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Afanasyeva EF, Syryamina VN, De Zotti M, Formaggio F, Toniolo C, Dzuba SA. Peptide antibiotic trichogin in model membranes: Self-association and capture of fatty acids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:524-531. [PMID: 30550880 DOI: 10.1016/j.bbamem.2018.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 10/27/2022]
Abstract
The antimicrobial action of peptides in bacterial membranes is commonly related to their mode of self-assembling which results in pore formation. To optimize peptide antibiotic use for therapeutic purposes, a study on the concentration dependence of self-assembling process is thus desirable. In this work, we investigate this dependence for peptaibol trichogin GA IV (Tric) in the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) model membrane in the range of peptide concentrations between 0.5 and 3.3 mol%. Pulsed double electron-electron resonance (PELDOR) applied on spin-labeled peptide analogs highlights the onset of peptide dimerization above a critical peptide concentration value, namely ~ 2 mol%. Electron spin echo (ESE) envelope modulation (ESEEM) for D2O-hydrated bilayers shows that dimerization is accompanied by peptide re-orientation towards a trans-membrane disposition. For spin-labeled stearic acids (5-DSA) in POPC bilayers, the study of ESE decays and ESEEM in the presence of a deuterated peptide analog indicates that above the critical peptide concentration the 5-DSA molecules are attracted by peptide molecules, forming nanoclusters. As the 5-DSA molecules represent a model for the behavior of fatty acids participating in bacterial membrane homeostasis, such capturing action by Tric may represent an additional mechanism of its antibiotic activity.
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Affiliation(s)
- Ekaterina F Afanasyeva
- Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - Victoria N Syryamina
- Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - Marta De Zotti
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Fernando Formaggio
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy; Institute of Biomolecular Chemistry, Padova Unit, CNR, 35131 Padova, Italy
| | - Claudio Toniolo
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy; Institute of Biomolecular Chemistry, Padova Unit, CNR, 35131 Padova, Italy
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk 630090, Russian Federation.
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Bortolus M, Dalzini A, Maniero AL, Panighel G, Siano A, Toniolo C, De Zotti M, Formaggio F. Insights into peptide-membrane interactions of newly synthesized, nitroxide-containing analogs of the peptaibiotic trichogin GAIV using EPR. Biopolymers 2017; 108. [DOI: 10.1002/bip.22913] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/21/2016] [Accepted: 06/29/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Marco Bortolus
- Department of Chemistry; University of Padova; Padova 35131 Italy
| | - Annalisa Dalzini
- Department of Chemistry; University of Padova; Padova 35131 Italy
| | | | - Giacomo Panighel
- Department of Chemistry; University of Padova; Padova 35131 Italy
| | - Alvaro Siano
- Department of Chemistry; University of Padova; Padova 35131 Italy
- Departamento de Química Orgánica; Facultad de Bioquímica y Ciencias Biológicas (FBCB), Universidad Nacional del Litoral (UNL); 3000 Santa Fe Argentina
| | - Claudio Toniolo
- Department of Chemistry; University of Padova; Padova 35131 Italy
- Institute of Biomolecular Chemistry, Padova Unit, CNR; Padova 35131 Italy
| | - Marta De Zotti
- Department of Chemistry; University of Padova; Padova 35131 Italy
| | - Fernando Formaggio
- Department of Chemistry; University of Padova; Padova 35131 Italy
- Institute of Biomolecular Chemistry, Padova Unit, CNR; Padova 35131 Italy
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3
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Shabestari MH, van Son M, Moretto A, Crisma M, Toniolo C, Huber M. Conformation and EPR characterization of rigid, 310 -helical peptides with TOAC spin labels: Models for short distances. Biopolymers 2016; 102:244-51. [PMID: 24488683 DOI: 10.1002/bip.22467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/21/2014] [Accepted: 01/27/2014] [Indexed: 11/07/2022]
Abstract
For 3D-structure determination in biophysical systems EPR is rapidly gaining ground. Proteins labeled specifically with two nitroxide spin labels can be prepared, and several EPR methods are available for distance determination, which makes it possible to determine distance constraints. However, such methods require frozen solutions, potentially causing non-physiological states of the sample. Here, we target spin- spin interaction in liquid solution at room temperature using rigid model compounds. A series of 310 -helical peptides, based on α-aminoisobutyric acid (Aib), is synthesized with pairs of spin labels separated by three, four, and five amino acids. To avoid flexibility, the noncoded nitroxyl-containing α-amino acid TOAC that is rigidly connected with the peptide backbone, is used. The EPR spectra of the peptides show a decreasing amount of coupling between the two spin labels within this series. We suggest through-bond interaction as the dominating mechanism for exchange interaction (J) and find a stronger J-coupling than in the corresponding Ala-based TOAC-peptides investigated previously (Hanson, et al., J Am Chem Soc 1996, 118, 7618-7625). We speculate that stronger coupling in Aib- vs Ala- peptides is due to intrinsically stronger through-bond interaction in the Aib-based peptides.
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Affiliation(s)
- Maryam Hashemi Shabestari
- Department of Molecular Physics, Huygens Laboratory, Leiden University, 2300, RA Leiden, The Netherlands
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4
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Milov AD, Tsvetkov YD, Raap J, De Zotti M, Formaggio F, Toniolo C. Review conformation, self-aggregation, and membrane interaction of peptaibols as studied by pulsed electron double resonance spectroscopy. Biopolymers 2016; 106:6-24. [DOI: 10.1002/bip.22713] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 07/29/2015] [Accepted: 08/09/2015] [Indexed: 12/15/2022]
Affiliation(s)
- Alexander D. Milov
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk 630090 Russian Federation
| | - Yuri D. Tsvetkov
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion; Novosibirsk 630090 Russian Federation
| | - Jan Raap
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University; 2300 RA Leiden The Netherlands
| | - Marta De Zotti
- Department of Chemistry; University of Padova; Padova 35131 Italy
| | | | - Claudio Toniolo
- Department of Chemistry; University of Padova; Padova 35131 Italy
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5
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Milov AD, Tsvetkov YD, Bortolus M, Maniero AL, Gobbo M, Toniolo C, Formaggio F. Synthesis and conformational properties of a TOAC doubly spin-labeled analog of the medium-length, membrane active peptaibiotic ampullosporin a as revealed by cd, fluorescence, and EPR spectroscopies. Biopolymers 2014; 102:40-8. [DOI: 10.1002/bip.22362] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/10/2013] [Accepted: 07/12/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Alexander D. Milov
- Institute of Chemical Kinetics and Combustion; Novosibirsk 630090 Russian Federation
| | - Yuri D. Tsvetkov
- Institute of Chemical Kinetics and Combustion; Novosibirsk 630090 Russian Federation
| | - Marco Bortolus
- Department of Chemical Sciences; University of Padova; 35131 Padova Italy
| | - Anna Lisa Maniero
- Department of Chemical Sciences; University of Padova; 35131 Padova Italy
| | - Marina Gobbo
- Department of Chemical Sciences; University of Padova; 35131 Padova Italy
- Institute of Biomolecular Chemistry; Padova Unit, CNR 35131 Padova Italy
| | - Claudio Toniolo
- Department of Chemical Sciences; University of Padova; 35131 Padova Italy
- Institute of Biomolecular Chemistry; Padova Unit, CNR 35131 Padova Italy
| | - Fernando Formaggio
- Department of Chemical Sciences; University of Padova; 35131 Padova Italy
- Institute of Biomolecular Chemistry; Padova Unit, CNR 35131 Padova Italy
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Milov AD, Tsvetkov YD, De Zotti M, Prinzivalli C, Biondi B, Formaggio F, Toniolo C, Gobbo M. Aggregation modes of the spin mono-labeled tylopeptin B and heptaibin peptaibiotics in frozen solutions of weak polarity as studied by PELDOR spectroscopy. J STRUCT CHEM+ 2013. [DOI: 10.1134/s0022476613070056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Syryamina VN, De Zotti M, Peggion C, Formaggio F, Toniolo C, Raap J, Dzuba SA. A Molecular View on the Role of Cholesterol upon Membrane Insertion, Aggregation, and Water Accessibility of the Antibiotic Lipopeptide Trichogin GA IV As Revealed by EPR. J Phys Chem B 2012; 116:5653-60. [DOI: 10.1021/jp301660a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Victoria N. Syryamina
- Institute
of Chemical Kinetics
and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Marta De Zotti
- ICB, Padova Unit, CNR, Department
of Chemistry, University of Padova, 35131
Padova, Italy
| | - Cristina Peggion
- ICB, Padova Unit, CNR, Department
of Chemistry, University of Padova, 35131
Padova, Italy
| | - Fernando Formaggio
- ICB, Padova Unit, CNR, Department
of Chemistry, University of Padova, 35131
Padova, Italy
| | - Claudio Toniolo
- ICB, Padova Unit, CNR, Department
of Chemistry, University of Padova, 35131
Padova, Italy
| | - Jan Raap
- Leiden Institute
of Chemistry,
Gorlaeus Laboratories, University of Leiden, 2300 RA Leiden, The Netherlands
| | - Sergei A. Dzuba
- Institute
of Chemical Kinetics
and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russia
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The spin label amino acid TOAC and its uses in studies of peptides: chemical, physicochemical, spectroscopic, and conformational aspects. Biophys Rev 2012; 4:45-66. [PMID: 22347893 PMCID: PMC3271205 DOI: 10.1007/s12551-011-0064-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 12/20/2011] [Indexed: 01/21/2023] Open
Abstract
We review work on the paramagnetic amino acid 2,2,6,6-tetramethyl-N-oxyl-4-amino-4-carboxylic acid, TOAC, and its applications in studies of peptides and peptide synthesis. TOAC was the first spin label probe incorporated in peptides by means of a peptide bond. In view of the rigid character of this cyclic molecule and its attachment to the peptide backbone via a peptide bond, TOAC incorporation has been very useful to analyze backbone dynamics and peptide secondary structure. Many of these studies were performed making use of EPR spectroscopy, but other physical techniques, such as X-ray crystallography, CD, fluorescence, NMR, and FT-IR, have been employed. The use of double-labeled synthetic peptides has allowed the investigation of their secondary structure. A large number of studies have focused on the interaction of peptides, both synthetic and biologically active, with membranes. In the latter case, work has been reported on ligands and fragments of GPCR, host defense peptides, phospholamban, and β-amyloid. EPR studies of macroscopically aligned samples have provided information on the orientation of peptides in membranes. More recent studies have focused on peptide–protein and peptide–nucleic acid interactions. Moreover, TOAC has been shown to be a valuable probe for paramagnetic relaxation enhancement NMR studies of the interaction of labeled peptides with proteins. The growth of the number of TOAC-related publications suggests that this unnatural amino acid will find increasing applications in the future.
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De Zotti M, Biondi B, Peggion C, Formaggio F, Park Y, Hahm KS, Toniolo C. Trichogin GA IV: a versatile template for the synthesis of novel peptaibiotics. Org Biomol Chem 2011; 10:1285-99. [PMID: 22179201 DOI: 10.1039/c1ob06178j] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trichogin GA IV, isolated from the fungus Trichoderma longibrachiatum, is the prototype of lipopeptaibols, the sub-class of short-length peptaibiotics exhibiting membrane-modifying properties. This peptaibol is predominantly folded in a mixed 3(10)-/α- helical conformation with a clear, albeit modest, amphiphilic character, which is likely to be responsible for its capability to perturb bacterial membranes and to induce cell death. In previous papers, we reported on the interesting biological properties of trichogin GA IV, namely its good activity against Gram positive bacteria, in particular methicillin-resistant S. aureus strains, its stability towards proteolytic degradation, and its low hemolytic activity. Aiming at broadening the antimicrobial activity spectrum by increasing the peptide helical amphiphilicity, in this work we synthesized, by solution and solid-phase methodologies, purified and fully characterized a set of trichogin GA IV analogs in which the four Gly residues at positions 2, 5, 6, 9, lying in the poorly hydrophilic face of the helical structure, are substituted by one (position 2, 5, 6 or 9), two (positions 5 and 6), three (positions 2, 5, and 9), and four (positions 2, 5, 6, and 9) Lys residues. The conformational preferences of the Lys-containing analogs were assessed by FT-IR absorption, CD and 2D-NMR techniques in aqueous, organic, and membrane-mimetic environments. Interestingly, it turns out that the presence of charged residues induces a transition of the helical conformation adopted by the peptaibols (from 3(10)- to α-helix) as a function of pH in a reversible process. The role played in the analogs by the markedly increased amphiphilicity was further tested by fluorescence leakage experiments in model membranes, protease resistance, antibacterial and antifungal activities, cytotoxicity, and hemolysis. Taken together, our biological results provide evidence that some of the least substituted among these analogs are good candidates for the development of new membrane-active antimicrobial agents.
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Affiliation(s)
- Marta De Zotti
- ICB, Padova Unit, CNR, Department of Chemistry, University of Padova, 35131, Padova, Italy
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Milov AD, Samoilova MI, Tsvetkov YD, Jost M, Peggion C, Formaggio F, Crisma M, Toniolo C, Handgraaf JW, Raap J. Supramolecular Structure of Self-Assembling Alamethicin Analog Studied by ESR and PELDOR. Chem Biodivers 2007; 4:1275-98. [PMID: 17589866 DOI: 10.1002/cbdv.200790110] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Three analogs of alamethicin F50/5, labelled with the TOAC (='2,2,6,6-tetramethylpiperidin-1-oxyl-4-amino-4-carboxylic acid') spin label at positions 1 (Alm1), 8 (Alm8), and 16 (Alm16), resp., were studied by Electron-Spin-Resonance (ESR) and Pulsed Electron-Electron Double-Resonance (PELDOR) techniques in solvents of different polarity to investigate the self-assembly of amphipathic helical peptides in membrane-mimicking environments. In polar solvents, alamethicin forms homogeneous solutions. In the weakly polar chloroform/toluene 1 : 1 mixture, however, this peptide forms aggregates that are detectable at 293 K by ESR in liquid solution, as well as by PELDOR in frozen, glassy solution at 77 K. In liquid solution, free alamethicin molecules and their aggregates show rotational-mobility correlation times tau(r) of 0.87 and 5.9 ns, resp. Based on these values and analysis of dipole-dipole interactions of the TOAC labels in the aggregates, as determined by PELDOR, the average number N of alamethicin molecules in the aggregates is estimated to be less than nine. A distance-distribution function between spin labels in the supramolecular aggregate was obtained. This function exhibits two maxima: a broad one at a distance of 3.0 nm, and a wide one at a distance of ca. 7 nm. A molecular-dynamics (MD)-based model of the aggregate, consisting of two parallel tetramers, each composed of four molecules arranged in a 'head-to-tail' fashion, is proposed, accounting for the observed distances and their distribution.
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Affiliation(s)
- Alexander D Milov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, Russian Federation
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11
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Milov AD, Erilov DA, Salnikov ES, Tsvetkov YD, Formaggio F, Toniolo C, Raap J. Structure and spatial distribution of the spin-labelled lipopeptide trichogin GA IV in a phospholipid membrane studied by pulsed electron–electron double resonance (PELDOR). Phys Chem Chem Phys 2005; 7:1794-9. [DOI: 10.1039/b418414a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Milov AD, Tsvetkov YD, Formaggio F, Oancea S, Toniolo C, Raap J. Solvent effect on the distance distribution between spin labels in aggregated spin labeled trichogin GA IV dimer peptides as studied by pulsed electron–electron double resonance. Phys Chem Chem Phys 2004. [DOI: 10.1039/b313701e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Milov AD, Tsvetkov YD, Formaggio F, Oancea S, Toniolo C, Raap J. Aggregation of Spin Labeled Trichogin GA IV Dimers: Distance Distribution between Spin Labels in Frozen Solutions by PELDOR Data. J Phys Chem B 2003. [DOI: 10.1021/jp035057x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. D. Milov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Yu. D. Tsvetkov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - F. Formaggio
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - S. Oancea
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - C. Toniolo
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - J. Raap
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation, Institute of Biomolecular Chemistry, CNR, Department of Organic Chemistry, University of Padova, 35131 Padova, Italy, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
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Milov AD, Tsvetkov YD, Formaggio F, Crisma M, Toniolo C, Raap J. Self-assembling and membrane modifying properties of a lipopeptaibol studied by CW-ESR and PELDOR spectroscopies. J Pept Sci 2003; 9:690-700. [PMID: 14664226 DOI: 10.1002/psc.513] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Trichogin GA IV is a short lipopeptaibol antibiotic that is capable of enhancing the transport of small cations through the phospholipid double layer of the membrane. The antibiotic activity of the undecapeptide is thought to be based on either its self-assembling or membrane-modifying property. The chemical equilibrium between self-aggregated and non-aggregated molecular states was studied by CW-ESR spectroscopy using solutions of TOAC nitroxide spin-labelled trichogin analogues in an apolar solvent to mimic the membrane bound state. At room temperature the two different sets of signals observed in the spectrum were attributed to the presence of both monomers and aggregates in the sample. The ESR spectra of the monomeric and aggregated forms were separated and the dependence of the fraction of monomeric peptide molecules on concentration was obtained over the range 5 x 10(-6) to 7 x 10(-4) M. A two-step aggregation mechanism is proposed: dimerization of peptide molecules followed by aggregation of dimers to assemblies of four peptide molecules per aggregate. The equilibrium constants were estimated for both steps. In addition, the lower lifetime limit was determined for dimers and tetramers. It is shown that when the peptide concentration exceeds 10(-5) M. the major part of the peptide molecules in solution has the form of tetrameric aggregates. Independently, the PELDOR technique was used to investigate the concentration dependence of the parameters of the dipole-dipole interaction between spin labels in frozen (77 K] glassy solutions of aggregates of mono-labelled TOAC analogues. The number of molecules in aggregates as well as the frequency and amplitude of PELDOR signal oscillations were found to be concentration independent in the range 5 x 10(-4) to 8 x 10(-3) M. In the frozen glassy solution state, the number of peptide molecules per aggregate was determined to be close to four, which is in agreement with the value obtained for spin-labelled trichogin at room temperature. The present data provide experimental evidence in favour of a self-assembling rather than a membrane-modifying ion conduction mechanism.
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Affiliation(s)
- A D Milov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090 Russian Federation
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Kropacheva TN, Raap J. Ion transport across a phospholipid membrane mediated by the peptide trichogin GA IV. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1567:193-203. [PMID: 12488053 DOI: 10.1016/s0005-2736(02)00616-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trichogin GA IV is a special member of a class of peptaibols that are linear peptide antibiotics of fungal origin, characterised by the presence of a variable number of alpha-aminoisobutyric acid residues, an acyl group at the N-terminus and a 1,2-amino alcohol at the C-terminus. Most of the peptaibols display ion-channel-forming or at least membrane-modifying properties. The 11-residue-long trichogin GA IV is not only one of shortest peptaibols, but it is also unique for its n-octanoyl group instead of the more common found acetyl group at the N-terminus. For the first time we have found that this lipopeptaibol is able to enhance conduction of monovalent cations through membranes of large unilamellar vesicles (LUVs). The influence of the [Leu-OMe]trichogin GA IV analogue (TRI) on ion permeation was studied under a variety of conditions (lipid composition, lipid-to-peptide ratio and a transmembrane potential). Parallel experiments were performed with the 16-residue long, channel-forming peptaibol, zervamicin (ZER). For the two peptides, the permeability between K(+) and Na(+) was found to be different. In addition, the ion diffusion rate dependencies on the peptide concentration are observed to be different. This might indicate that a different number of aggregated molecules are involved in the rate-limiting step, i.e. 3-4 (TRI) and 4-7 (ZER). In the presence of TRI, dissipation of the transmembrane potential, Delta psi, was observed with a rate to be dependent on the magnitude of both initial Delta psi and peptide concentration. Both peptides were activated by a cis-positive but not by cis-negative Delta psi. Under identical conditions the ion-conducting efficiency of zervamicin was 100-200 times higher than that of trichogin. Our results show that, unlike for zervamicin, the membrane-modifying activity of trichogin is not associated with a channel mechanism.
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Affiliation(s)
- T N Kropacheva
- Department of Chemistry, Udmurt State University, Izhevsk, Russia
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