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Galván-Hernández A, Kobayashi N, Hernández-Cobos J, Antillón A, Nakabayashi S, Ortega-Blake I. Morphology and dynamics of domains in ergosterol or cholesterol containing membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183101. [DOI: 10.1016/j.bbamem.2019.183101] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/02/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022]
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2
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Bui TT, Suga K, Kuhl TL, Umakoshi H. Melting-Temperature-Dependent Interactions of Ergosterol with Unsaturated and Saturated Lipids in Model Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:10640-10647. [PMID: 31310548 DOI: 10.1021/acs.langmuir.9b01538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Sterols such as cholesterol (Chol) and ergosterol (Erg) are known to regulate membrane properties in higher eukaryotes and in lower eukaryotes, respectively. To better understand the modulation of membrane properties by Erg, binary lipid membranes composed of Erg and diacylglycerophosphocholine (PC) were studied in Langmuir monolayer and bilayer vesicle systems. From the excess area measured by pressure-area isotherms, attractive interactions between Erg and saturated PC were significant above the melting temperature (Tm) of PC. Conversely, repulsive interactions were observed at temperatures below Tm. From the analyses of membrane fluidity and polarity using fluorescence probes, similar trends were observed for bilayer systems where Erg had an ordering effect on saturated PC vesicles in the fluid state. However, Chol had a stronger ordering effect than Erg. In unsaturated PC systems, Erg did not alter membrane ordering. These findings demonstrate that the interaction of Erg with the fluid-state PC lipids will maintain lower-eukaryote membranes in a more ordered state, similar to the effect of cholesterol in higher eukaryotes.
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Affiliation(s)
- Tham Thi Bui
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | - Keishi Suga
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
| | | | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama-cho , Toyonaka , Osaka 560-8531 , Japan
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3
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Bui TT, Suga K, Umakoshi H. Ergosterol-Induced Ordered Phase in Ternary Lipid Mixture Systems of Unsaturated and Saturated Phospholipid Membranes. J Phys Chem B 2019; 123:6161-6168. [DOI: 10.1021/acs.jpcb.9b03413] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Tham Thi Bui
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Keishi Suga
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
| | - Hiroshi Umakoshi
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan
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4
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Hung WC, Lee MT, Chung H, Sun YT, Chen H, Charron NE, Huang HW. Comparative Study of the Condensing Effects of Ergosterol and Cholesterol. Biophys J 2017; 110:2026-33. [PMID: 27166810 DOI: 10.1016/j.bpj.2016.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/04/2016] [Accepted: 04/05/2016] [Indexed: 10/21/2022] Open
Abstract
Cholesterol, due to its condensing effect, is considered an important regulator of membrane thickness. Other sterols, due to their structural similarities to cholesterol, are often assumed to have a universal effect on membrane properties similar to the condensing effect of cholesterol, albeit possibly to different degrees. We used x-ray diffraction to investigate this assumption. By the combination of lamellar diffraction and grazing-angle scattering, we measured the membrane thickness and the tilt-angle distribution of the lipid's hydrocarbon chains. This method is sensitive to phase separation, which is important for examining the miscibility of sterols and phospholipids. Mixtures of ergosterol or cholesterol with dimyristoylphosphatidylcholine, palmitoyloleoylphosphatidylcholine, and dioleoylphosphatidylcholine were systematically studied. We found that mixing ergosterol with phospholipids into a single phase became increasingly difficult with higher sterol concentrations and also with higher concentrations of unsaturated lipid chains. The only condensing effect of ergosterol was found in dimyristoylphosphatidylcholine, although the effect was less than one-third of the effect of cholesterol. Unlike cholesterol, ergosterol could not maintain a fixed electron density profile of the surrounding lipids independent of hydration. In dioleoylphosphatidylcholine and palmitoyloleoylphosphatidylcholine, ergosterol made the membranes thinner, opposite to the effect of cholesterol. In all cases, the tilt-angle variation of the chain diffraction was consistent with the membrane thickness changes measured by lamellar diffraction, i.e., a thickening was always associated with a reduction of chain tilt angles. Our findings do not support the notion that different sterols have a universal behavior that differs only in degree.
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Affiliation(s)
- Wei-Chin Hung
- Department of Physics, Republic of China Military Academy, Fengshan, Kaohsiung, Taiwan
| | - Ming-Tao Lee
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan; Department of Physics, National Central University, Jhongli, Taiwan
| | - Hsien Chung
- Department of Physics, Republic of China Military Academy, Fengshan, Kaohsiung, Taiwan
| | - Yi-Ting Sun
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan; Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, Taiwan
| | - Hsiung Chen
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan
| | | | - Huey W Huang
- Department of Physics and Astronomy, Rice University, Houston, Texas.
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5
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Di Scala C, Baier CJ, Evans LS, Williamson PT, Fantini J, Barrantes FJ. Relevance of CARC and CRAC Cholesterol-Recognition Motifs in the Nicotinic Acetylcholine Receptor and Other Membrane-Bound Receptors. CURRENT TOPICS IN MEMBRANES 2017; 80:3-23. [DOI: 10.1016/bs.ctm.2017.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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6
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A mirror code for protein-cholesterol interactions in the two leaflets of biological membranes. Sci Rep 2016; 6:21907. [PMID: 26915987 PMCID: PMC4768152 DOI: 10.1038/srep21907] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/29/2016] [Indexed: 11/29/2022] Open
Abstract
Cholesterol controls the activity of a wide range of membrane receptors through specific interactions and identifying cholesterol recognition motifs is therefore critical for understanding signaling receptor function. The membrane-spanning domains of the paradigm neurotransmitter receptor for acetylcholine (AChR) display a series of cholesterol consensus domains (referred to as “CARC”). Here we use a combination of molecular modeling, lipid monolayer/mutational approaches and NMR spectroscopy to study the binding of cholesterol to a synthetic CARC peptide. The CARC-cholesterol interaction is of high affinity, lipid-specific, concentration-dependent, and sensitive to single-point mutations. The CARC motif is generally located in the outer membrane leaflet and its reverse sequence CRAC in the inner one. Their simultaneous presence within the same transmembrane domain obeys a “mirror code” controlling protein-cholesterol interactions in the outer and inner membrane leaflets. Deciphering this code enabled us to elaborate guidelines for the detection of cholesterol-binding motifs in any membrane protein. Several representative examples of neurotransmitter receptors and ABC transporters with the dual CARC/CRAC motifs are presented. The biological significance and potential clinical applications of the mirror code are discussed.
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7
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Ho LK, Nodwell JR. David and Goliath: chemical perturbation of eukaryotes by bacteria. J Ind Microbiol Biotechnol 2015; 43:233-48. [PMID: 26433385 PMCID: PMC4752587 DOI: 10.1007/s10295-015-1686-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 09/09/2015] [Indexed: 12/20/2022]
Abstract
Environmental microbes produce biologically active small molecules that have been mined extensively as antibiotics and a smaller number of drugs that act on eukaryotic cells. It is known that there are additional bioactives to be discovered from this source. While the discovery of new antibiotics is challenged by the frequent discovery of known compounds, we contend that the eukaryote-active compounds may be less saturated. Indeed, despite there being far fewer eukaryotic-active natural products these molecules interact with a far richer diversity of molecular and cellular targets.
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Affiliation(s)
- Louis K Ho
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Justin R Nodwell
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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8
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9
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Kamiński DM, Pociecha D, Górecka E, Gagoś M. The influence of amphotericin B on the molecular organization and structural properties of DPPC lipid membranes modified by sterols. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2014.10.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Nakagawa Y, Umegawa Y, Nonomura K, Matsushita N, Takano T, Tsuchikawa H, Hanashima S, Oishi T, Matsumori N, Murata M. Axial Hydrogen at C7 Position and Bumpy Tetracyclic Core Markedly Reduce Sterol’s Affinity to Amphotericin B in Membrane. Biochemistry 2015; 54:303-12. [DOI: 10.1021/bi5012942] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yasuo Nakagawa
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yuichi Umegawa
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kenichi Nonomura
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Naohiro Matsushita
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Tetsuro Takano
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Hiroshi Tsuchikawa
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shinya Hanashima
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Tohru Oishi
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Nobuaki Matsumori
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- Department of Chemistry,
Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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11
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Gagoś M, Arczewska M. FTIR spectroscopic study of molecular organization of the antibiotic amphotericin B in aqueous solution and in DPPC lipid monolayers containing the sterols cholesterol and ergosterol. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:663-73. [DOI: 10.1007/s00249-012-0842-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/29/2012] [Accepted: 07/10/2012] [Indexed: 10/28/2022]
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12
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Benesch MGK, Mannock DA, Lewis RNAH, McElhaney RN. A Calorimetric and Spectroscopic Comparison of the Effects of Lathosterol and Cholesterol on the Thermotropic Phase Behavior and Organization of Dipalmitoylphosphatidylcholine Bilayer Membranes. Biochemistry 2011; 50:9982-97. [DOI: 10.1021/bi200721j] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Matthew G. K. Benesch
- Department of Biochemistry, School of Translational
Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - David A. Mannock
- Department of Biochemistry, School of Translational
Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Ruthven N. A. H. Lewis
- Department of Biochemistry, School of Translational
Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
| | - Ronald N. McElhaney
- Department of Biochemistry, School of Translational
Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7
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13
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Xu ZH, Peng XP, Wang Y, Zhu WM. (22E,24R)-3β,5α,9α-Trihy-droxy-ergosta-7,22-dien-6-one monohydrate. Acta Crystallogr Sect E Struct Rep Online 2011; 67:o1141-2. [PMID: 21754450 PMCID: PMC3089332 DOI: 10.1107/s160053681101347x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 04/11/2011] [Indexed: 11/28/2022]
Abstract
The title ergosterol compound, C28H44O4·H2O, is composed of four fused rings (three six-membered and one five-membered) and a side chain. It is a derivative of ergosterol and was isolated from a marine-derived halotolerant fungus, Cladosporium cladosporioides PXP-49. In the crystal, molecules are assembled by classical O—H⋯O hydrogen bonds, forming a two-dimensional network, with base vectors [100] and [010]. The absolute configuration was assigned from the measured optical rotation and reference to the literature. An intramolecular O—H⋯O hydrogen bond occurs.
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Affiliation(s)
- Zhi-Hong Xu
- Key Laboratory of Marine Drugs of the Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 266003 Qingdao, People's Republic of China
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14
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Mannock DA, Lewis RN, McMullen TP, McElhaney RN. The effect of variations in phospholipid and sterol structure on the nature of lipid–sterol interactions in lipid bilayer model membranes. Chem Phys Lipids 2010; 163:403-48. [DOI: 10.1016/j.chemphyslip.2010.03.011] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 03/13/2010] [Accepted: 03/27/2010] [Indexed: 01/30/2023]
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15
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Mannock DA, Lewis RN, McElhaney RN. A calorimetric and spectroscopic comparison of the effects of ergosterol and cholesterol on the thermotropic phase behavior and organization of dipalmitoylphosphatidylcholine bilayer membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:376-88. [DOI: 10.1016/j.bbamem.2009.09.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 08/06/2009] [Accepted: 09/06/2009] [Indexed: 11/16/2022]
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16
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Miñones J, Pais S, Miñones J, Conde O, Dynarowicz-Łątka P. Interactions between membrane sterols and phospholipids in model mammalian and fungi cellular membranes — A Langmuir monolayer study. Biophys Chem 2009; 140:69-77. [DOI: 10.1016/j.bpc.2008.11.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/21/2008] [Accepted: 11/22/2008] [Indexed: 10/21/2022]
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17
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Czub J, Neumann A, Borowski E, Baginski M. Influence of a lipid bilayer on the conformational behavior of amphotericin B derivatives - A molecular dynamics study. Biophys Chem 2009; 141:105-16. [PMID: 19185412 DOI: 10.1016/j.bpc.2009.01.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 01/02/2009] [Accepted: 01/04/2009] [Indexed: 11/28/2022]
Abstract
Amphotericin B (AmB) is an effective but very toxic antifungal antibiotic. In our laboratory a series of AmB derivatives of improved selectivity of action was synthesized and tested. To understand molecular basis of this improvement, comparative conformational studies of amphotericin B and its two more selective derivatives were carried out in an aqueous solution and in a lipid membrane. These molecular simulation studies revealed that within a membrane environment the conformational behavior of the derivatives differs significantly from the one observed for the parent molecule. Possible reasons for such a difference are analyzed. Furthermore, we hypothesize that the observed conformational transition within the polar head of AmB derivatives may lead to destabilization of antibiotic-induced transmembrane channels. Consequently, the selective toxicity of the derivatives should increase as ergosterol-rich liquid-ordered domains are more rigid and conformationally ordered than their cholesterol-containing counterparts, and as such may better support less stable channel structure.
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Affiliation(s)
- Jacek Czub
- Department of Pharmaceutical Technology and Biochemistry, Gdansk University of Technology, Poland
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18
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Ordering effects of cholesterol and its analogues. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:97-121. [DOI: 10.1016/j.bbamem.2008.08.022] [Citation(s) in RCA: 450] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 08/27/2008] [Accepted: 08/31/2008] [Indexed: 12/12/2022]
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19
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Welscher YMT, Napel HHT, Balagué MM, Souza CM, Riezman H, de Kruijff B, Breukink E. Natamycin Blocks Fungal Growth by Binding Specifically to Ergosterol without Permeabilizing the Membrane. J Biol Chem 2008; 283:6393-401. [DOI: 10.1074/jbc.m707821200] [Citation(s) in RCA: 169] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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20
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Cournia Z, Ullmann GM, Smith JC. Differential Effects of Cholesterol, Ergosterol and Lanosterol on a Dipalmitoyl Phosphatidylcholine Membrane: A Molecular Dynamics Simulation Study. J Phys Chem B 2007; 111:1786-801. [PMID: 17261058 DOI: 10.1021/jp065172i] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lipid raft/domain formation may arise as a result of the effects of specific sterols on the physical properties of membranes. Here, using molecular dynamics simulation, we examine the effects of three closely-related sterols, ergosterol, cholesterol, and lanosterol, at a biologically relevant concentration (40 mol %) on the structural properties of a model dipalmitoyl phosphatidylcholine (DPPC) membrane at 309 and 323 K. All three sterols are found to order the DPPC acyl tails and condense the membrane relative to the DPPC liquid-phase membrane, but each one does this to a significantly different degree. The smooth alpha-face of ergosterol, together with the presence of tail unsaturation in this sterol, leads to closer interaction of ergosterol with the lipids and closer packing of the lipids with each other, so ergosterol has a higher condensing effect on the membrane, as reflected by the area per lipid. Moreover, ergosterol induces a higher proportion of trans lipid conformers, a thicker membrane, and higher lipid order parameters and is aligned more closely with the membrane normal. Ergosterol also positions itself closer to the bilayer/water interface. In contrast, the rough alpha-face of lanosterol leads to a less close interaction of the steroid ring system with the phospholipid acyl chains, and so lanosterol orders, straightens, and packs the lipid acyl chains less well and is less closely aligned with the membrane normal. Furthermore, lanosterol lies closer to the relatively disordered membrane center than do the other sterols. The behavior of cholesterol in all the above respects is intermediate between that of lanosterol and ergosterol. The findings here may explain why ergosterol is the most efficient of the three sterols at promoting the liquid-ordered phase and lipid domain formation and may also furnish part of the explanation as to why cholesterol is evolutionarily preferred over lanosterol in higher-vertebrate plasma membranes.
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Affiliation(s)
- Zoe Cournia
- Computational Molecular Biophysics, Interdisciplinary Center for Scientific Computing (IWR), Im Neuenheimer Feld 368, Universität Heidelberg, 69120 Heidelberg, Germany
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21
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Baginski M, Czub J, Sternal K. Interaction of amphotericin B and its selected derivatives with membranes: molecular modeling studies. CHEM REC 2007; 6:320-32. [PMID: 17304519 DOI: 10.1002/tcr.20096] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Amphotericin B (AmB) is a well-known antifungal antibiotic that has been used in the clinic for about five decades. Despite its chemotherapeutic importance, AmB is quite toxic and many efforts have been made to improve its pharmacological properties, e.g., by chemical modifications. The lipid membrane is a molecular target for AmB, however, due to heterogeneity of its components, the molecular mechanism of AmB action is still unclear. The lack of this knowledge hinders rational designing of new and less toxic AmB derivatives. Our review is a critical presentation of the current understanding of AmB molecular mechanism of action at the membrane level. Except the experimental approach, the extensive overview of molecular modeling studies, performed mostly in our lab, is presented. The results of interactions between AmB or some of its derivatives and lipid model membranes are discussed. In our studies, different biomembrane models and different associate states of the antibiotic were included. Presented molecular modeling approach is especially valuable with regard to a new paradigm of the structure of lipid membrane containing liquid-ordered domains. Hopefully, all these complementary experimental/computational approaches are going to reach the point at which a new hypothesis about molecular mechanism of AmB activity and selectivity will be put forward.
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Affiliation(s)
- Maciej Baginski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-952 Gdansk, Poland.
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22
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Czub J, Baginski M. Comparative molecular dynamics study of lipid membranes containing cholesterol and ergosterol. Biophys J 2006; 90:2368-82. [PMID: 16399829 PMCID: PMC1403193 DOI: 10.1529/biophysj.105.072801] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sterol molecules are essential for maintaining the proper structure and function of eukaryotic cell membranes. The influence of cholesterol (the principal sterol of higher animals) on the lipid bilayer properties was extensively studied by both experimental and simulation methods. In contrast, the effect of ergosterol (the principal fungal sterol) on the membrane structure and dynamics is much less recognized. This work presents the results of comparative molecular dynamics simulation of the hydrated dimyristoylphosphatidylcholine bilayer containing approximately 25 mol % of cholesterol or ergosterol. A detailed analysis of the molecular properties (e.g., bilayer thickness, lipid order, diffusion, intermolecular interactions, etc.) of both sterol-induced liquid-ordered membrane phases is presented. Presence of sterols in the membrane significantly changes its property, especially fluidity and molecular packing. Moreover, in accordance with the experiments, our calculations show that, compared to cholesterol, ergosterol has higher ordering effect on the phospholipid acyl chains. This different influence on the properties of the lipid bilayer stems from differences in conformational freedom of sterol side chains. Additionally, obtained models of lipid membranes containing human and fungal sterols, constituting the result of our work, can be also utilized in other chemotherapeutic studies on interaction of selected ligands (e.g., antifungal compounds) with membranes.
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Affiliation(s)
- Jacek Czub
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gdansk, Poland
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23
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Baginski M, Cybulska B, Gruszecki WI. Chapter 9 Interaction of Polyene Macrolide Antibiotics with Lipid Model Membranes. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1554-4516(05)03009-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
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24
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Ruge E, Korting HC, Borelli C. Current state of three-dimensional characterisation of antifungal targets and its use for molecular modelling in drug design. Int J Antimicrob Agents 2005; 26:427-41. [PMID: 16289513 DOI: 10.1016/j.ijantimicag.2005.09.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The alarming rise in life-threatening systemic fungal infections due to the emergence of drug-resistant fungal strains had produced an increased demand for new antimycotics, especially those targeting novel antifungal structures. Drug discovery has developed from screening natural products and chemical synthesis to a modern approach, namely structure-based drug design. Whilst many antifungal agents currently in use were discovered more than 30 years ago, characterisation of various drug targets has only been achieved recently, contributing immensely to understanding the structure-activity relationships of antifungals and their targets. Three-dimensional characterisation has become a well established tool for modern antifungal drug research and should play an important role in investigations for new antifungal agents.
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Affiliation(s)
- E Ruge
- Department of Dermatology, University of Munich, Frauenlobstr. 9-11, 80337 Munich, Germany.
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25
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Hac-Wydro K, Dynarowicz-Łatka P, Grzybowska J, Borowski E. Interactions of amphotericin B derivative of low toxicity with biological membrane components—the Langmuir monolayer approach. Biophys Chem 2005; 116:77-88. [PMID: 15911084 DOI: 10.1016/j.bpc.2005.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 03/02/2005] [Accepted: 03/07/2005] [Indexed: 10/25/2022]
Abstract
Amphotericin B (AmB)--a polyene macrolide antibiotic--exhibits strong antifungal activity, however, is known to be very toxic to mammalian cells. In order to decrease AmB toxicity, a number of its derivatives have been synthesized. Basing on in vitro and in vivo research, it was evidenced that one of AmB derivatives, namely N-methyl-N-D-fructopyranosylamphotericin B methyl ester (in short MF-AME) retained most of the antifungal activity of the parent antibiotic, however, exhibited dramatically lower animal toxicity. Therefore, MF-AME seems to be a very promising modification product of AmB. However, further development of this derivative as potential new antifungal drug requires the elucidation of its molecular mechanism of reduced toxicity, which was the aim of the present investigations. Our studies were based on examining the binding energies by determining the strength of interaction between MF-AME and membrane sterols (ergosterol-fungi sterol, and cholesterol-mammalian sterol) and DPPC (model membrane phospholipid) using the Langmuir monolayer technique, which serves as a model of cellular membrane. Our results revealed that at low concentration the affinity of MF-AME to ergosterol is considerably stronger as compared to cholesterol, which correlates with the improved selective toxicity of this drug. It is of importance that the presence of phospholipids is essential since--due to very strong interactions between MF-AME and DPPC--the antibiotic used in higher concentration is "immobilized" by DPPC molecules, which reduces the concentration of free antibiotic, thus enabling it to selectively interact with both sterols.
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Affiliation(s)
- K Hac-Wydro
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
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Baginski M, Resat H, Borowski E. Comparative molecular dynamics simulations of amphotericin B-cholesterol/ergosterol membrane channels. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1567:63-78. [PMID: 12488039 DOI: 10.1016/s0005-2736(02)00581-3] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amphotericin B (AmB) is a very effective anti-fungal polyene macrolide antibiotic whose usage is limited by its toxicity. Lack of a complete understanding of AmB's molecular mechanism has impeded attempts to design less toxic AmB derivatives. The antibiotic is known to interact with sterols present in the cell membrane to form ion channels that disrupt membrane function. The slightly higher affinity of AmB toward ergosterol (dominant sterol in fungal cells) than cholesterol (mammalian sterol) is regarded as the most essential factor on which antifungal chemotherapy is based. To study these differences at the molecular level, two realistic model membrane channels containing molecules of AmB, sterol (cholesterol or ergosterol), phospholipid, and water were studied by molecular dynamics (MD) simulations. Comparative analysis of the simulation data revealed that the sterol type has noticeable effect on the properties of AmB membrane channels. In addition to having a larger size, the AmB channel in the ergosterol-containing membrane has a more pronounced pattern of intermolecular hydrogen bonds. The interaction between the antibiotic and ergosterol is more specific than between the antibiotic and cholesterol. These observed differences suggest that the channel in the ergosterol-containing membrane is more stable and, due to its larger size, would have a higher ion conductance. These observations are in agreement with experiments.
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Affiliation(s)
- Maciej Baginski
- Department of Pharmaceutical Technology and Biochemistry, Chemical Faculty, Technical University of Gdansk, Narutowicza St. 11, 80-952 Gdansk, Poland.
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Charbonneau C, Fournier I, Dufresne S, Barwicz J, Tancrède P. The interactions of amphotericin B with various sterols in relation to its possible use in anticancer therapy. Biophys Chem 2001; 91:125-33. [PMID: 11429202 DOI: 10.1016/s0301-4622(01)00164-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Amphotericin B (AmB) is still the most common anti-fungal agent used to treat systemic fungal infections. It is known that this antibiotic acts by forming pores with the ergosterol contained in the membranes of fungi, but it also interacts with the cholesterol contained in the membranes of eukaryotic cells, hence its toxicity. AmB may also interact with the most common oxidation products of cholesterol found in vivo, together with interacting with biosynthetic precursors of cholesterol, namely, lanosterol and 7-dehydrocholesterol (7-DHC). The purpose of the present work was to study the interactions in solution between AmB and these various sterols, the techniques used being UV-Vis spectroscopy and differential scanning calorimetry. The results are globally interpreted in terms of the structural differences between the sterols. We show that AmB selectively interacts with 7-DHC which, according to a recent hypothesis proposed in the literature, has been identified in connexion with a therapeutic strategy against hepatocellular carcinomas. We find that the affinity of AmB towards 7-DHC is even greater than the affinity of the antibiotic towards ergosterol. We also find that AmB selectively interacts with the principal oxidation product of cholesterol, 7-ketocholesterol, a situation that has to be taken into account when AmB is administered.
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Affiliation(s)
- C Charbonneau
- Département de Chimie-Biologie, Université du Québec à Trois-Rivières, B.P. 500, Trois-Rivières, Québec, Canada G9A 5H7
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Resat H, Sungur FA, Baginski M, Borowski E, Aviyente V. Conformational properties of amphotericin B amide derivatives--impact on selective toxicity. J Comput Aided Mol Des 2000; 14:689-703. [PMID: 11008890 DOI: 10.1023/a:1008144208706] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Even though it is highly toxic, Amphotericin B (AmB), an amphipathic polyene macrolide antibiotic, is used in the treatment of severe systemic fungal infections as a life-saving drug. To examine the influence of conformational factors on selective toxicity of these compounds, we have investigated the conformational properties of five AmB amide derivatives. It was found that the extended conformation with torsional angles (phi,psi)=(290 degrees,180 degrees) is a common minimum of the potential energy surfaces (PES) of unsubstituted AmB and its amide derivatives. The extended conformation of the studied compounds allows for the formation of an intermolecular hydrogen bond network between adjacent antibiotic molecules in the open channel configuration. Therefore, the extended conformation is expected to be the dominant conformer in an open AmB (or its amide derivatives) membrane channel. The derivative compounds for calculations were chosen according to their selective toxicity compared to AmB and they had a wide range of selective toxicity. Except for two AmB derivatives, the PES maps of the derivatives reveal that the molecules can coexist in more than one conformer. Taking into account the cumulative conclusions drawn from the earlier MD simulation studies of AmB membrane channel, the results of the potential energy surface maps, and the physical considerations of the molecular structures, we hypothesize a new model of structure-selective toxicity of AmB derivatives. In this proposed model the presence of the extended conformation as the only well defined global conformer for AmB derivatives is taken as the indicator of their higher selective toxicity. This model successfully explains our results. To further test our model, we also investigated an AmB derivative whose selective toxicity has not been experimentally measured before. Our prediction for the selective toxicity of this compound can be tested in experiments to validate or invalidate the proposed model.
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Affiliation(s)
- H Resat
- Koç University, School of Arts and Sciences, Istinye Istanbul, Turkey.
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Borowski E. Novel approaches in the rational design of antifungal agents of low toxicity. FARMACO (SOCIETA CHIMICA ITALIANA : 1989) 2000; 55:206-8. [PMID: 10919084 DOI: 10.1016/s0014-827x(00)00024-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This paper presents an overview of studies on novel strategies for the rational design of antifungal agents of low toxicity and overcoming the multidrug resistance (MDR) of fungi. This goal was achieved both due to the introduction of a novel target, glucosamine-6-phosphate synthase, as well as to the recognition of molecular basis of selectivity of action of amphotericin B derivatives.
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Affiliation(s)
- E Borowski
- Department of Pharmaceutical Technology and Biochemistry, Technical University of Gdansk, Poland.
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30
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Baginski M, Gariboldi P, Bruni P, Borowski E. Conformational analysis of Amphotericin B. Biophys Chem 1997; 65:91-100. [PMID: 17029848 DOI: 10.1016/s0301-4622(96)02265-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/1996] [Revised: 12/03/1996] [Accepted: 12/05/1996] [Indexed: 10/18/2022]
Abstract
Within a theoretical approach to the problem of antifungal action of Amphotericin B (AmB), a conformational analysis of the neutral and zwitterionic form of this antibiotic in vacuo was performed by the MM2P and AM1 methods. The analysis was carried out with regard to the mutual orientation of the macrolidic and glycosidic fragments of the molecule, which is defined by the phi and psi steric angles. This orientation defines the overall shape of the molecule and is postulated to be important for the antifungal action of the drug. As a result of the MM2P calculations, phi, psi steric energy and population maps were prepared. Several conformers were found on these maps but only two of them (one each for the zwitterionic and the neutral forms of the antibiotic) were previously observed experimentally for isolated molecules. Our other calculated conformers were not observed experimentally but we propose that they may also appear in the AmB channel structure. The results of our conformational analysis were compared with experimental NMR data (nuclear Overhauser effects between selected hydrogen atoms) obtained previously. New structural information obtained for AmB in the present work will be useful for building a molecular model of AmB-target interactions as well as for designing new derivatives of AmB.
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Affiliation(s)
- M Baginski
- Department of Pharmaceutical Technology and Biochemistry, Technical University of Gdansk, Narutowicza St. 11/12, 80-952 Gdansk, Poland.
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Barwicz J, Tancrède P. The effect of aggregation state of amphotericin-B on its interactions with cholesterol- or ergosterol-containing phosphatidylcholine monolayers. Chem Phys Lipids 1997; 85:145-55. [PMID: 9138890 DOI: 10.1016/s0009-3084(96)02652-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Amphotericin B (AmB) is the most effective antibiotic used in the treatment of systemic fungal infections. It is generally thought that the activity of this drug results from its interaction with ergosterol, the main sterol of fungi membranes. However, AmB also interacts with cholesterol, the major sterol of mammal membranes, thus limiting the usefulness of this drug due to its relatively high toxicity. The aim of the present work is to study the molecular basis of the interactions of AmB with these sterols contained in a DOPC film by using the monolayer technique. Two different concentrations of the sterols in the film (13 and 30%) at an initial surface pressure of 30 mN/m were studied, which correspond to conditions found in various biological membranes. Four concentrations of AmB in the subphase, ranging from a molecularly dispersed to a highly aggregated state of the drug were studied. Our results show that the monomeric form of AmB interacts with the ergosterol containing film solely. On the other hand, when AmB is dispersed as a pre-micellar or as a highly aggregated state in the subphase, a very significant selectivity of its interactions between the two sterols is observed which is shown in our experimental results by a difference of 8 mN/m in the surface pressure when AmB interacts with ergosterol as compared to cholesterol. We show that the activity of AmB is most likely related to the micellar form of the antibiotic. In addition, we observe that upon increasing the amount of ergosterol in the film, the insertion of AmB is largely promoted, results that are discussed in terms of the molecular organization of the sterols within the monolayer film. We show that these results provide a better understanding of the action of AmB (activity/toxicity) at the membrane level.
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Affiliation(s)
- J Barwicz
- Département de chimie-biologie, Université du Québec à Trois-Rivières, Canada
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32
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Baginski M, Borowski E. Distribution of electrostatic potential around amphotericin B and its membrane targets. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0166-1280(96)04585-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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33
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Rudnitskikh AV, Tananova GV, Poroikov VV, Filimonov DA. A possible mechanism of probucol and cholesterol interaction. Pharm Chem J 1995. [DOI: 10.1007/bf02220538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mazerski J, Bolard J, Borowski E. Effect of the modifications of ionizable groups of amphotericin B on its ability to form complexes with sterols in hydroalcoholic media. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1236:170-6. [PMID: 7794947 DOI: 10.1016/0005-2736(95)00048-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The interaction of amphotericin B and some of its semisynthetic derivatives with cholesterol and ergosterol has been tested in 1:4 (v/v) ethanol/water mixture by circular dichroism and absorption spectroscopy. The effect of the chemical modification of the 'ionizable head' of the antibiotic, the pH of the medium, and the sterol/antibiotic ratio has been studied. The results obtained show that in the presence of the sterols, amphotericin B forms several spectroscopically different species. A high extent of polyene-sterol interaction is observed for: (i) amphotericin B in neutral or acidic media, (ii) esters and amides at neutral or alkaline media, (iii) N-acyl derivatives only in acidic medium. The extent of interaction at neutral pH is highly correlated with the biological activity of compounds tested. The implication of these findings on the nature of the forces responsible for the antibiotic-sterol interaction is discussed.
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Affiliation(s)
- J Mazerski
- Department of Pharmaceutical Technology and Biochemistry, Technical University of Gdańsk, Poland
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35
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Comparative analysis of the distribution of the molecular electrostatic potential for cholesterol and ergosterol. J Mol Struct 1994. [DOI: 10.1016/s0022-2860(10)80038-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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36
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Bagiński M, Bruni P, Borowski E. Comparative analysis of the distribution of the molecular electrostatic potential for cholesterol and ergosterol. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s0166-1280(09)80066-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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37
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Langlet J, Bergès J, Caillet J, Demaret JP. Theoretical study of the complexation of amphotericin B with sterols. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1191:79-93. [PMID: 8155687 DOI: 10.1016/0005-2736(94)90235-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The aim of this present work was the study of the intermolecular complexes between amphotericin B (AmB) and either cholesterol or ergosterol. In such complexes the intermolecular interaction energy mainly proceeds from both Van der Waals and H-bonding (via water molecules) forces. Our calculations have shown that the Van der Waals forces slightly favor the AmB-ergosterol complex. Several relative positions of the sterol with regard to AmB lead to energy minima: sterol may be either in contact with the AmB polar head or repelled towards the end of the macrolide ring. It appeared that the role played by some water molecules was to maintain the sterol close to the AmB polar head.
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Affiliation(s)
- J Langlet
- Université Pierre et Marie Curie, Paris, France
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38
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Bagiński M, Gariboldi P, Borowski E. The role of amphotericin B amino group basicity in its antifungal action. A theoretical approach. Biophys Chem 1994; 49:241-50. [PMID: 8018821 DOI: 10.1016/0301-4622(93)e0074-f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The role of basicity of the amine group of amphotericin B in the molecular mechanism of antifungal activity of this antibiotic has been investigated by AM1 and MNDO quantum chemistry methods. Calculations of proton affinity of the amine group, as a measure of its basicity, for appropriate models of free amphotericin B and its N-alkyl derivatives were carried out. These studies were preceded by a critical examination of the usefulness and reliability of both methods to predict the proton affinities of several aliphatic amines. It has been concluded that the diminution of protonability of the substituted amine group of amphotericin B correlates with the decrease of antifungal activity of the appropriate derivatives of antibiotic. It was experimentally demonstrated (A. Czerwiński et al., J. Antibiot. 44 (1991) 979) that the introduction of additional amine groups in such a derivative restores antifungal activity of the compound. In our studies it was evidenced, using theoretical methods, that the proton affinity of this additional amine group is similar to that in free amphotericin B.
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Affiliation(s)
- M Bagiński
- Department of Pharmaceutical Technology and Biochemistry, Technical University of Gdańsk, Poland
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Abstract
The structures of amphotericin B-cholesterol complex that forms a channel in a lipid membrane were analysed by molecular mechanics calculations. The symmetric complex consisting of eight rigid antibiotic and cholesterol molecules was considered. The presence of a continuous set of low-energy states of the complex with different values of the channel diameter was shown. These states are characterized by significant tilt of the amphotericin planes to the radial axis of the channel and by strong interaction between the charged ammonium and carboxyl groups of the antibiotic. Changes of the channel diameter may result in changes in pore permeability.
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Affiliation(s)
- V E Khutorsky
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
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40
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Gruda I, Milette D, Brother M, Kobayashi GS, Medoff G, Brajtburg J. Structure-activity study of inhibition of amphotericin B (Fungizone) binding to sterols, toxicity to cells, and lethality to mice by esters of sucrose. Antimicrob Agents Chemother 1991; 35:24-8. [PMID: 2014979 PMCID: PMC244936 DOI: 10.1128/aac.35.1.24] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The effects of four monoesters of sucrose with different acyl chain lengths (palmitate, C16; myristate, C14; laurate, C12; and caprate, C10) on the aggregation state of amphotericin B (AmB), its binding to cholesterol and ergosterol, its toxicity to cells, and its lethality to mice were determined. In solution, all four of these esters inhibited AmB binding to cholesterol more than to ergosterol; this effect correlated with the ester-induced shift from the mainly aggregated form of AmB to the mainly monomeric form. In experiments with cells, the esters inhibited the toxicity of AmB to mouse erythrocytes and cultured mouse fibroblast L-929 cells more than its toxicity to Candida albicans cells. When injected intravenously with AmB, these esters decreased AmB lethality to mice. In all of these assays, the ester with the shortest chain length (caprate) was much less potent than the other three esters. Our results indicate a correlation between in vitro and in vivo assays and suggest that the in vitro and in vivo selectivity of AmB may be enhanced by surface-active agents which modulate the aggregation state of AmB.
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Affiliation(s)
- I Gruda
- Département de Chimie-Biologie, Université du Québec à Trois-Rivières, Canada
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Polak A, Hartman PG. Antifungal chemotherapy--are we winning? PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1991; 37:181-269. [PMID: 1763183 DOI: 10.1007/978-3-0348-7139-6_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- A Polak
- F. Hoffmann-La Roche Ltd, Basel, Switzerland
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42
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Leach AR, Prout K. Automated conformational analysis: Directed conformational search using the A* algorithm. J Comput Chem 1990. [DOI: 10.1002/jcc.540111012] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Brajtburg J, Powderly WG, Kobayashi GS, Medoff G. Amphotericin B: current understanding of mechanisms of action. Antimicrob Agents Chemother 1990; 34:183-8. [PMID: 2183713 PMCID: PMC171553 DOI: 10.1128/aac.34.2.183] [Citation(s) in RCA: 350] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- J Brajtburg
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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