39 results on '"Yuichi Umegawa"'
Search Results
2. LnDOTA ‐d 8 , a versatile chemical‐shift thermometer for 2 H solid‐state NMR
- Author
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Yuichi Umegawa, Takeshi Shimonishi, Hiroshi Tsuchikawa, and Michio Murata
- Subjects
General Materials Science ,General Chemistry - Published
- 2022
3. Depth-Dependent Segmental Melting of the Sphingomyelin Alkyl Chain in Lipid Bilayers
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Hiroshi Tsuchikawa, Mami Monji, Yuichi Umegawa, Tomokazu Yasuda, J. Peter Slotte, and Michio Murata
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Membrane Microdomains ,Calorimetry, Differential Scanning ,Lipid Bilayers ,Phosphatidylcholines ,Temperature ,Electrochemistry ,General Materials Science ,Surfaces and Interfaces ,Deuterium ,Condensed Matter Physics ,Spectroscopy ,Sphingomyelins - Abstract
The chain melting of lipid bilayers has often been investigated in detail using calorimetric methods, such as differential scanning calorimetry (DSC), and the resultant main transition temperature is regarded as one of the most important parameters in model membrane experiments. However, it is not always clear whether the hydrocarbon chains of lipids are gradually melting along the depth of the lipid bilayer or whether they all melt concurrently in a very narrow temperature range, as implied by DSC. In this study, we focused on stearoyl-d-sphingomyelin (SSM) as an example of raft-forming lipids. We synthesized deuterium-labeled SSMs at the 4', 10', and 16' positions, and their depth-dependent melting was measured using solid-state deuterium NMR by changing the temperature by 1.0 °C, and comparing with that observed from a saturated lipid, palmitoylstearoylphosphatidylcholine (PSPC). The results showed that SSM exhibited a characteristic depth-dependent melting, which was not observed for PSPC. The strong intermolecular hydrogen bonds between the sphingomyelin amide moiety probably caused the chain melting to start from the chain terminus through the middle part and end in the upper part. This depth-dependent melting implies that the small gel-like domains of SSM remain at temperatures slightly above the main transition temperature. These sphingomyelin features may be responsible for the biological properties of SM-based lipid rafts.
- Published
- 2022
4. Lipid chain-driven interaction of a lipidated Src-family kinase Lyn with the bilayer membrane
- Author
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Shinya Hanashima, Kanako Mito, Yuichi Umegawa, Michio Murata, and Hironobu Hojo
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src-Family Kinases ,Cell Membrane ,Lipid Bilayers ,Organic Chemistry ,Physical and Theoretical Chemistry ,Peptides ,Biochemistry ,Phospholipids - Abstract
S-Palmitoyl and N-myristoyl chains of Lyn cooperatively facilitate binding to the anionic lipids in membranes by extending the hydrocarbon chains deeper into the membrane interior.
- Published
- 2022
5. Author response for 'LnDOTA ‐d 8 , a versatile chemical‐shift thermometer for 2 H solid‐state NMR'
- Author
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null Yuichi Umegawa, null Tsuyoshi Shimonishi, null Hiroshi Tsuchikawa, and null Michio Murata
- Published
- 2022
6. LnDOTA-d
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Yuichi, Umegawa, Takeshi, Shimonishi, Hiroshi, Tsuchikawa, and Michio, Murata
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Membrane Lipids ,Magnetic Resonance Spectroscopy ,Thermometers ,Lipid Bilayers ,Temperature ,Ligands - Published
- 2022
7. Effect of the number of sugar units on the interaction between diosgenyl saponin and membrane lipids
- Author
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Joan Candice Ondevilla, Shinya Hanashima, Akane Mukogawa, Darcy Garza Miyazato, Yuichi Umegawa, and Michio Murata
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Biophysics ,Cell Biology ,Biochemistry - Published
- 2023
8. Amphotericin B assembles into seven-molecule ion channels: An NMR and molecular dynamics study
- Author
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Michio Murata, Hiroshi Tsuchikawa, Shinya Hanashima, Tohru Oishi, Sangjae Seo, Tomoya Yamamoto, Kosuke Funahashi, Taiga Suzuki, Shigeru Matsuoka, Nobuaki Matsumori, Mayank Kumar Dixit, Yuichi Umegawa, Yasuo Nakagawa, and Wataru Shinoda
- Subjects
Ergosterol ,chemistry.chemical_compound ,Molecular dynamics ,Membrane ,Multidisciplinary ,Solid-state nuclear magnetic resonance ,Chemistry ,Antifungal drug ,Biophysics ,Molecule ,Nuclear magnetic resonance spectroscopy ,Ion channel - Abstract
Amphotericin B, an antifungal drug with a long history of use, forms fungicidal ion-permeable channels across cell membranes. Using solid-state nuclear magnetic resonance spectroscopy and molecular dynamics simulations, we experimentally elucidated the three-dimensional structure of the molecular assemblies formed by this drug in membranes in the presence of fungal sterol, ergosterol. A stable assembly consisting of seven drug molecules was observed to form an ion conductive channel. The structure is somewhat similar to the upper half of the barrel-stave model proposed in the 1970s but substantially different in the number of molecules and in their arrangement. The high-resolution structure explains many previous findings, including structure-activity relationships of the drug, which will be useful for improving drug efficacy and reducing adverse effects.
- Published
- 2022
9. Combined effect of the head groups and alkyl chains of archaea lipids when interacting with bacteriorhodopsin
- Author
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Yuichi Umegawa, Satoshi Kawatake, Michio Murata, and Shigeru Matsuoka
- Subjects
Organic Chemistry ,Biophysics ,Biochemistry - Published
- 2023
10. The Amphotericin B–Ergosterol Complex Spans a Lipid Bilayer as a Single-Length Assembly
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Wataru Shinoda, Sangjae Seo, Kosuke Funahashi, Shinya Hanashima, Nobuaki Matsumori, Yuichi Umegawa, Tomoya Yamamoto, Hiroshi Tsuchikawa, and Michio Murata
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Ergosterol ,Magnetic Resonance Spectroscopy ,Lipid Bilayers ,Antifungal drug ,bacterial infections and mycoses ,Polyene ,Biochemistry ,Sterol ,chemistry.chemical_compound ,Membrane ,chemistry ,Amphotericin B ,polycyclic compounds ,medicine ,lipids (amino acids, peptides, and proteins) ,Lipid bilayer ,Erg ,medicine.drug - Abstract
Amphotericin B (AmB) is a polyene macrolide antibiotic clinically used as an antifungal drug. Its preferential complexation with ergosterol (Erg), the major sterol of fungal membranes, leads to the formation of a barrel-stave-like ion channel across a lipid bilayer. To gain a better understanding of the mechanism of action, the mode of lipid bilayer spanning provides essential information. However, because of the lack of methodologies to observe it directly, it has not been revealed for the Erg-containing channel assembly for many years. In this study, we disclosed that the AmB-Erg complex spans a lipid bilayer with a single-molecule length, using solid-state nuclear magnetic resonance (NMR) experiments. Paramagnetic relaxation enhancement by Mn
- Published
- 2019
11. Average Conformation of Branched Chain Lipid PGP-Me That Accounts for the Thermal Stability and High-Salinity Resistance of Archaeal Membranes
- Author
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Wataru Shinoda, Hiroshi Tsuchikawa, Yusuke Miyazaki, Yuichi Umegawa, Michio Murata, Masaki Yamagami, Sangjae Seo, and Jin Cui
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Salinity ,0303 health sciences ,Hot Temperature ,Magnetic Resonance Spectroscopy ,Chemistry ,Membrane lipids ,Bilayer ,030302 biochemistry & molecular biology ,Molecular Dynamics Simulation ,Archaea ,Biochemistry ,03 medical and health sciences ,Crystallography ,Molecular dynamics ,Membrane ,Purple Membrane ,Chain (algebraic topology) ,Membrane protein ,polycyclic compounds ,lipids (amino acids, peptides, and proteins) ,Thermal stability ,Lipid bilayer ,Phospholipids - Abstract
The average conformation of the methyl-branched chains of archaeal lipid phosphatidyl glycerophosphate methyl ester (PGP-Me) was examined in a hydrated bilayer membrane based on the 2H nuclear magnetic resonance (NMR) of enantioselectively 2H-labeled compounds that were totally synthesized for the first time in this study. The NMR results in combination with molecular dynamics simulations revealed that the PGP-Me chain appeared to exhibit behavior different from that of typical membrane lipids such as dimyristoylphosphatidylcholine (DMPC). The C-C bonds of the PGP-Me chain adopt alternative parallel and tilted orientations to the membrane normal as opposed to a DMPC chain where all of the C-C bonds tilt in the same way on average. This characteristic orientation causes the intertwining of PGP-Me chains, which plays an important role in the excellent thermal and high-salinity stabilities of archaeal lipid bilayers and membrane proteins.
- Published
- 2019
12. Small structural alterations greatly influence the membrane affinity of lipophilic ligands: Membrane interactions of bafilomycin A1 and its desmethyl derivative bearing 19F-labeling
- Author
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Tatsuru Hayashi, Yuichi Umegawa, Michio Murata, and Hiroshi Tsuchikawa
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biology ,010405 organic chemistry ,Chemistry ,Bilayer ,ATPase ,Organic Chemistry ,Clinical Biochemistry ,Pharmaceutical Science ,Bafilomycin ,Biological activity ,Desmethyl ,Inhibitory postsynaptic potential ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,chemistry.chemical_compound ,Membrane ,Solid-state nuclear magnetic resonance ,Drug Discovery ,biology.protein ,Biophysics ,Molecular Medicine ,Molecular Biology - Abstract
Molecular behavior under bilayer membrane environments is one of the important research topics concerning how organic molecules exert their biological activities when interacting with cellular membranes. However, chemistry-based approaches to this property have not been successful when compared with the structural biological strategy on ligand-receptor interactions. Here, we investigated the molecular behavior of the lipophilic ATPase inhibitor bafilomycin A1 and its derivatives under a lipid environment from a chemical point of view. Our results revealed significant differences in membrane affinity and dynamics among ligands having different inhibitory potencies, suggesting the specific contribution of ligand-membrane interactions to their biological activity.
- Published
- 2019
13. A Synthetic Approach to the Channel Complex Structure of Antibiotic in a Membrane: Backbone 19F-Labeled Amphotericin B for Solid-State NMR Analysis
- Author
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Tohru Oishi, Yuichi Umegawa, Michio Murata, and Hiroshi Tsuchikawa
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Membrane ,Channel complex ,Solid-state nuclear magnetic resonance ,medicine.drug_class ,Chemistry ,Amphotericin B ,Organic Chemistry ,Antibiotics ,medicine ,Combinatorial chemistry ,medicine.drug - Published
- 2018
14. Conformation and Orientation of Branched Acyl Chains Responsible for the Physical Stability of Diphytanoylphosphatidylcholine
- Author
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Yuichi Umegawa, Wataru Shinoda, Takuya Ono, Hiroshi Tsuchikawa, Michio Murata, and Masaki Yamagami
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Chemistry ,Stereochemistry ,Acylation ,Lipid Bilayers ,Phospholipid ,Molecular Conformation ,Water ,Orientation (graph theory) ,Molecular Dynamics Simulation ,Biochemistry ,Archaea ,Permeability ,chemistry.chemical_compound ,Glycerol ,Phosphatidylcholines ,Moiety ,lipids (amino acids, peptides, and proteins) ,Physical stability - Abstract
Diphytanoylphosphatidylcholine (DPhPC) is a synthetic phospholipid in which two methyl-branched acyl chains are introduced into the glycerol moiety, mimicking phospholipids of eukaryotic and eubacterial origins. The lipid bilayers of DPhPC reproduce the outstanding physical properties of methyl-branched lipids that occur in archaeal membranes. DPhPC is commonly used as the base lipid in biophysical experiments, particularly for recording ion-channel currents. However, the dynamics of lipid molecules that induces their useful physical properties is still unclear. In this study, we examined the conformation and orientation of the methyl-branched acyl chain of DPhPC in a membrane using
- Published
- 2020
15. The Perpendicular Orientation of Amphotericin B Methyl Ester in Hydrated Lipid Bilayers Supports the Barrel-Stave Model
- Author
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Michio Murata, Taiga Suzuki, Nobuaki Matsumori, Tomoya Yamamoto, Shinya Hanashima, Masaki Yamagami, Hiroshi Tsuchikawa, and Yuichi Umegawa
- Subjects
Models, Molecular ,Antifungal Agents ,Magnetic Resonance Spectroscopy ,Lipid Bilayers ,Phospholipid ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Amphotericin B ,Ergosterol ,Molecule ,Lipid bilayer ,Phospholipids ,0303 health sciences ,Liposome ,Molecular Structure ,Chemistry ,030302 biochemistry & molecular biology ,Cell Membrane ,Fungi ,Sterol ,Crystallography ,Sterols ,Membrane ,Models, Chemical ,Isotope Labeling ,Quadrupole ,Liposomes ,Magnetic dipole–dipole interaction - Abstract
The clinically important antibiotic amphotericin B (AmB) is a membrane-active natural product that targets membrane sterol. The antimicrobial activity of AmB is generally attributed to its membrane permeabilization, which occurs when a pore is formed across a lipid bilayer. In this study, the molecular orientation of AmB was investigated using solid-state nuclear magnetic resonance (NMR) to better understand the mechanism of antifungal activity. The methyl ester of AmB (AME) labeled with NMR isotopes, d3-AME, and its fluorinated and/or 13C-labeled derivatives were prepared. All of the AmB derivatives showed similar membrane-disrupting activities and ultraviolet spectra in phospholipid liposomes, suggesting that their molecular assemblies in membranes closely mimic those of AmB. Solid-state 2H NMR measurements of d3-AME in a hydrated membrane showed that the mobility of AME molecules depends on concentration and temperature. At a 1:5:45 AME:Erg:dimyristoylphosphatidylcholine ratio, AME became sufficiently mobilized to observe the motional averaging of quadrupole coupling. On the basis of the rotational averaging effect of 19F chemical shift anisotropy, 2H quadrupolar splitting, and 13C-19F dipolar coupling of 14β-F-AMEs, we deduced that the molecular axis of AME is predominantly parallel to the normal of a lipid bilayer. This result supports the barrel-stave model as a molecular assembly of AmB in membranes.
- Published
- 2019
16. Small structural alterations greatly influence the membrane affinity of lipophilic ligands: Membrane interactions of bafilomycin A
- Author
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Tatsuru, Hayashi, Hiroshi, Tsuchikawa, Yuichi, Umegawa, and Michio, Murata
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Kinetics ,Cell Membrane Permeability ,Magnetic Resonance Spectroscopy ,Cell Membrane ,Hydrogen Bonding ,Fluorine ,Macrolides ,Ligands - Abstract
Molecular behavior under bilayer membrane environments is one of the important research topics concerning how organic molecules exert their biological activities when interacting with cellular membranes. However, chemistry-based approaches to this property have not been successful when compared with the structural biological strategy on ligand-receptor interactions. Here, we investigated the molecular behavior of the lipophilic ATPase inhibitor bafilomycin A
- Published
- 2019
17. Cholesterol-Induced Conformational Change in the Sphingomyelin Headgroup
- Author
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Sangjae Seo, Shinya Hanashima, Kazuhiro Murakami, Michihiro Yura, Yuichi Umegawa, Hiroshi Tsuchikawa, Yo Yano, Nobuaki Matsumori, Wataru Shinoda, and Michio Murata
- Subjects
Conformational change ,Magnetic Resonance Spectroscopy ,Biophysics ,Molecular Conformation ,Molecular Dynamics Simulation ,Choline ,03 medical and health sciences ,chemistry.chemical_compound ,Molecular dynamics ,0302 clinical medicine ,Moiety ,Conformational isomerism ,030304 developmental biology ,Phosphocholine ,Probability ,0303 health sciences ,Diastereomer ,Temperature ,Nuclear magnetic resonance spectroscopy ,Articles ,Deuterium ,Sphingomyelins ,Crystallography ,Cholesterol ,chemistry ,lipids (amino acids, peptides, and proteins) ,Sphingomyelin ,030217 neurology & neurosurgery ,Stearic Acids - Abstract
Sphingomyelin (SM) and cholesterol (Cho) are the important lipids for the formation of biologically functional membrane domains, lipid rafts. However, the interaction between Cho and the headgroup of SM remains unclear. In this study, we performed solid-state NMR experiments to reveal the Cho effects on the headgroup conformation using (2)H-labeled stearoyl-SM (SSM). Deuterated SSMs at the Cα, Cβ, and Cγ positions of a choline moiety were separately prepared and subjected to NMR measurements to determine the quadrupolar splitting of (2)H signals in hydrated SSM unitary and SSM/Cho (1:1) bilayers. Using (2)H NMR and (13)C-(31)P REDOR data, the conformation and orientation of the choline moiety were deduced and compared with those derived from molecular dynamics simulations. In SSM unitary bilayers, three torsional angles in the phosphocholine moiety, P-O-Cα-Cβ, were found to be consecutive +gauche(g)/+g/+g or −g/−g/−g. The orientation and conformation of the SSM headgroup were consistent with the results of our molecular dynamics simulations and the previous results on phosphatidylcholines. The quadrupolar coupling at the α methylene group slightly increased in the presence of Cho, and those at the Cβ and Cγ decreased more significantly, thus suggesting that Cho reduced the gauche conformation at the Cα-Cβ torsion. The conformational ensemble in the presence of Cho may enhance the so-called umbrella effect of the SSM headgroup, resulting in the stabilization of Cho near the SM molecules by concealing the hydrophobic Cho core from interfacial water. We also examined the effect of the chiral centers at the sphingosine chain to the headgroup conformation by determining the enantiomeric excess between the diastereomeric +g/+g/+g and −g/−g/−g conformers using (S)-Cα-deuterated and (R)-Cα-deuterated SSMs. Their (2)H NMR measurements showed that the chiral centers induced the slight diastereomeric excess in the SM headgroup conformation.
- Published
- 2018
18. Diosgenin-induced physicochemical effects on phospholipid bilayers in comparison with cholesterol
- Author
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Michio Murata, Akane Mukogawa, Joan Candice Ondevilla, Shinya Hanashima, and Yuichi Umegawa
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Deuterium NMR ,endocrine system ,Magnetic Resonance Spectroscopy ,Lipid Bilayers ,Clinical Biochemistry ,Phospholipid ,Pharmaceutical Science ,Diosgenin ,01 natural sciences ,Biochemistry ,chemistry.chemical_compound ,Drug Discovery ,Lipid bilayer ,Molecular Biology ,POPC ,Phospholipids ,Calorimetry, Differential Scanning ,Molecular Structure ,Chemistry, Physical ,Dioscorea ,010405 organic chemistry ,Organic Chemistry ,Biological membrane ,Sterol ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,Cholesterol ,Membrane ,chemistry ,Biophysics ,Thermodynamics ,Molecular Medicine ,lipids (amino acids, peptides, and proteins) ,Laurdan - Abstract
Diosgenin (DGN), which is a sterol occurring in plants of the Dioscorea family, has attracted increasing attention for its various pharmacological activities. DGN has a structural similarity to cholesterol (Cho). In this study we investigated the effects of the common tetracyclic cores and the different side chains on the physicochemical properties of lipid bilayer membranes. Differential scanning calorimetry showed that DGN and Cho reduce the phase transition enthalpy to a similar extent. In 2H NMR, deuterated-DGN/Cho and POPC showed similar ordering in POPC bilayers, which revealed that DGN is oriented parallel to the membrane normal like Cho. It was suggested that the affinity of DGN-Cho in membrane is stronger than that of DGN-DGN or Cho-Cho interaction. 31P NMR of POPC in bilayers revealed that, unlike Cho, DGN altered the interactions of POPC headgroups at 30 mol%. These results suggest that DGN below 30 mol% has similar effects with Cho on basic biomembrane properties.
- Published
- 2021
19. Recent Solid-State NMR Studies of Hydrated Lipid Membranes
- Author
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Michio Murata, Nobuaki Matsumori, and Yuichi Umegawa
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0301 basic medicine ,Physics ,030102 biochemistry & molecular biology ,Membrane lipids ,Biological membrane ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,03 medical and health sciences ,Membrane ,Structural biology ,Membrane protein ,Biophysics ,lipids (amino acids, peptides, and proteins) ,Lipid bilayer ,Sphingomyelin ,Lipid raft - Abstract
Interactional and structural analyses of lipids in hydrated biomembranes are at the frontier of membrane physics and biology. Recently, solid-state NMR has emerged as a frequently used technique for the investigation of biomembrane systems, leading to particularly remarkable advances in the study of the structural biology of membrane proteins. However, conformational and interactional analyses of lipid molecules and membrane-active small compounds remain challenging. This chapter highlights recent applications of solid-state NMR to membrane lipids and nonpeptidic molecules such as membrane-active natural products. Lipid rafts are microdomains in cellular membranes formed by sphingomyelin and cholesterol and are thought to constitute a platform for signal transduction. Amphotericin B, theonellamide-A, and amphidinol 3 exert their activities by interacting with lipid membranes. Deuterium quadrupole coupling combined with dipole–dipole interactions has been used to evaluate the interaction modes and dynamic properties of membrane lipids and small membrane-active compounds. Herein, we review the recent advances in these topics using our recent research studies as examples of solid-state NMR investigations of hydrated lipid bilayers.
- Published
- 2018
20. 13C-TmDOTA as versatile thermometer compound for solid-state NMR of hydrated lipid bilayer membranes
- Author
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Matsumori Nobuaki, Michio Murata, Yuichi Umegawa, and Yuya Tanaka
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Chemistry ,Resolution (electron density) ,Analytical chemistry ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Temperature measurement ,030218 nuclear medicine & medical imaging ,0104 chemical sciences ,NMR spectra database ,03 medical and health sciences ,0302 clinical medicine ,Membrane ,Solid-state nuclear magnetic resonance ,Thermometer ,Magic angle spinning ,General Materials Science ,Lipid bilayer - Abstract
Recent advances in solid-state nuclear magnetic resonance (NMR) techniques, such as magic angle spinning and high-power decoupling, have dramatically increased the sensitivity and resolution of NMR. However, these NMR techniques generate extra heat, causing a temperature difference between the sample in the rotor and the variable temperature gas. This extra heating is a particularly crucial problem for hydrated lipid membrane samples. Thus, to develop an NMR thermometer that is suitable for hydrated lipid samples, thulium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (TmDOTA) was synthesized and labeled with (13) C (i.e., (13) C-TmDOTA) to increase the NMR sensitivity. The complex was mixed with a hydrated lipid membrane, and the system was subjected to solid-state NMR and differential scanning calorimetric analyses. The physical properties of the lipid bilayer and the quality of the NMR spectra of the membrane were negligibly affected by the presence of (13) C-TmDOTA, and the (13) C chemical shift of the complex exhibited a large-temperature dependence. The results demonstrated that (13) C-TmDOTA could be successfully used as a thermometer to accurately monitor temperature changes induced by (1) H decoupling pulses and/or by magic angle spinning and the temperature distribution of the sample inside the rotor. Thus, (13) C-TmDOTA was shown to be a versatile thermometer for hydrated lipid assemblies. Copyright © 2015 John Wiley & Sons, Ltd.
- Published
- 2015
21. Role of polyol moiety of amphotericin B in ion channel formation and sterol selectivity in bilayer membrane
- Author
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Michio Murata, Nobuaki Matsumori, Patrick Caffrey, Resul Haser, Hiroshi Tsuchikawa, Yuichi Umegawa, Tomoya Yamamoto, Bernard J. Rawlings, and Shinya Hanashima
- Subjects
Models, Molecular ,Ketone ,Polymers ,Stereochemistry ,Lipid Bilayers ,Clinical Biochemistry ,Pharmaceutical Science ,Biochemistry ,Ion Channels ,chemistry.chemical_compound ,Polyol ,Amphotericin B ,Drug Discovery ,Humans ,Moiety ,Molecular Biology ,chemistry.chemical_classification ,Liposome ,Bilayer ,Organic Chemistry ,technology, industry, and agriculture ,bacterial infections and mycoses ,Polyene ,Sterol ,Sterols ,chemistry ,Liposomes ,Molecular Medicine ,Macrolides ,Selectivity - Abstract
Amphotericin B (AmB) is a polyene macrolide antibiotic widely used to treat mycotic infections. In this paper, we focus on the role of the polyol moiety of AmB in sterol selectivity using 7-oxo-AmB, 7α-OH-AmB, and 7β-OH-AmB. The 7-OH analogs were prepared from 7-oxo-AmB. Their K + flux activity in liposomes showed that introduction of an additional ketone or hydroxy group on the polyol moiety reduces the original activity. Conformational analyses of these derivatives indicated that intramolecular hydrogen-bonding network possibly influenced the conformational rigidity of the macrolactone ring, and stabilized the active conformation in the membrane. Additionally, the flexible polyol leads to destabilization of the whole macrolactone ring conformation, resulting in a loss of sterol selectivity.
- Published
- 2015
22. Centerband-only analysis of rotor-unsynchronized spin echo for measurement of lipid31P chemical shift anisotropy
- Author
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Toshiyuki Yamaguchi, Shigeru Matsuoka, Yuichi Umegawa, and Michio Murata
- Subjects
Chemistry ,Biological membrane ,General Chemistry ,Membrane ,Nuclear magnetic resonance ,Solid-state nuclear magnetic resonance ,Polymorphism (biophysics) ,Spin echo ,Curve fitting ,Magic angle spinning ,lipids (amino acids, peptides, and proteins) ,General Materials Science ,Anisotropy ,Biological system - Abstract
Structural diversity and molecular flexibility of phospholipids are essential for biological membranes to play key roles in numerous cellular processes. Uncovering the behavior of individual lipids in membrane dynamics is crucial for understanding the molecular mechanisms underlying biological functions of cell membranes. In this paper, we introduce a simple method to investigate dynamics of lipid molecules in multi-component systems by measuring the (31) P chemical shift anisotropy (CSA) under magic angle spinning (MAS) conditions. For achieving both signal separation and CSA determination, we utilized a centerband-only analysis of rotor-unsynchronized spin echo (COARSE). This analysis is based on the curve fitting of periodic modulation of centerband intensity along the interpulse delay time in rotor-unsynchronized spin-echo experiments. The utility of COARSE was examined by using phospholipid vesicles, a three-component lipid raft model system, and archaeal purple membranes. We found that the apparent advantages of this method are high resolution and high sensitivity given by the moderate MAS speed and the one-dimensional acquisition with short spin-echo delays. COARSE provides an alternative method for CSA measurement that is effective in the investigation of lipid polymorphologies.
- Published
- 2015
23. Axial Hydrogen at C7 Position and Bumpy Tetracyclic Core Markedly Reduce Sterol’s Affinity to Amphotericin B in Membrane
- Author
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Naohiro Matsushita, Yasuo Nakagawa, Ken'ichi Nonomura, Shinya Hanashima, Nobuaki Matsumori, Michio Murata, Tetsuro Takano, Yuichi Umegawa, Tohru Oishi, and Hiroshi Tsuchikawa
- Subjects
Models, Molecular ,Antifungal Agents ,Double bond ,Stereochemistry ,medicine.medical_treatment ,Molecular Conformation ,Antifungal drug ,Biochemistry ,Steroid ,chemistry.chemical_compound ,Alicyclic compound ,Amphotericin B ,polycyclic compounds ,medicine ,Humans ,chemistry.chemical_classification ,Ergosterol ,Cholesterol ,Cell Membrane ,Fungi ,technology, industry, and agriculture ,bacterial infections and mycoses ,Sterol ,Sterols ,Membrane ,Mycoses ,chemistry ,Liposomes ,lipids (amino acids, peptides, and proteins) - Abstract
The interaction of amphotericin B (AmB) with fungal ergosterol (Erg) is stronger than its interaction with mammalian cholesterol (Cho), and this property of AmB as an antifungal drug is thought to be responsible for its selective toxicity toward fungi. However, the mechanism by which AmB recognizes the structural differences between sterols, particularly minor difference in the sterol alicyclic portion, is largely unknown. Thus, to investigate the mode of interaction between AmB and the sterol core, we assessed the affinity of AmB to various sterols with different alicyclic structures. Ion flux assays and UV spectral measurements clearly revealed the importance of the Δ7-double bond of the sterol B-ring for interaction with the drug. AmB showed lower affinity for triene sterols, which have double bonds at the Δ5, Δ7, and Δ9 positions. Intermolecular distance measurements by (13)C{(19)F} rotational echo double resonance (REDOR) revealed that the AmB macrolide ring is in closer contact with the steroid core of Erg than it is with the Cho core in the membrane. Conformational analysis suggested that an axial hydrogen atom at C7 of Δ5-sterol (2, 6) and the protruded A-ring of Δ5,7,9-sterol (4, 8) sterically hampered face-to-face contact between the van der Waals surface of the sterol core and the macrolide of AmB. These results further suggest that the α-face of sterol alicycle interacts with the flat macrolide structure of AmB.
- Published
- 2015
24. Effect of Sterol Side Chain on Ion Channel Formation by Amphotericin B in Lipid Bilayers
- Author
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Nobuaki Matsumori, Michio Murata, Yasuo Nakagawa, Tetsuro Takano, Yuichi Umegawa, and Hiroshi Tsuchikawa
- Subjects
chemistry.chemical_classification ,Ergosterol ,Antifungal Agents ,genetic structures ,Double bond ,Chemistry ,Stereochemistry ,Lipid Bilayers ,technology, industry, and agriculture ,bacterial infections and mycoses ,Biochemistry ,eye diseases ,Sterol ,chemistry.chemical_compound ,Membrane ,Amphotericin B ,Potassium ,Side chain ,sense organs ,Lipid bilayer ,Erg ,Ion channel - Abstract
Amphotericin B (AmB) is one of the most efficient antimycotic drugs used in clinical practice. AmB interacts with membrane sterols increasing permeability of fungal membranes; however, it is still unclear how AmB selectively recognizes the fungal sterol, ergosterol (Erg), over other sterols in cell membranes. In this study, we investigated the effect of an Erg side chain on AmB activity by testing a series of Erg analogues that shared the same alicyclic structure as Erg but varied in the side chain structure by using the K(+) influx assay. The results clearly showed that the sterol side chain is essential for AmB selectivity toward Erg and for the activity of AmB-sterol ion channels. In agreement with our previous findings showing the direct interaction between the drug and Erg, these data suggested that AmB directly recognizes the sterol side chain structure, consequently promoting the formation of ion channels by AmB. Furthermore, the C24 methyl group and Δ22 double bond in the side chain of Erg are equally important for the interaction with AmB. Conformational analysis revealed that the C24 methyl group contributes to the interaction by increasing the van der Waals (VDW) contact area of the side chain, while the Δ22 double bond restricts the side chain conformation to maximize the VDW contact with the rigid AmB aglycone. This study provides direct experimental evidence of the mechanism of AmB selectivity toward fungal Erg.
- Published
- 2014
25. The Structure of the Bimolecular Complex between Amphotericin B and Ergosterol in Membranes Is Stabilized by Face-to-Face van der Waals Interaction with Their Rigid Cyclic Cores
- Author
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Yasuo Nakagawa, Shinya Hanashima, Tomoya Yamamoto, Tohru Oishi, Naohiro Matsushita, Michio Murata, Yuichi Umegawa, Hiroshi Tsuchikawa, and Nobuaki Matsumori
- Subjects
0301 basic medicine ,Models, Molecular ,Fluorine Radioisotopes ,Antifungal Agents ,Magnetic Resonance Spectroscopy ,Trimethylsilyl ,Stereochemistry ,animal diseases ,Lipid Bilayers ,Molecular Conformation ,010402 general chemistry ,Antiparallel (biochemistry) ,01 natural sciences ,Biochemistry ,Ion Channels ,03 medical and health sciences ,chemistry.chemical_compound ,Streptomyces nodosus ,Amphotericin B ,Ergosterol ,parasitic diseases ,Moiety ,Lipid bilayer ,Carbon Isotopes ,030102 biochemistry & molecular biology ,biology ,urogenital system ,Circular Dichroism ,Cell Membrane ,Provitamins ,technology, industry, and agriculture ,Nuclear magnetic resonance spectroscopy ,bacterial infections and mycoses ,biology.organism_classification ,Polyene ,0104 chemical sciences ,chemistry - Abstract
Amphotericin B (AmB) is a polyene macrolide antibiotic isolated from Streptomyces nodosus. The antifungal activity of AmB can be attributed to the formation of an ion-channel assembly in the presence of ergosterol (Erg), in which there are two different AmB-Erg orientations, parallel and antiparallel, as reported previously. In this study, to elucidate the structures of those AmB-Erg complexes based on solid-state nuclear magnetic resonance, a (19)F-labeled AmB derivative was newly prepared by a hybrid synthesis that utilized degradation products from the drug. Using the 2-(trimethylsilyl)ethoxymethyl (SEM) group as the protecting group for the carboxylic acid moiety of AmB, the fully deprotected labeled AmB compounds were obtained successfully. Then, these labeled AmBs were subjected to (13)C{(19)F} rotational-echo double-resonance (REDOR) experiments in hydrated lipid bilayers. The results indicated the coexistence of parallel and antiparallel orientations for AmB and Erg pairing, at a ratio of 7:3. A total of six distances between AmB and Erg were successfully obtained. Geometry analysis using the distance constraints derived from the REDOR experiments provided the plausible AmB-Erg complex structure for both the parallel and antiparallel interactions. The flat macrolide of AmB and the tetracyclic core of Erg closely contacted in a face-to-face manner, thus maximizing the van der Waals interaction between the two molecules. This interaction can be attributed to the coexistence of both the parallel and antiparallel orientations.
- Published
- 2016
26. Possible conformation of amphotericin B dimer in membrane-bound assembly as deduced from solid-state NMR
- Author
-
Michio Murata, Yuichi Umegawa, Nobuaki Matsumori, and Takeshi Adachi
- Subjects
Antifungal Agents ,Erythrocytes ,Magnetic Resonance Spectroscopy ,Stereochemistry ,Dimer ,Dephasing ,Lipid Bilayers ,Clinical Biochemistry ,Molecular Conformation ,Pharmaceutical Science ,Hemolysis ,Biochemistry ,chemistry.chemical_compound ,Amphotericin B ,Drug Discovery ,Aspergillosis ,Humans ,Lipid bilayer ,Molecular Biology ,Organic Chemistry ,Resonance (chemistry) ,Monomer ,Membrane ,Solid-state nuclear magnetic resonance ,chemistry ,Covalent bond ,Molecular Medicine ,Aspergillus niger ,Dimerization - Abstract
Aiming for structural analysis of amphotericin B (AmB) ion-channel assemblies in membrane, a covalent dimer was synthesized between 13 C-labled AmB methyl ester and 19 F-labled AmB. The dimer showed slightly weaker but significant biological activities against fungi and red blood cells compared with those of monomeric AmB. Then the dimer was subjected to 13 C{ 19 F}REDOR (Rotational-Echo Double Resonance) experiments in hydrated lipid bilayers. The obtained REDOR dephasing effects were explained by two components; a short 13 C/ 19 F distance (6.9 A) accounting for 23% of the REDOR dephasing, and a longer one (14 A) comprising the rest of the dephasing. The shorter distance is likely to reflect the formation of barrel-stave ion channel.
- Published
- 2012
27. Evaluation of diacylphospholipids as boundary lipids for bacteriorhodopsin from structural and functional aspects
- Author
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Michio Murata, Masashi Sonoyama, Satoshi Kawatake, Yuichi Umegawa, and Shigeru Matsuoka
- Subjects
0301 basic medicine ,Halobacterium salinarum ,Circular dichroism ,Stereochemistry ,Lipid Bilayers ,Biophysics ,010402 general chemistry ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Phosphatidylcholine ,Nuclear Magnetic Resonance, Biomolecular ,Phosphatidylglycerol ,Chromatography ,Photolysis ,biology ,Circular Dichroism ,Bacteriorhodopsin ,Phosphatidylglycerols ,Cell Biology ,Phosphatidic acid ,Phosphatidylserine ,0104 chemical sciences ,030104 developmental biology ,Membrane ,chemistry ,Membrane protein ,Bacteriorhodopsins ,biology.protein ,lipids (amino acids, peptides, and proteins) - Abstract
Reconstituted membranes with diverse diacylphospholipids were prepared by using bacteriorhodopsin (bR) in which the intrinsic lipid content was decreased to 24% of the original while the trimeric structure and photocycle of bR were retained. Four phospholipids with a different headgroup, phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylglycerol (PG), and phosphatidylserine (PS), were adopted for reconstitution. By varying the lipid-protein ratios, the interactions of these phospholipids with bR, as a boundary lipid, were evaluated by solid state (2)H/(31)P NMR, circular dichroism (CD), and laser-flash photolysis. The (31)P NMR results revealed that the headgroup of acidic phosphatidylglycerol (PG) interacts more strongly with bR than that of phosphatidylcholine (PC). CD analysis indicated that the trimetric structure of bR was retained in all the phospholipid-bR preparations at low and medium lipid contents. Acidic lipids PA, PG and PS restored the photocycle activity of bR to an extent comparable to (or slightly lower than) that of the purple membrane while PC caused a marked reduction of the bR photocycle efficiency. Among PGs with different fatty acyl groups, those with mono- and di-unsaturated lipids tended to preserve the photocycle efficiency, whereas the fully saturated lipid did not. These results show that acidic unsaturated phospholipids, particularly dioleoylphosphatidylglycerol (DOPG), have higher affinity for bR and efficiently restore its trimetric structure. The present study suggests that bR reconstituted in DOPG bilayers may possibly be used as a model system for spectroscopic investigations of the lipid-bR interactions with the membrane-integral α-helices, and potentially for a similar type of membrane proteins.
- Published
- 2015
28. Head-to-Tail Interaction between Amphotericin B and Ergosterol Occurs in Hydrated Phospholipid Membrane
- Author
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Hiroshi Tsuchikawa, Michio Murata, Kazuaki Tahara, Yasuo Nakagawa, Nobuaki Matsumori, Tohru Oishi, and Yuichi Umegawa
- Subjects
Models, Molecular ,Antifungal ,Antifungal Agents ,medicine.drug_class ,Stereochemistry ,Lipid Bilayers ,Phospholipid ,Saccharomyces cerevisiae ,Biochemistry ,chemistry.chemical_compound ,Amphotericin B ,Ergosterol ,polycyclic compounds ,medicine ,Nuclear Magnetic Resonance, Biomolecular ,Phospholipids ,Carbon Isotopes ,Molecular interactions ,Chemistry ,Cell Membrane ,Deuterium Exchange Measurement ,Phosphorus Isotopes ,Water ,biochemical phenomena, metabolism, and nutrition ,Resonance (chemistry) ,Membrane ,Pairing ,Phosphatidylcholines ,lipids (amino acids, peptides, and proteins) ,medicine.drug - Abstract
Amphotericin B (AmB) is thought to exert its antifungal activity by forming an ion-channel assembly in the presence of ergosterol. In the present study we aimed to elucidate the mode of molecular interactions between AmB and ergosterol in hydrated phospholipid bilayers using the rotational echo double resonance (REDOR) spectra. We first performed (13)C{(19)F}REDOR experiments with C14-(19)F-labeled AmB and biosynthetically (13)C-labeled ergosterol and implied that both "head-to-head" and "head-to-tail" orientations occur for AmB-ergosterol interaction in the bilayers. To further confirm the "head-to-tail" pairing, (13)C-labeled ergosterol at the dimethyl terminus (C26/C27) was synthesized and subjected to the REDOR measurements. The spectra unambiguously demonstrated the presence of a "head-to-tail" orientation for AmB-ergosterol pairing. In order to obtain information on the position of the dimethyl terminus of ergosterol in membrane, (13)C{(31)P}REDOR were carried out using the labeled ergosterol and the phosphorus atom of a POPC headgroup. Significant REDOR dephasing was observed at the C26/C27 signal of ergosterol in the presence of AmB, but not in the absence of AmB, clearly indicating that the side-chain terminus of ergosterol in the AmB complex comes close to the bilayer surface.
- Published
- 2011
29. Ion channel complex of antibiotics as viewed by NMR
- Author
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Yusuke Kasai, Yuichi Umegawa, Naohiro Matsushita, Michio Murata, Hiroshi Tsuchikawa, Nobuaki Matsumori, and Tohru Oishi
- Subjects
Ergosterol ,urogenital system ,Chemistry ,Stereochemistry ,General Chemical Engineering ,technology, industry, and agriculture ,General Chemistry ,bacterial infections and mycoses ,Polyene ,chemistry.chemical_compound ,Ion channel complex ,Solid-state nuclear magnetic resonance ,Covalent bond ,parasitic diseases ,Moiety ,lipids (amino acids, peptides, and proteins) ,Lipid bilayer ,Conjugate - Abstract
Amphotericin B (AmB) exerts its pharmacological effects by forming a barrel-stave assembly in fungal membranes. To examine the interaction between AmB and ergosterol or cholesterol, 13C- and 19F-labeled covalent conjugates were prepared and subjected to solid-state NMR measurements. Using rotor-synchronous double resonance experiments such as REDOR and RDX, we estimated the distance between the fluorine atom and its nearest carbon in the heptaene moiety to be less than 8.6 Å, indicating that the B ring of ergosterol comes close to the AmB polyene moiety. Conformational search of the AmB-ergosterol conjugate using the NMR-derived constraints suggested that ergosterol molecules surround the AmB assembly in contrast to the conventional image where ergosterol is inserted into AmB molecules. AmB-AmB bimolecular interaction was examined by using 13C- and 19F-labeld AmBs in dimyritoylphosphatidylcholine membrane without sterols. 13C-19F dipolar interactions deriving from both head-to-head and head-to-tail orientations were observed in the REDOR experiments. The interactions between AmB and acyl chains of the phospholipid were also detected.
- Published
- 2009
30. Amphotericin B covalent dimers with carbonyl-amino linkage: a new probe for investigating ion channel assemblies
- Author
-
Michio Murata, Nobuaki Matsumori, Tohru Oishi, and Yuichi Umegawa
- Subjects
chemistry.chemical_compound ,Stereochemistry ,Chemistry ,Covalent bond ,Dimer ,Organic Chemistry ,Drug Discovery ,Molecule ,Biochemistry ,Linker ,Ion channel ,Ion - Abstract
Based on an amphotericin B (AmB) ion-channel model where the close proximity of neighboring molecules is effected by interaction between carboxyl and amino groups, we prepared covalent dimers of AmB connected between these functionalities. While directly connected and short-tethered derivatives (2 and 3) lacked the activities, dimer 4 with a longer linker revealed K+ ion flux activity, suggesting that some distance and/or flexibility between the carboxyl and amino groups in adjacent molecules is required for the formation of ion-permeable complex in biomembranes.
- Published
- 2007
31. Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin-lipid interactions
- Author
-
Nobuaki Matsumori, Michio Murata, Yuichi Umegawa, Satoshi Kawatake, Fuminori Sato, Masaki Yamagami, Jin Cui, Sébastien Lethu, and Shigeru Matsuoka
- Subjects
chemistry.chemical_classification ,Liposome ,biology ,Chemistry ,Stereochemistry ,Organic Chemistry ,Phospholipid ,Molecular Conformation ,Bacteriorhodopsin ,Stereoisomerism ,Biochemistry ,chemistry.chemical_compound ,Membrane ,Bacteriorhodopsins ,biology.protein ,Proton NMR ,Moiety ,Organic chemistry ,Physical and Theoretical Chemistry ,Alkyl ,Phospholipids - Abstract
Phosphatidylglycerophosphate methyl ester (PGP-Me), a major constituent of the archaeal purple membrane, is essential for the proper proton-pump activity of bacteriorhodopsin (bR). We carried out the first synthesis of the bisphosphate head group of PGP-Me using H-phosphonate chemistry that led to the production of a simplified PGP-Me analogue with straight alkyl chains. To investigate the role of this head group in the structural and functional integrity of bR, the analogue was used to reconstitute bR into liposomes, in which bR retained the original trimeric structure and light-induced photocycle activity. Enhanced ordering of an alkyl chain of the (2)H-labelled analogue was observed in (2)H NMR spectra upon interaction with bR. These results together suggest that the bisphosphate moiety plays a role in the proper functioning of bR through the lipid-protein interaction.
- Published
- 2015
32. (13) C-TmDOTA as versatile thermometer compound for solid-state NMR of hydrated lipid bilayer membranes
- Author
-
Yuichi, Umegawa, Yuya, Tanaka, Matsumori, Nobuaki, and Michio, Murata
- Abstract
Recent advances in solid-state nuclear magnetic resonance (NMR) techniques, such as magic angle spinning and high-power decoupling, have dramatically increased the sensitivity and resolution of NMR. However, these NMR techniques generate extra heat, causing a temperature difference between the sample in the rotor and the variable temperature gas. This extra heating is a particularly crucial problem for hydrated lipid membrane samples. Thus, to develop an NMR thermometer that is suitable for hydrated lipid samples, thulium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (TmDOTA) was synthesized and labeled with (13) C (i.e., (13) C-TmDOTA) to increase the NMR sensitivity. The complex was mixed with a hydrated lipid membrane, and the system was subjected to solid-state NMR and differential scanning calorimetric analyses. The physical properties of the lipid bilayer and the quality of the NMR spectra of the membrane were negligibly affected by the presence of (13) C-TmDOTA, and the (13) C chemical shift of the complex exhibited a large-temperature dependence. The results demonstrated that (13) C-TmDOTA could be successfully used as a thermometer to accurately monitor temperature changes induced by (1) H decoupling pulses and/or by magic angle spinning and the temperature distribution of the sample inside the rotor. Thus, (13) C-TmDOTA was shown to be a versatile thermometer for hydrated lipid assemblies. Copyright © 2015 John WileySons, Ltd.
- Published
- 2015
33. Centerband-only analysis of rotor-unsynchronized spin echo for measurement of lipid (31) P chemical shift anisotropy
- Author
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Yuichi, Umegawa, Toshiyuki, Yamaguchi, Michio, Murata, and Shigeru, Matsuoka
- Subjects
Magnetic Resonance Spectroscopy ,Molecular Structure ,Lipid Bilayers ,Anisotropy ,Phosphorus ,Reference Standards ,Phospholipids - Abstract
Structural diversity and molecular flexibility of phospholipids are essential for biological membranes to play key roles in numerous cellular processes. Uncovering the behavior of individual lipids in membrane dynamics is crucial for understanding the molecular mechanisms underlying biological functions of cell membranes. In this paper, we introduce a simple method to investigate dynamics of lipid molecules in multi-component systems by measuring the (31) P chemical shift anisotropy (CSA) under magic angle spinning (MAS) conditions. For achieving both signal separation and CSA determination, we utilized a centerband-only analysis of rotor-unsynchronized spin echo (COARSE). This analysis is based on the curve fitting of periodic modulation of centerband intensity along the interpulse delay time in rotor-unsynchronized spin-echo experiments. The utility of COARSE was examined by using phospholipid vesicles, a three-component lipid raft model system, and archaeal purple membranes. We found that the apparent advantages of this method are high resolution and high sensitivity given by the moderate MAS speed and the one-dimensional acquisition with short spin-echo delays. COARSE provides an alternative method for CSA measurement that is effective in the investigation of lipid polymorphologies.
- Published
- 2014
34. Ergosterol increases the intermolecular distance of amphotericin B in the membrane-bound assembly as evidenced by solid-state NMR
- Author
-
Tohru Oishi, Michio Murata, Nobuaki Matsumori, and Yuichi Umegawa
- Subjects
Models, Molecular ,Magnetic Resonance Spectroscopy ,Stereochemistry ,Ultraviolet Rays ,Lipid Bilayers ,Molecular Conformation ,Biochemistry ,Biophysical Phenomena ,Ion Channels ,chemistry.chemical_compound ,Amphotericin B ,Ergosterol ,parasitic diseases ,Molecule ,Lipid bilayer ,POPC ,urogenital system ,Chemistry ,Intermolecular force ,technology, industry, and agriculture ,bacterial infections and mycoses ,Streptomyces ,Crystallography ,Membrane ,Cholesterol ,Solid-state nuclear magnetic resonance ,Models, Chemical ,Absorption band ,Phosphatidylcholines ,lipids (amino acids, peptides, and proteins) ,Spectrophotometry, Ultraviolet ,Protein Binding - Abstract
Amphotericin B (AmB) exerts its antifungal activity by forming ion-permeable assemblies across lipid bilayers. To investigate AmB-AmB bimolecular interactions in the assembly, we carried out (13)C{(19)F}REDOR experiments using 14-(19)F- and (13)C41-labeled AmBs in sterol-containing and sterol-free palmitoyloleoylphosphatidylcholine (POPC) membranes and measured the average distance between the labeled sites of AmBs in membrane-bound forms. The REDOR results suggested that the intermolecular distance of AmB molecules is significantly increased in the ergosterol membrane as compared with the cholesterol membrane. This sterol-dependent change was supported by the UV spectra of AmB in lipid bilayers, in which the excitonic absorption band arising from the aggregated state of AmB shifted to longer wavelength in ergosterol-containing POPC membrane. The REDOR experiments also disclosed that the head-to-head orientation of AmB is predominant in both of the sterol-containing membranes and AmB-POPC interaction was detected only in the ergosterol membrane. Ergosterol significantly influences the interactions between AmB molecules as well as those between AmB and POPC, which may facilitate formation of ion-permeable channels in ergosterol-containing membrane.
- Published
- 2008
35. Self-assembled amphotericin B is probably surrounded by ergosterol: bimolecular interactions as evidenced by solid-state NMR and CD spectra
- Author
-
Tohru Oishi, Hiroyuki Ueno, Yusuke Kasai, Nobuaki Matsumori, Yuichi Umegawa, Michio Murata, Shigeru Matsuoka, and Hiroki Ikeuchi
- Subjects
Models, Molecular ,Circular dichroism ,Fluorine Radioisotopes ,Magnetic Resonance Spectroscopy ,Stereochemistry ,Molecular Conformation ,Catalysis ,chemistry.chemical_compound ,Amphotericin B ,Ergosterol ,polycyclic compounds ,Moiety ,Carbon Isotopes ,Circular Dichroism ,Organic Chemistry ,technology, industry, and agriculture ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,bacterial infections and mycoses ,Polyene ,NMR spectra database ,Membrane ,Cholesterol ,chemistry ,Covalent bond ,lipids (amino acids, peptides, and proteins) - Abstract
Amphotericin B (AmB) is thought to exert its pharmacological effects by forming a barrel-stave assembly with ergosterol in fungal membranes. To examine the interaction between AmB and ergosterol (Erg) or cholesterol (Cho), (13)C- and (19)F-labelled covalent conjugates were prepared as reported previously (N. Matsumori et al. Chem. Biol. 2004, 11, 673-679). The CD spectra of the conjugates in a membrane-bound form suggested that the distance between the heptaene moieties of the ergosterol conjugates AmB-C(2)-(6-F)Erg 2 and AmB-C(2)-Erg 3 is similar to that of AmB in ergosterol-containing membranes, but significantly larger than that of AmB in nonsterol or cholesterol-containing membranes. These observations suggest that, as is the case with ergosterol-containing membranes, the conjugated sterol moiety prevents the close contact between the heptaene moieties within the membrane that would reduce channel conductivity of the AmB assemblies. To further investigate this bimolecular interaction, we recorded the solid-state NMR spectra of conjugates 2 and AmB-C(2)-(6-F)Cho 4, which are composed of uniformly (13)C-labelled AmB and 6-fluorinated ergosterol or cholesterol; the conjugates were expected to facilitate the estimation of distances between the fluorine and carbon atoms. By using rotor-synchronous double resonance (rotational echo double resonance of X cluster; RDX) experiments, we deduced the distance between the fluorine atom and its nearest carbon atom in the heptaene moiety of 2 to be less than 8.6 A. This indicates that the B ring of ergosterol comes close to the AmB polyene moiety. A conformational search of the AmB-ergosterol conjugate by using distance constraints derived from the RDX results suggested that ergosterol molecules possibly surround the AmB assembly, which is in contrast with the conventional image in which ergosterol is inserted into AmB molecules.
- Published
- 2007
36. Correction: Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin–lipid interactions
- Author
-
Yuichi Umegawa, Shigeru Matsuoka, Michio Murata, Nobuaki Matsumori, Fuminori Sato, Sébastien Lethu, Masaki Yamagami, Satoshi Kawatake, and Jin Cui
- Subjects
chemistry.chemical_compound ,biology ,Stereochemistry ,Chemistry ,Group (periodic table) ,Organic Chemistry ,biology.protein ,Phospholipid ,Head (vessel) ,Stereoselectivity ,Bacteriorhodopsin ,Physical and Theoretical Chemistry ,Biochemistry - Abstract
Correction for ‘Stereoselective synthesis of the head group of archaeal phospholipid PGP-Me to investigate bacteriorhodopsin–lipid interactions’ by Jin Cui, et al., Org. Biomol. Chem., 2015, DOI: 10.1039/c5ob01252j.
- Published
- 2015
37. Membrane interaction of amphotericin B as single-length assembly examined by solid state NMR for uniformly 13C-enriched agent
- Author
-
Hiroki Ikeuchi, Michio Murata, Nobuaki Matsumori, Yuichi Umegawa, and Shigeru Matsuoka
- Subjects
Antifungal Agents ,Magnetic Resonance Spectroscopy ,Stereochemistry ,Clinical Biochemistry ,Phospholipid ,Pharmaceutical Science ,Biochemistry ,chemistry.chemical_compound ,Phosphatidylcholine ,Amphotericin B ,Drug Discovery ,Lipid bilayer ,Molecular Biology ,chemistry.chemical_classification ,Carbon Isotopes ,Organic Chemistry ,Carbon-13 ,Membranes, Artificial ,Carbon-13 NMR ,Streptomyces ,Membrane ,chemistry ,Aldose ,Solid-state nuclear magnetic resonance ,Phosphatidylcholines ,Molecular Medicine ,Indicators and Reagents - Abstract
The membrane interaction of amphotericin B (AmB), one of the most important anti-fungal drugs, was investigated by solid state NMR measurements of uniformly 13 C-enriched AmB, which was prepared by the culture of the drug-producing microorganism in the presence of [u- 13 C 6 ]glucose. All the 13 C NMR signals of AmB upon binding to DLPC membrane were successfully assigned on the basis of the 13 C– 13 C correlation spectrum. 13 C– 31 P RDX (Rotational-Echo Double Resonance for X-clusters) experiments clearly revealed the REDOR dephasing effects for carbon atoms residing in the both terminal parts, whereas no dephasing was observed for the middle parts including polyolefinic C20–C33 and hydroxyl-bearing C8/C9 parts. These observations suggest that AmB binds to DLPC membrane with a high affinity to the phospholipid and spans the membrane with a single molecular length.
- Published
- 2006
38. Bioactive fluorinated derivative of amphotericin B
- Author
-
Michio Murata, Nobuaki Matsumori, Yuichi Umegawa, and Tohru Oishi
- Subjects
Antifungal ,Antifungal Agents ,Magnetic Resonance Spectroscopy ,medicine.drug_class ,Clinical Biochemistry ,Pharmaceutical Science ,chemistry.chemical_element ,Biochemistry ,Chemical synthesis ,Ion Channels ,chemistry.chemical_compound ,Amphotericin B ,Drug Discovery ,medicine ,Organic chemistry ,Humans ,Cytotoxicity ,Molecular Biology ,Organic Chemistry ,Electrophilic fluorination ,Stereoisomerism ,General Medicine ,Fluorine ,Combinatorial chemistry ,chemistry ,Reagent ,Molecular Medicine ,Macrolides ,Selectfluor ,Derivative (chemistry) ,medicine.drug - Abstract
The first stably fluorinated derivative of amphotericin B ( 2 ) with a fluorine atom in the macrolide skeleton was synthesized using an electrophilic fluorination reagent, Selectfluor ® . The derivative 2 showed hemolytic, K + permeable, and antifungal activities similar to those of AmB and thus was expected to be a powerful tool for NMR-based investigations on the mechanism of ion-channel formation by amphotericin B.
- Published
- 2005
39. Effect of Sterol Side Chain on Ion Channel Formation by Amphotericin B in Lipid Bilayers.
- Author
-
Yasuo Nakagawa, Yuichi Umegawa, Tetsuro Takano, Hiroshi Tsuchikawa, Nobuaki Matsumori, and Michio Murata
- Subjects
- *
STEROLS , *AMPHOTERICIN B , *ION channels , *BILAYER lipid membranes , *ANTIFUNGAL agents , *ERGOSTEROL - Abstract
Amphotericin B (AmB) is one of the most efficient antimycotic drugs used in clinical practice. AmB interacts with membrane sterols increasing permeability of fungal membranes; however, it is still unclear how AmB selectively recognizes the fungal sterol, ergosterol (Erg), over other sterols in cell membranes. In this study, we investigated the effect of an Erg side chain on AmB activity by testing a series of Erg analogues that shared the same alicyclic structure as Erg but varied in the side chain structure by using the K+ influx assay. The results clearly showed that the sterol side chain is essential for AmB selectivity toward Erg and for the activity of AmB-sterol ion channels. In agreement with our previous findings showing the direct interaction between the drug and Erg, these data suggested that AmB directly recognizes the sterol side chain structure, consequently promoting the formation of ion channels by AmB. Furthermore, the C24 methyl group and Δ22 double bond in the side chain of Erg are equally important for the interaction with AmB. Conformational analysis revealed that the C24 methyl group contributes to the interaction by increasing the van der Waals (VDW) contact area of the side chain, while the Δ22 double bond restricts the side chain conformation to maximize the VDW contact with the rigid AmB aglycone. This study provides direct experimental evidence of the mechanism of AmB selectivity toward fungal Erg. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
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