vivo, and upon treatment with drug concentrations that cause full inhibition of parasite growth, these cells would not be irreversibly damaged by action of the drugs.
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Affiliation(s)
- M A Otten-Kuipers
- Department of Lipid Biochemistry, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, The Netherlands
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23
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Salom D, Abad C. Chromatographic purification and characterization of synthetic tryptophan-substituted gramicidin A analogues. J Chromatogr A 1996. [DOI: 10.1016/0021-9673(96)84623-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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24
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Epand RM, Shai Y, Segrest JP, Anantharamaiah GM. Mechanisms for the modulation of membrane bilayer properties by amphipathic helical peptides. Biopolymers 1995; 37:319-38. [PMID: 7632881 DOI: 10.1002/bip.360370504] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The amphipathic helix, in which hydrophobic and hydrophilic residues are grouped on opposing faces, is a structural motif found in many peptides and proteins that bind to membranes. One of the physical properties of membranes that can be altered by the binding of amphipathic helices is membrane monolayer curvature strain. Class A amphipathic helices, which are present in exchangeable plasma lipoproteins, can stabilize membranes by reducing negative monolayer curvature strain; proline-punctuated class A amphipathic helical segments are particularly effective in this regard. This property is suggested to be associated with some of the beneficial biological effects of this protein. On the other hand, lytic amphipathic helical peptides can act by increasing negative curvature strain or by forming pores composed of helical clusters. Thus, different amphipathic helical peptides can be membrane stabilizing or be lytic to membranes, depending on the structural motif of the helix, which in turn determines the nature of its association with membranes. Features of these peptides that are responsible for their specific properties are discussed.
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Affiliation(s)
- R M Epand
- Department of Biochemistry, McMaster University, Hamilton, ON, Canada
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25
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Otten-Kuipers MA, Roelofsen B, Op den Kamp JA. Stage-dependent effects of analogs of gramicidin A on the growth of Plasmodium falciparum in vitro. Parasitol Res 1995; 81:26-31. [PMID: 7536920 DOI: 10.1007/bf00932413] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Tryptophan-N-formylated gramicidin A, a nonhemolytic derivative of the toxic peptide antibiotic gramicidin A, has previously been shown to induce potassium leakage from Plasmodium falciparum-infected erythrocytes in vitro and to inhibit the growth of the parasite. In the present study the antimalarial activities of two other nonhemolytic derivatives of gramicidin A, viz., acylated gramicidin A and desformylated gramicidin A, were tested and compared with those of gramicidin A and tryptophan-N-formylated gramicidin A. The 50% growth-inhibitory concentrations (IC50 values) of the four compounds varied from 0.3 to 18.3 nM, and complete growth inhibition was detected within one parasitic growth cycle. Using highly synchronized cultures of P. falciparum, it was furthermore shown that the gramicidin analogs are inhibitory to all developmental stages of the parasite, although their efficiency in accomplishing growth inhibition was found, as expected, to be clearly stage-dependent and to increase with the age of the parasite.
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Affiliation(s)
- M A Otten-Kuipers
- Department of Lipid Biochemistry, Utrecht University, The Netherlands
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26
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Vogt TC, Killian JA, De Kruijff B. The influence of acylation on the lipid structure modulating properties of the transmembrane polypeptide gramicidin. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1193:55-61. [PMID: 7518694 DOI: 10.1016/0005-2736(94)90332-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In order to get insight into the effect of acylation of a transmembrane polypeptide on the interaction of the polypeptide with the membrane lipids we used 31P-NMR to investigate the influence of acylated gramicidins on the polymorphic phase behavior of hydrated dispersions of 1-palmitoyllysophosphatidylcholine (lyso-PC), 1,2-dioleoylphosphatidylcholine (DOPC) and 1,2-dielaidoylphosphatidylethanolamine (DEPE). Palmitoylgramicidin induces a micelle to extended bilayer organization in lyso-PC with a slightly lower efficiency than the parent gramicidin molecule. In DOPC and DEPE acylgramicidins induce the formation of HII phase at the expense of a bilayer organization with a similar high efficiency as gramicidin. The ability of acylgramicidin to induce lipid mixing between vesicles prepared of DOPC was decreased relative to gramicidin. The results are discussed in the light of the proposed models for gramicidin-induced HII phase formation and emphasize that gramicidin itself has a very strong lipid structure modulating activity.
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Affiliation(s)
- T C Vogt
- Utrecht University, Center for Biomembranes, The Netherlands
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27
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Greathouse DV, Hinton JF, Kim KS, Koeppe RE. Gramicidin A/short-chain phospholipid dispersions: chain length dependence of gramicidin conformation and lipid organization. Biochemistry 1994; 33:4291-9. [PMID: 7512381 DOI: 10.1021/bi00180a025] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Gramicidin-lipid interactions were investigated using diacylphosphatidylcholines that contained two identical acyl chains of varying length, between 6 and 14 carbons. The gramicidin A (gA) conformation was monitored by circular dichroism (CD) spectroscopy and high-performance size-exclusion chromatography, and the lipid organization was investigated using 31P and 1H NMR spectroscopy and negative-stain electron microscopy. Diacylphosphatidylcholine (PC) lipids with chain lengths between 4 and 8 carbons have been previously shown to have a micellar organization in aqueous solution [Lin, T.-L., et al. (1986) J. Am. Chem. Soc. 108, 3499-3507]. CD spectra of aqueous gA/lipid dispersions, at a ratio of 1:28, demonstrated that the channel conformation of gA can be readily obtained when the acyl chain length is > or = 10, but not when the chain length is < or = 7. Size-exclusion chromatography revealed that the fraction of gA that could easily be dissociated into monomers in the dispersions increased with increasing acyl chain length, in agreement with the CD results. For a chain length of 8, the results were intermediate. The formation of the channel structure was found to depend on the "solvent-history", the temperature, the gA and lipid concentrations, the gA:lipid ratio, and consequently on the method of sample preparation. 1H and 31P NMR results suggest that codispersed gA increases the size of dioctanoyl-PC aggregates, but not of dihexanoyl-PC micelles. Negative-stain electron microscopy directly supports these findings. Dihexanoyl-PC (28 mM) was able to solubilize 1 mM gA in H2O, but the gA was not in the "channel" conformation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D V Greathouse
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville 72701
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28
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Daragan VA, Ilyina E, Mayo KH. Effects of molecular association on structure and dynamics of a collagenous peptide. Biopolymers 1993; 33:521-33. [PMID: 8467063 DOI: 10.1002/bip.360330403] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Peptide GVKGDKGNPGWPGAPY from the triple-helix domain of type IV collagen aggregates in solution at a critical aggregation concentration of 18 mM. This molecular self-association process is investigated by 1H- and 13C-nmr spectroscopy. As a function of increasing peptide concentration, selective 1H resonances are cooperatively chemically shifted by up to 0.04 ppm to apparently saturable values at high concentration. Pulsed field gradient nmr was used to derive translation diffusion constants that, as the peptide concentration is increased, also cooperatively and monotonically decrease to an apparent limiting value. An average number of 6 monomer units per aggregate have been estimated from diffusion constant and 13C relaxation data. Comparative 1H nuclear Overhauser effect spectroscopy (NOESY) spectra accumulated at high and low peptide concentrations suggest that average internuclear distances are decreased as a result of peptide association. 13C-nmr multiple spin-lattice relaxation and 13C-[1H] NOE effects on 13C-enriched glycine methylene positions in the peptide demonstrate that overall molecular tumbling and backbone internal motions are attenuated in the aggregate state. Lowering the solution pD from pD 6 to pD 2 disrupts the aggregate state, suggesting a role for electrostatic interactions in the association process. Based on thermodynamic considerations, hydrophobic interactions also probably act to stabilize the aggregate state. These data are discussed in terms of an nmr/NOE constrained computer-modeled structure of the peptide.
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Affiliation(s)
- V A Daragan
- Jefferson Cancer Institute, Department of Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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29
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Affiliation(s)
- J A Killian
- Department of Biochemistry of Membranes, University of Utrecht, Netherlands
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30
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Cifu AS, Koeppe RE, Andersen OS. On the supramolecular organization of gramicidin channels. The elementary conducting unit is a dimer. Biophys J 1992; 61:189-203. [PMID: 1371703 PMCID: PMC1260233 DOI: 10.1016/s0006-3495(92)81826-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The question, whether the conducting channels formed by the linear gramicidins are dimers (as is generally believed) or tetramers (as has been recently proposed [Stark G., M. Strässle, and Z. Takacz. 1986. J. Membr. Biol. 89:23-37; Strässle, M., G. Stark, M. Wilhelm, P. Daumas, F. Heitz, and R. Lazaro. 1989. Biochim. Biophys. Acta. 980:305-314]) has been addressed in single-channel experiments. The experimental approach was based on the ability of electrophysiological (single-channel) experiments to resolve the number of hybrid channel types that could form between gramicidin A or C and O-pyromellityl-gramicidin A or C (in which a pyromellitic acid residue has been esterified to the ethanolamine-OH group [Apell, H.-J., E. Bamberg, H. Alpes, and P. Läuger. 1977. J. Membr. Biol. 31:171-188]). The presence of the bulky, negatively charged pyromellityl group at the channel entrances endows the hybrid channels with characteristically different features and thus facilitates the resolution of the different hybrid channel types. Only two hybrid channel types were detected, indicating that the conducting channels are membrane-spanning dimers. There was likewise no evidence for lateral association between conducting channels and nonconducting monomers. These results can be reconciled with those of Stark et al. (op. cit.) if gramicidin channel formation involves a (slow) folding into beta 6.3-helical monomers followed by the dimerization step.
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Affiliation(s)
- A S Cifu
- Department of Physiology and Biophysics, Cornell University Medical College, New York, New York 10021
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31
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Epand RM, Cheetham JJ, Epand RF, Yeagle PL, Richardson CD, Rockwell A, Degrado WF. Peptide models for the membrane destabilizing actions of viral fusion proteins. Biopolymers 1992; 32:309-14. [PMID: 1623124 DOI: 10.1002/bip.360320403] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The fusion of enveloped viruses to target membranes is promoted by certain viral fusion proteins. However, many other proteins and peptides stabilize bilayer membranes and inhibit membrane fusion. We have evaluated some characteristics of the interaction of peptides that are models of segments of measles and influenza fusion proteins with membranes. Our results indicate that these models of the fusogenic domains of viral fusion proteins promote conversion of model membrane bilayers to nonbilayer phases. This is opposite to the effects of peptides and proteins that inhibit viral fusion. A peptide model for the fusion segment of the HA protein of influenza increased membrane leakage as well as promoted the formation of nonbilayer phases upon acidification from pH 7-5. We analyze the gross conformational features of the peptides, and speculate on how these conformational features relate to the structures of the intact proteins and to their role in promoting membrane fusion.
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Affiliation(s)
- R M Epand
- Department of Biochemistry, McMaster University Health Sciences Centre, Hamilton, Ontario, Canada
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32
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Vogt TC, Killian JA, Demel RA, De Kruijff B. Synthesis of acylated gramicidins and the influence of acylation on the interfacial properties and conformational behavior of gramicidin A. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1069:157-64. [PMID: 1718430 DOI: 10.1016/0005-2736(91)90118-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Five gramicidin A analogs were synthesized in which various acyl chains, differing in length and unsaturation, were covalently coupled to the C-terminal ethanolamine group. The analogs were characterized by various spectroscopic techniques and their molecular properties were investigated using monolayer techniques and circular dichroism. It is demonstrated that neither the interfacial properties nor the conformational behavior of gramicidin A at the air/water interface are seriously affected upon acylation. It is proposed that at the limiting area the gramicidin molecule is oriented with its C-terminus towards the subphase with the covalently coupled acylchain located parallel to the helical axis in between the protruding tryptophans. Circular dichroism experiments, in which gramicidin-containing vesicles were prepared from different organic solvents, indicate that the presence of a covalently coupled fatty acylchain tends to stabilize the beta 6.3 helical conformation. It is demonstrated that, like for gramicidin A, also for the acylgramicidins the single-stranded beta 6.3 helical conformation, or channel conformation, is the preferred conformation upon incorporation in bilayers.
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Affiliation(s)
- T C Vogt
- Centre for Biomembranes and Lipid Enzymology, State University Utrecht, The Netherlands
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33
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Tournois H, de Kruijff B. Polymorphic phospholipid phase transitions as tools to understand peptide-lipid interactions. Chem Phys Lipids 1991; 57:327-40. [PMID: 1711420 DOI: 10.1016/0009-3084(91)90084-o] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effect of peptides on bilayer----non-bilayer phase transitions can be used as a tool to investigate the molecular aspects of peptide-lipid interactions. In this contribution the action on membranes of the peptide antibiotic gramicidin A and the bee venom component melittin are compared. Although the known structures and locations of these peptides upon membrane binding are very different, their actions on membranes show striking parallels. A general model is proposed that explains the seemingly complex peptide-lipid interactions by making use of simple concepts.
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Affiliation(s)
- H Tournois
- aATO Agrotechnology, Wageningen, The Netherlands
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34
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Jordi W, de Kroon AI, Killian JA, de Kruijff B. The mitochondrial precursor protein apocytochrome c strongly influences the order of the headgroup and acyl chains of phosphatidylserine dispersions. A 2H and 31P NMR study. Biochemistry 1990; 29:2312-21. [PMID: 2159798 DOI: 10.1021/bi00461a015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Deuterium and phosphorus nuclear magnetic resonance techniques were used to study the interaction of the mitochondrial precursor protein apocytochrome c with headgroup-deuterated (dioleoylphosphatidyl-L-[2-2H1]serine) and acyl chain deuterated (1,2-[11,11-2H2]dioleoylphosphatidylserine) dispersions. Binding of the protein to dioleoylphosphatidylserine liposomes results in phosphorus nuclear magnetic resonance spectra typical of phospholipids undergoing fast axial rotation in extended liquid-crystalline bilayers with a reduced residual chemical shift anisotropy and an increased line width. 2H NMR spectra on headgroup-deuterated dioleoylphosphatidylserine dispersions showed a decrease in quadrupolar splitting and a broadening of the signal on interaction with apocytochrome c. Addition of increasing amounts of apocytochrome c to the acyl chain deuterated dioleoylphosphatidylserine dispersions results in the gradual appearance of a second component in the spectra with a 44% reduced quadrupolar splitting. Such large reduction of the quadrupolar splitting has never been observed for any protein studied yet. The lipid structures corresponding to these two components could be separated by sucrose gradient centrifugation, demonstrating the existence of two macroscopic phases. In mixtures of phosphatidylserine and phosphatidylcholine similar effects are observed. The induction of a new spectral component with a well-defined reduced quadrupolar splitting seems to be confined to the N-terminus since addition of a small hydrophilic amino-terminal peptide (residues 1-38) also induces a second component with a strongly reduced quadrupolar splitting. A chemically synthesized peptide corresponding to amino acid residues 2-17 of the presequence of the mitochondrial protein cytochrome oxidase subunit IV also has a large perturbing effect on the order of the acyl chains, indicating that the observed effects may be a property shared by many mitochondrial precursor proteins. In contrast, binding of the mature protein, cytochrome c, to acyl chain deuterated phosphatidylserine dispersions has no effect on the deuterium and phosphorus nuclear magnetic resonance spectra, thereby demonstrating precursor-specific perturbation of the phospholipid order. The inability of holocytochrome c to perturb the phospholipid order is due to folding of this protein, since unfolding of cytochrome c by heat or urea treatment results in similar effects on dioleoylphosphatidylserine bilayers, as observed for the unfolded precursor. Implications of these data for the import of apocytochrome c into mitochondria will be discussed.
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Affiliation(s)
- W Jordi
- Centre for Biomembranes and Lipid Enzymology, State University of Utrecht, The Netherlands
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35
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Seddon JM. Structure of the inverted hexagonal (HII) phase, and non-lamellar phase transitions of lipids. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1031:1-69. [PMID: 2407291 DOI: 10.1016/0304-4157(90)90002-t] [Citation(s) in RCA: 775] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- J M Seddon
- Chemistry Department, The University, Southampton, U.K
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36
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Takeuchi H, Nemoto Y, Harada I. Environments and conformations of tryptophan side chains of gramicidin A in phospholipid bilayers studied by Raman spectroscopy. Biochemistry 1990; 29:1572-9. [PMID: 1692241 DOI: 10.1021/bi00458a031] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Raman spectroscopy has been used to investigate the hydrophobic interaction of the indole ring with the environments, the water accessibility to the N1H site, and the conformation about the C beta-C3 bond for the four tryptophan side chains of gramicidin A incorporated into phospholipid bilayers. Most of the tryptophan side chains of the head-to-head helical dimer transmembrane channel are strongly interacting with the lipid hydrocarbon chains, and the hydrophobic interactions for the rest increase with increasing hydrocarbon chain length of the lipid. One tryptophan side chain (probably Trp-15) is accessible to water molecules, another (Trp-9) is deeply buried in the bilayer and inaccessible, and the accessibilities of the remaining two (Trp-11 and Trp-13) depend on the bilayer thickness. The torsional angle about the C beta-C3 bond is found to be +/- 90 degrees for all the tryptophans irrespective of the membrane thickness. Binding of the sodium cation to the channel does not change the torsional angles but decreases the water accessibilities of two tryptophans (Trp-11 and Trp-13) considerably. In conjunction with a slight spectral change in the amide III region, it is suggested that the sodium binding causes a partial change in the main-chain conformation around Trp-11 and Trp-13, which results in the movements of these side chains toward the bilayer center. Two models consistent with the present Raman data are proposed for the tryptophan orientation in the dominant channel structure.
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Affiliation(s)
- H Takeuchi
- Pharmaceutical Institute, Tohoku University, Sendai, Japan
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37
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38
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Fraser PE, Rand RP, Deber CM. Bilayer-stabilizing properties of myelin basic protein in dioleoylphosphatidylethanolamine systems. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 983:23-9. [PMID: 2474328 DOI: 10.1016/0005-2736(89)90375-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
31P-NMR and X-ray diffraction techniques are used to study the comparative ability of myelin basic protein (MBP) vs. other basic proteins to convert hexagonal (HII) phases to stable lamellar (L alpha) structures. Pure dioleoylphosphatidylethanolamine (DOPE) at pH 9 and 7, and mixtures of DOPE/phosphatidylserine (PS) (95:5 and 80:20% w/w) at pH 7 were employed for this investigation. The polymorphic behavior of the lipid suspensions was evaluated in the presence and absence of several basic proteins (MBP, calf thymus histone, lysozyme, melittin) and the cationic polypeptide, polylysine (PL). Each of the proteins and PL was capable of binding the pure DOPE HII phase at pH 9 but with varying morphological consequences, i.e., lamellar stabilization (MBP, histone, PL), formation of new protein-DOPE HII phases (lysozyme) or lipid disordering/vesiculation (melittin). Reduction to pH 7 resulted in the dissociation of protein from DOPE - with the exception of melittin - and the reformation of a pure lipid HII phase. Additions of PS to DOPE at pH 7 facilitated protein binding, but among the proteins examined, only MBP was capable of converting the lipid suspension into a stable multilamellar form. Differences in the lipid morphology produced by each protein are discussed in terms of protein physicochemical characteristics. In addition, a possible relationship between MBP-lipid interactions and the stability of myelin sheath lipid multilayers is inferred from the significant bilayer-stabilizing capacity of MBP.
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Affiliation(s)
- P E Fraser
- Research Institute, Hospital for Sick Children, Ontario, Canada
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39
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Fields CG, Fields GB, Noble RL, Cross TA. Solid phase peptide synthesis of 15N-gramicidins A, B, and C and high performance liquid chromatographic purification. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1989; 33:298-303. [PMID: 2473960 DOI: 10.1111/j.1399-3011.1989.tb01285.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Four single-site 15N-labeled molecules of gramicidin have been synthesized using the 9-fluorenylmethoxycarbonyl method of solid phase peptide synthesis. Formylvaline was coupled as the N-terminal amino acid, and the peptide was cleaved from the resin with ethanolamine. Each synthesized gramicidin was purified in one step by semipreparative reverse phase high performance liquid chromatography and obtained in overall yields as high as 86%. The peptide was characterized by comparison with natural gramicidin using amino acid analysis, u.v. spectroscopy, and analytical high performance liquid chromatography.
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Affiliation(s)
- C G Fields
- Department of Chemistry, Florida State University, Tallahassee
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40
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Meulendijks GH, Sonderkamp T, Dubois JE, Nielen RJ, Kremers JA, Buck HM. The different influences of ether and ester phospholipids on the conformation of gramicidin A. A molecular modelling study. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 979:321-30. [PMID: 2466485 DOI: 10.1016/0005-2736(89)90252-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
With AMBER (assisted model building with energy refinement) molecular modelling techniques, the interactions between lipids which differ in the type of chain linkage (e.g., ether or ester) and gramicidin were approximated. It was found, theoretically, that replacement of the ester function in dipalmitoylphosphatidylcholine (DPPC) by an ether moiety induces a shift in the rotameric distribution of the Trp-15 side-chain in gramicidin A. Concomitantly, the channel entrance is contracted by approx. 0.4 A. The perturbation can be related to the strong hydrogen-bond formed between the lipid carbonyl group and the indole proton of the Trp-15 residue of gramicidin. In the ether lipid-gramicidin assembly a weaker H-bond is formed between Trp-15 and the phosphate moiety. To obtain a first indication of the influence of the strength of this H-bond on gramicidin A, a preliminary experimental study was set up. The transport properties of gramicidin A were studied using efflux measurements through vesicle walls containing ether and ester lipids, respectively. A change in the permeability of gramicidin A was found when ether lipids were added to a bilayer composed of the ester lipid dioleoylphosphatidylcholine (DOPC).
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Affiliation(s)
- G H Meulendijks
- Department of Organic Chemistry, Eindhoven University of Technology, The Netherlands
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41
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Tournois H, Gieles P, Demel R, de Gier J, de Kruijff B. Interfacial properties of gramicidin and gramicidin-lipid mixtures measured with static and dynamic monolayer techniques. Biophys J 1989; 55:557-69. [PMID: 2467699 PMCID: PMC1330509 DOI: 10.1016/s0006-3495(89)82849-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Gramicidin films at the air/water interface are shown to exhibit a phase transition at 225 A2/molecule which might be caused by either cluster formation, reorientation of molecules, conformational changes or multilayer formation. It is further shown that coupling of a charged group on either NH2- or COOH-terminus or elongation of the peptide by two amino acids, only slightly affects the surface area characteristics whereas modification of the tryptophans or even replacement of a single tryptophan by phenylalanine leads to drastic alterations in the surface-area characteristics and a (partial) loss of the phase transition demonstrating that the tryptophans play an important role in the interfacial behavior of gramicidin. The lack of a solvent history effect on the interfacial behavior indicates a rapid conformational interconversion of the peptide at the air/water interface. Gramicidin in mixtures with dioleoylphosphatidylcholine and lysopalmitoylphosphatidylcholine shows a condensing effect whereas gramicidin shows ideal mixing with dioleoylphosphatidylethanolamine. The condensing effect most likely is related to the aggregational state of the peptides which is different in phosphatidylcholines and phosphatidylethanolamines.
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Affiliation(s)
- H Tournois
- Centre of Biomembranes and Lipid Enzymology, University of Utrecht, The Netherlands
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42
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Killian JA, Prasad KU, Urry DW, de Kruijff B. A mismatch between the length of gramicidin and the lipid acyl chains is a prerequisite for HII phase formation in phosphatidylcholine model membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 978:341-5. [PMID: 2464375 DOI: 10.1016/0005-2736(89)90135-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Previously it was shown that gramicidin can induce HII phase formation in diacylphosphatidylcholine model membranes only when the lipid acyl chain length exceeds 16 carbon atoms (Van Echteld, C.J.A., De Kruijff, B., Verkleij, A.J., Leunissen-Bijvelt, J. and De Gier, J. (1982) Biochim. Biophys. Acta 692, 126-138). Using 31P-NMR and small angle X-ray diffraction we now demonstrate that upon increasing the length of gramicidin, the peptide loses its ability to induce HII phase formation in di-C18:1c-PC but not in the longer chained di-C22:1c-PC. It is concluded that a mismatch in length between gramicidin and the lipid acyl chains, when the latter would provide excess bilayer thickness, is a prerequisite for HII phase formation in phosphatidylcholine model membranes.
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Affiliation(s)
- J A Killian
- Centre for Biomembranes and Lipid Enzymology, University of Utrecht, The Netherlands
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43
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Killian JA, Urry DW. Conformation of gramicidin in relation to its ability to form bilayers with lysophosphatidylcholine. Biochemistry 1988; 27:7295-301. [PMID: 2462902 DOI: 10.1021/bi00419a018] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The ability of gramicidin to induce bilayer formation in lysophosphatidylcholine (LPC) systems was investigated as a function of the conformation of the peptide. The conformation was varied by using different solvents to cosolubilize gramicidin and lipid. Using circular dichroism (CD), it was found that when codissolved in trifluoroethanol (TFE), after drying and subsequent hydration, gramicidin is mainly present in the single-stranded beta 6.3-helical configuration, whereas when using chloroform/methanol or ethanol as the solvent, it is proposed that the dominant conformation of gramicidin in the membrane is that of the double-stranded antiparallel dimer. Employing 31P NMR, the stoichiometry for bilayer formation was found to be 6 to 7 lipid molecules per gramicidin monomer, when samples were prepared from TFE, whereas a stoichiometry of 4 was found when chloroform/methanol or ethanol was the solvent. Upon heating the latter samples, a conversion was observed in the CD pattern toward that indicative of the beta 6.3-helical configuration. This change was accompanied by an increase in the extent of bilayer formation. Next, it was investigated whether the conformation of gramicidin and its ability to induce bilayer formation were dependent on the lipid acyl chain length. CD measurements of samples prepared from TFE indicated that gramicidin, independent of acyl chain length, was present in the beta 6.3-helical configuration but the intensity of the ellipticities at 218 nm increased with the length of the acyl chain. The extent of bilayer formation in these samples was found to be largely chain length independent.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J A Killian
- Laboratory of Molecular Biophysics, School of Medicine, University of Alabama, Birmingham 35294
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44
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Killian JA, Nicholson LK, Cross TA. Solid-state 15N-NMR evidence that gramicidin A can adopt two different backbone conformations in dimyristoylphosphatidylcholine model membrane preparations. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 943:535-40. [PMID: 2458135 DOI: 10.1016/0005-2736(88)90387-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Using [15N-Val7]gramicidin A it is shown by solid state 15N-NMR that in dimyristoylphosphatidylcholine model membrane preparations evidence is obtained for two different backbone conformations of gramicidin. One of these conformations is the familiar channel state while a second conformation possesses very different dynamic and structural characteristics. The relative amounts of the conformations depend upon the solvent used to initially codissolve peptide and lipid. Furthermore, by incubation of the samples at modestly elevated temperatures a conversion can be induced from the non-channel to the channel state in a lipid environment.
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Affiliation(s)
- J A Killian
- Department of Chemistry, Florida State University, Tallahassee
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45
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Gasset M, Killian JA, Tournois H, de Kruijff B. Influence of cholesterol on gramicidin-induced HII phase formation in phosphatidylcholine model membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 939:79-88. [PMID: 2450586 DOI: 10.1016/0005-2736(88)90049-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The influence of cholesterol incorporation on gramicidin-induced hexagonal HII phase formation in different phosphatidylcholine model systems was investigated by 31P- and 2H-NMR, small-angle X-ray diffraction and differential scanning calorimetry. In liquid-crystalline distearoylphosphatidylcholine systems cholesterol inhibits gramicidin-induced HII phase formation. In dioleoylphosphatidylcholine the opposite effect is observed. Cholesterol appears to preferentially interact with gramicidin under liquid-crystalline conditions in both systems. Two phenomena that had been reported for gramicidin-treated erythrocyte membranes and derived liposomes (Tournois, H., Leunissen-Bijvelt, J., Haest, C.W.M., De Gier, J. and De Kruijff, B. (1987) Biochemistry, 26, 6613-6621) could also be observed in more simple dioleoylphosphatidylcholine-gramicidin-cholesterol systems. These are (i) an increase in tube diameter in the gramicidin-induced HII phase with increasing temperature, which is ascribed to the presence of cholesterol in this phase, and (ii) the loss of the hexagonal HII phase related 31P-NMR line shape at lower temperatures despite the presence of this phase as demonstrated with X-ray diffraction. This latter phenomenon appears to be due to restrictions in the rate of lateral diffusion of the phospholipids around the HII tubes due to the presence of gramicidin.
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Affiliation(s)
- M Gasset
- Department of Biochemistry, University of Utrecht, The Netherlands
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46
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Aranda FJ, de Kruijff B. Interrelationships between tyrocidine and gramicidin A' in their interaction with phospholipids in model membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 937:195-203. [PMID: 2446665 DOI: 10.1016/0005-2736(88)90241-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
(1) The interaction of tyrocidine with different lipids is studied in model membranes and the results are compared to the gramicinid-lipid interaction. (2) The tyrocidine-dielaidoylphosphatidylethanolamine interaction gives rise to a population of phospholipids with a lower gel to liquid-crystalline transition temperature and to an abolition of the bilayer to HII phase transition, resulting in a macroscopic organization with dynamic and structural properties different from those of the pure lipid. (3) Tyrocidine has a strong fluidizing effect on the acyl chains of phosphatidylcholines, manifested by a decrease in enthalpy of the main thermotropic transition. (4) No evidence of a gramicidin A'-like lipid-structure modulating activity was found. However, tyrocidine inhibits the formation by gramicidin of an HII phase in dioleoylphosphatidylcholine model membranes. Instead, a cubic type of lipid organization is observed. (5) Tyrocidine greatly perturbs the barrier properties of dioleoylphosphatidylcholine model membrane. (6) Gramicidin A' reverses the effect of tyrocidine on membrane permeability by forming a complex in the model membrane with an apparent 1:1 stoichiometry. (7) The results suggest that both peptide antibiotics, which are produced by Bacillus brevis ATC 8185 prior to sporulation, show antagonism in their effect on membrane structure similar to their effect on superhelical DNA (Bogh, A. and Ristow, H. (1986) Eur. J. Biochem. 160, 587-591. The possible underlying basic mechanism is indicated.
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Affiliation(s)
- F J Aranda
- Institute of Molecular Biology and Medical Biotechnology, University of Utrecht, The Netherlands
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47
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Abstract
Gramicidin A forms ion-conducting channels which can traverse the hydrocarbon core of lipid bilayer membranes. The structures formed by gramicidin A are among the best characterized of all membrane-bound polypeptides or proteins. In this review a brief summary is given of the occurrence, conformation, and synthesis of gramicidin A, and of its use as a model for ion transport and the interaction of proteins and lipids in biological membranes.
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Affiliation(s)
- B Cornell
- Commonwealth Scientific and Industrial Research Organization, North Ryde, N.S.W., Australia
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48
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Tournois H, Killian JA, Urry DW, Bokking OR, de Gier J, de Kruijff B. Solvent determined conformation of gramicidin affects the ability of the peptide to induce hexagonal HII phase formation in dioleoylphosphatidylcholine model membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 905:222-6. [PMID: 2445381 DOI: 10.1016/0005-2736(87)90026-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
It is shown by 31P-NMR and small angle X-ray scattering that induction of an hexagonal HII phase in dioleoylphosphatidylcholine model membranes by external addition of gramicidin A' depends on the solvent which is used to solubilize the peptide. Addition of gramicidin from dimethylsulfoxide or trifluoroethanol solution leads to HII phase formation whereas addition of the peptide from ethanol does not. This solvent dependence is shown by circular dichroism to be correlated with the peptide conformation. The channel conformation appears to be responsible for HII phase formation by gramicidin.
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Affiliation(s)
- H Tournois
- Department of Biochemistry, University of Utrecht, The Netherlands
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49
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Brasseur R, Killian JA, De Kruijff B, Ruysschaert JM. Conformational analysis of gramicidin-gramicidin interactions at the air/water interface suggests that gramicidin aggregates into tube-like structures similar as found in the gramicidin-induced hexagonal HII phase. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 903:11-7. [PMID: 2443166 DOI: 10.1016/0005-2736(87)90150-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The energetics of interaction and the type of aggregate structure in lateral assemblies of up to five gramicidin molecules in the beta 6.3 helical conformation at the air/water interface was calculated using conformational analysis procedures. It was found that within the aggregate two types of gramicidin interaction occur. One leading to a linear organization with a mean interaction energy between monomers of -6 kcal/mol and one in a perpendicular direction leading to a circularly organization with a lower mean interaction energy of -10 kcal/mol. Extrapolation towards larger gramicidin assemblies predicts that gramicidin itself could form tubular structures similar to those found in the gramicidin-induced HII phase. The tryptophans appear to play an essential role in the tubular organization of the gramicidin aggregate, since they determine the cone shape of the monomer and contribute to the structure of the monomer and oligomer by stacking interactions. These results, which are discussed in the light of experimental observations of gramicidin self-association in model membranes and the importance of the tryptophans for HII phase formation, further support the view (Killian, J.A. and De Kruijff, B. (1986) Chem. Phys. Lipids 40, 259-284) that gramicidin is a first example of a new class of hydrophobic polypeptides which can form cylindrical structures within the hydrophobic core of the membrane.
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Affiliation(s)
- R Brasseur
- Laboratoire Chimie-Physique des Macromolécules aux Interfaces, Université Libre de Bruxelles, Brussel, Belgium
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50
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Aranda FJ, Killian JA, de Kruijff B. Importance of the tryptophans of gramicidin for its lipid structure modulating activity in lysophosphatidylcholine and phosphatidylethanolamine model membranes. A comparative study employing gramicidin analogs and a synthetic alpha-helical hydrophobic polypeptide. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 901:217-28. [PMID: 2440475 DOI: 10.1016/0005-2736(87)90118-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The importance of the tryptophan residues of gramicidin for the lipid structure modulating activity of this pentadecapeptide was investigated by studying the interaction of gramicidin analogs A, B, C (which have a tryptophan, phenylalanine and tyrosine in position 11, respectively) and tryptophan-N-formylated gramicidin (in which the four tryptophan residues have been formylated) with several phospholipid systems. In addition an alpha-helical model pentadecapeptide (P15) was studied to further test the specificity of the gramicidin-lipid interaction. DSC experiments showed that all the gramicidin analogs produced a significant decrease in the gel to liquid-crystalline transition enthalpy of dipalmitoylphosphatidylcholine. The P15 peptide was much less effective in this respect. In dielaidoylphosphatidylethanolamine the gel----liquid-crystalline transition enthalpy was much less affected by the incorporation of these molecules. In this lipid system tryptophan-N-formylated gramicidin was found to be the most ineffective. 31P-NMR and small angle X-ray diffraction experiments showed that the ability of the peptides to induce bilayer structures in palmitoyllysophosphatidylcholine and HII phase promotion in dielaidoylphosphatidylethanolamine systems follows the order: gramicidin A' (natural mixture) approximately equal to gramicidin A greater than gramicidin B approximately equal to gramicidin C greater than tryptophan-N-formylated gramicidin greater than P15. These results support the hypothesis that the shape of gramicidin and its aggregational behaviour, in which the tryptophan residues play an essential role, are major determinants in the unique lipid structure modulating activity of gramicidin.
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