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Syryamina VN, Matveeva AG, Vasiliev YV, Savitsky A, Grishin YA. Improving B 1 field homogeneity in dielectric tube resonators for EPR spectroscopy via controlled shaping of the dielectric insert. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 311:106685. [PMID: 31981782 DOI: 10.1016/j.jmr.2020.106685] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
We propose an approach for improving the homogeneity of microwave magnetic field amplitude in a dielectric tube resonator for electron paramagnetic resonance spectroscopy at X-band. The improvement is achieved by "shaping" (controllable variation of the outer diameter of a dielectric insert along its axial direction). Various shaping scenarios based on the principle of discrete solenoids and electromagnetic calculations have been considered. The dielectric insert having the most promising shape was manufactured from a bismuth germanate single crystal. The shaped insert increases the area at B1 > 0.9 B1max from 5.06 to 7.36 mm. Higher sensitivity and lower likelihood of quantitative errors have been achieved in pulse EPR experiments for "long" samples (whose length was comparable to that of the dielectric insert) in a shaped dielectric insert.
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Affiliation(s)
- Victoria N Syryamina
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya Str., 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova Str., 2, 630090 Novosibirsk, Russia.
| | - Anna G Matveeva
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya Str., 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova Str., 2, 630090 Novosibirsk, Russia
| | - Yan V Vasiliev
- Nikolaev Institute of Inorganic Chemistry, Acad. Lavrentiev Av., 3, 630090 Novosibirsk, Russia
| | - Anton Savitsky
- Physics Department, Technical University of Dortmund, Otto-Hahn-Straße 4a, 44227 Dortmund, Germany
| | - Yuri A Grishin
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya Str., 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova Str., 2, 630090 Novosibirsk, Russia
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2
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De Zotti M, Syryamina VN, Hussain R, Longo E, Siligardi G, Dzuba SA, Stella L, Formaggio F. A Temperature-Driven, Reversible, Helical-Handedness Inversion in Peptaibol Analogues Tuned by the C-Terminal Capping Moiety. Chembiochem 2019; 20:2125-2132. [PMID: 31095838 DOI: 10.1002/cbic.201900235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Indexed: 11/07/2022]
Abstract
Trichogin is a natural peptide endowed with antimicrobial and antitumor activity. A member of the peptaibol family, trichogin possesses a C-terminal amino alcohol. In the past, this moiety was substituted for a methyl ester for synthetic purposes and it was observed that this apparently slight modification caused significant changes in the peptide bioactivity. With the aim of understanding the reasons behind such observations, a detailed spectroscopic study on a number of trichogin analogues has been performed. Herein, data obtained from synchrotron radiation circular dichroism, NMR spectroscopy, and fluorescence spectroscopy in organic solvents at cryogenic temperatures are compared with those independently acquired by means of EPR spectroscopy at 80 K. It is unambiguously revealed that the presence of a reversible, temperature-driven, screw-sense interconversion from a right- to left-handed helix is determined by the C-terminal capping moiety. Data demonstrate, for the first time, the key role of a C-terminal methyl ester in promoting peptide screw-sense inversion.
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Affiliation(s)
- Marta De Zotti
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131, Padova, Italy
| | - Victoria N Syryamina
- Institute of Chemical Kinetics and Combustion, RAS, Ulitsa Institutskaya 3, Novosibirsk, 630090, Russian Federation.,Novosibirsk State University, Ulitsa Pirogova 2, Novosibirsk, 630090, Russian Federation
| | - Rohanah Hussain
- Diamond Light Source Ltd., Harwell Innovation Campus, Chilton, Didcot, Oxfordshire, UK
| | - Edoardo Longo
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100, Bozen-Bolzano, Italy
| | - Giuliano Siligardi
- Diamond Light Source Ltd., Harwell Innovation Campus, Chilton, Didcot, Oxfordshire, UK
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, RAS, Ulitsa Institutskaya 3, Novosibirsk, 630090, Russian Federation.,Novosibirsk State University, Ulitsa Pirogova 2, Novosibirsk, 630090, Russian Federation
| | - Lorenzo Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della ricerca scientifica 1, 00133, Rome, Italy
| | - Fernando Formaggio
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131, Padova, Italy
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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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4
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Syryamina VN, De Zotti M, Toniolo C, Formaggio F, Dzuba SA. Alamethicin self-assembling in lipid membranes: concentration dependence from pulsed EPR of spin labels. Phys Chem Chem Phys 2018; 20:3592-3601. [DOI: 10.1039/c7cp07298h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The antimicrobial action of the peptide antibiotic alamethicin (Alm) is commonly related to peptide self-assembling resulting in the formation of voltage-dependent channels in bacterial membranes, which induces ion permeation.
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Affiliation(s)
- Victoria N. Syryamina
- Institute of Chemical Kinetics and Combustion
- RAS
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
| | - Marta De Zotti
- Department of Chemical Sciences
- University of Padova
- 35131 Padova
- Italy
| | - Claudio Toniolo
- Department of Chemical Sciences
- University of Padova
- 35131 Padova
- Italy
- Institute of Biomolecular Chemistry
| | - Fernando Formaggio
- Department of Chemical Sciences
- University of Padova
- 35131 Padova
- Italy
- Institute of Biomolecular Chemistry
| | - Sergei A. Dzuba
- Institute of Chemical Kinetics and Combustion
- RAS
- Novosibirsk 630090
- Russian Federation
- Novosibirsk State University
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Biondi B, Peggion C, De Zotti M, Pignaffo C, Dalzini A, Bortolus M, Oancea S, Hilma G, Bortolotti A, Stella L, Pedersen JZ, Syryamina VN, Tsvetkov YD, Dzuba SA, Toniolo C, Formaggio F. Conformational properties, membrane interaction, and antibacterial activity of the peptaibiotic chalciporin A: Multitechnique spectroscopic and biophysical investigations on the natural compound and labeled analogs. Biopolymers 2017; 110. [PMID: 29127716 DOI: 10.1002/bip.23083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/06/2017] [Accepted: 10/15/2017] [Indexed: 02/28/2024]
Abstract
In this work, an extensive set of spectroscopic and biophysical techniques (including FT-IR absorption, CD, 2D-NMR, fluorescence, and CW/PELDOR EPR) was used to study the conformational preferences, membrane interaction, and bioactivity properties of the naturally occurring synthetic 14-mer peptaibiotic chalciporin A, characterized by a relatively low (≈20%), uncommon proportion of the strongly helicogenic Aib residue. In addition to the unlabeled peptide, we gained in-depth information from the study of two labeled analogs, characterized by one or two residues of the helicogenic, nitroxyl radical-containing TOAC. All three compounds were prepared using the SPPS methodology, which was carefully modified in the course of the syntheses of TOAC-labeled analogs in view of the poorly reactive α-amino function of this very bulky residue and the specific requirements of its free-radical side chain. Despite its potentially high flexibility, our results point to a predominant, partly amphiphilic, α-helical conformation for this peptaibiotic. Therefore, not surprisingly, we found an effective membrane affinity and a remarkable penetration propensity. However, chalciporin A exhibits a selectivity in its antibacterial activity not in agreement with that typical of the other members of this peptide class.
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Affiliation(s)
- Barbara Biondi
- Institute of Biomolecular, Chemistry, Padova Unit, CNR, Padova, 35131, Italy
| | - Cristina Peggion
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
| | - Marta De Zotti
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
| | - Chiara Pignaffo
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
| | - Annalisa Dalzini
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
| | - Marco Bortolus
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
| | - Simona Oancea
- Department of Agricultural Sciences and Food Engineering, "Lucian Blaga" University of Sibiu, Sibiu, 550012, Romania
| | - Geta Hilma
- Department of Medicine, "Lucian Blaga" University of Sibiu, Sibiu, 550012, Romania
| | - Annalisa Bortolotti
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, 00133, Italy
| | - Lorenzo Stella
- Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, Rome, 00133, Italy
| | - Jens Z Pedersen
- Department of Biology, University of Rome Tor Vergata, Rome, 00133, Italy
| | - Victoria N Syryamina
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090, Russian Federation
| | - Yuri D Tsvetkov
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090, Russian Federation
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Novosibirsk, 630090, Russian Federation
| | - Claudio Toniolo
- Institute of Biomolecular, Chemistry, Padova Unit, CNR, Padova, 35131, Italy
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
| | - Fernando Formaggio
- Institute of Biomolecular, Chemistry, Padova Unit, CNR, Padova, 35131, Italy
- Department of Chemical Sciences, University of Padova, Padova, 35131, Italy
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6
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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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