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Ciesielski F, Griffin DC, Loraine J, Rittig M, Delves-Broughton J, Bonev BB. Recognition of Membrane Sterols by Polyene Antifungals Amphotericin B and Natamycin, A (13)C MAS NMR Study. Front Cell Dev Biol 2016; 4:57. [PMID: 27379235 PMCID: PMC4911417 DOI: 10.3389/fcell.2016.00057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/30/2016] [Indexed: 01/30/2023] Open
Abstract
The molecular action of polyene macrolides with antifungal activity, amphotericin B and natamycin, involves recognition of sterols in membranes. Physicochemical and functional studies have contributed details to understanding the interactions between amphotericin B and ergosterol and, to a lesser extent, with cholesterol. Fewer molecular details are available on interactions between natamycin with sterols. We use solid state (13)C MAS NMR to characterize the impact of amphotericin B and natamycin on mixed lipid membranes of DOPC/cholesterol or DOPC/ergosterol. In cholesterol-containing membranes, amphotericin B addition resulted in marked increase in both DOPC and cholesterol (13)C MAS NMR linewidth, reflecting membrane insertion and cooperative perturbation of the bilayer. By contrast, natamycin affects little either DOPC or cholesterol linewidth but attenuates cholesterol resonance intensity preferentially for sterol core with lesser impact on the chain. Ergosterol resonances, attenuated by amphotericin B, reveal specific interactions in the sterol core and chain base. Natamycin addition selectively augmented ergosterol resonances from sterol core ring one and, at the same time, from the end of the chain. This puts forward an interaction model similar to the head-to-tail model for amphotericin B/ergosterol pairing but with docking on opposite sterol faces. Low toxicity of natamycin is attributed to selective, non-cooperative sterol engagement compared to cooperative membrane perturbation by amphotericin B.
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Affiliation(s)
- Filip Ciesielski
- School of Life Sciences, Queen's Medical Centre, University of Nottingham Nottingham, UK
| | - David C Griffin
- School of Life Sciences, Queen's Medical Centre, University of Nottingham Nottingham, UK
| | - Jessica Loraine
- School of Life Sciences, Queen's Medical Centre, University of Nottingham Nottingham, UK
| | - Michael Rittig
- School of Life Sciences, Queen's Medical Centre, University of Nottingham Nottingham, UK
| | | | - Boyan B Bonev
- School of Life Sciences, Queen's Medical Centre, University of Nottingham Nottingham, UK
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Clifton LA, Ciesielski F, Skoda MWA, Paracini N, Holt SA, Lakey JH. The Effect of Lipopolysaccharide Core Oligosaccharide Size on the Electrostatic Binding of Antimicrobial Proteins to Models of the Gram Negative Bacterial Outer Membrane. Langmuir 2016; 32:3485-94. [PMID: 27003358 PMCID: PMC4854487 DOI: 10.1021/acs.langmuir.6b00240] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/28/2016] [Indexed: 05/23/2023]
Abstract
Understanding the electrostatic interactions between bacterial membranes and exogenous proteins is crucial to designing effective antimicrobial agents against Gram-negative bacteria. Here we study, using neutron reflecometry under multiple isotopic contrast conditions, the role of the uncharged sugar groups in the outer core region of lipopolysaccharide (LPS) in protecting the phosphate-rich inner core region from electrostatic interactions with antimicrobial proteins. Models of the asymmetric Gram negative outer membrane on silicon were prepared with phopshatidylcholine (PC) in the inner leaflet (closest to the silicon), whereas rough LPS was used to form the outer leaflet (facing the bulk solution). We show how salt concentration can be used to reversibly alter the binding affinity of a protein antibiotic colicin N (ColN) to the anionic LPS confirming that the interaction is electrostatic in nature. By examining the interaction of ColN with two rough LPS types with different-sized core oligosaccharide regions we demonstrate the role of uncharged sugars in blocking short-range electrostatic interactions between the cationic antibiotics and the vulnerable anionic phosphate groups.
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Affiliation(s)
- Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory , Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, United Kingdom
| | - Filip Ciesielski
- Department of Plant Sciences, University of Oxford , Oxford, OX1 3RB, United Kingdom
| | - Maximilian W A Skoda
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory , Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, United Kingdom
| | - Nicolò Paracini
- Institute for Cell and Molecular Biosciences, Newcastle University , Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
| | - Stephen A Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation , Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, Newcastle University , Framlington Place, Newcastle upon Tyne, NE2 4HH, United Kingdom
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Clifton LA, Skoda MA, Le Brun A, Ciesielski F, Kuzmenko I, Holt SA, Lakey JH. Effect of divalent cation removal on the structure of gram-negative bacterial outer membrane models. Langmuir 2015; 31:404-12. [PMID: 25489959 PMCID: PMC4295546 DOI: 10.1021/la504407v] [Citation(s) in RCA: 216] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 12/09/2014] [Indexed: 05/18/2023]
Abstract
The Gram-negative bacterial outer membrane (GNB-OM) is asymmetric in its lipid composition with a phospholipid-rich inner leaflet and an outer leaflet predominantly composed of lipopolysaccharides (LPS). LPS are polyanionic molecules, with numerous phosphate groups present in the lipid A and core oligosaccharide regions. The repulsive forces due to accumulation of the negative charges are screened and bridged by the divalent cations (Mg(2+) and Ca(2+)) that are known to be crucial for the integrity of the bacterial OM. Indeed, chelation of divalent cations is a well-established method to permeabilize Gram-negative bacteria such as Escherichia coli. Here, we use X-ray and neutron reflectivity (XRR and NR, respectively) techniques to examine the role of calcium ions in the stability of a model GNB-OM. Using XRR we show that Ca(2+) binds to the core region of the rough mutant LPS (RaLPS) films, producing more ordered structures in comparison to divalent cation free monolayers. Using recently developed solid-supported models of the GNB-OM, we study the effect of calcium removal on the asymmetry of DPPC:RaLPS bilayers. We show that without the charge screening effect of divalent cations, the LPS is forced to overcome the thermodynamically unfavorable energy barrier and flip across the hydrophobic bilayer to minimize the repulsive electrostatic forces, resulting in about 20% mixing of LPS and DPPC between the inner and outer bilayer leaflets. These results reveal for the first time the molecular details behind the well-known mechanism of outer membrane stabilization by divalent cations. This confirms the relevance of the asymmetric models for future studies of outer membrane stability and antibiotic penetration.
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Affiliation(s)
- Luke A. Clifton
- ISIS
Pulsed Neutron and Muon Source, Science and Technology Facilities
Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, United Kingdom
- E-mail:
| | - Maximilian
W. A. Skoda
- ISIS
Pulsed Neutron and Muon Source, Science and Technology Facilities
Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, United Kingdom
| | - Anton
P. Le Brun
- Bragg
Institute, Australian Nuclear Science and
Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Filip Ciesielski
- ISIS
Pulsed Neutron and Muon Source, Science and Technology Facilities
Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, United Kingdom
| | - Ivan Kuzmenko
- Advanced
Photon Source , Argonne National Laboratories, Argonne, Illinois 60439, United States
| | - Stephen A. Holt
- Bragg
Institute, Australian Nuclear Science and
Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Jeremy H. Lakey
- Institute
for Cell and Molecular Biosciences, Newcastle
University, Framlington
Place, Newcastle upon Tyne NE2 4HH, United Kingdom
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Ciesielski F, Griffin DC, Rittig M, Moriyón I, Bonev BB. Interactions of lipopolysaccharide with lipid membranes, raft models — A solid state NMR study. Biochimica et Biophysica Acta (BBA) - Biomembranes 2013; 1828:1731-42. [DOI: 10.1016/j.bbamem.2013.03.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/08/2013] [Accepted: 03/28/2013] [Indexed: 01/09/2023]
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Ciesielski F, Davis B, Rittig M, Bonev BB, O'Shea P. Receptor-independent interaction of bacterial lipopolysaccharide with lipid and lymphocyte membranes; the role of cholesterol. PLoS One 2012; 7:e38677. [PMID: 22685597 PMCID: PMC3369841 DOI: 10.1371/journal.pone.0038677] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 05/10/2012] [Indexed: 01/18/2023] Open
Abstract
Lipopolysaccharide (LPS) is a major constituent of bacterial outer membranes where it makes up the bulk of the outer leaflet and plays a key role as determinant of bacterial interactions with the host. Membrane-free LPS is known to activate T-lymphocytes through interactions with Toll-like receptor 4 via multiprotein complexes. In the present study, we investigate the role of cholesterol and membrane heterogeneities as facilitators of receptor-independent LPS binding and insertion, which underpin bacterial interactions with the host in symbiosis, pathogenesis and cell invasion. We use fluorescence spectroscopy to investigate the interactions of membrane-free LPS from intestinal Gram-negative organisms with cholesterol-containing model membranes and with T-lymphocytes. LPS preparations from Klebsiella pneumoniae and Salmonella enterica were found to bind preferentially to mixed lipid membranes by comparison to pure PC bilayers. The same was observed for LPS from the symbiote Escherichia coli but with an order of magnitude higher dissociation constant. Insertion of LPS into model membranes confirmed the preference for sphimgomyelin/cholesterol-containing systems. LPS insertion into Jurkat T-lymphocyte membranes reveals that they have a significantly greater LPS-binding capacity by comparison to methyl-β-cyclodextrin cholesterol-depleted lymphocyte membranes, albeit at slightly lower binding rates.
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Affiliation(s)
- Filip Ciesielski
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Benjamin Davis
- School of Biology, University of Nottingham, Nottingham, United Kingdom
| | - Michael Rittig
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Boyan B. Bonev
- School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom
- * E-mail: (BBB); (PS)
| | - Paul O'Shea
- School of Biology, University of Nottingham, Nottingham, United Kingdom
- * E-mail: (BBB); (PS)
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Zorin V, Ciesielski F, Griffin DC, Rittig M, Bonev BB. Heteronuclear chemical shift correlation and J-resolved MAS NMR spectroscopy of lipid membranes. Magn Reson Chem 2010; 48:925-934. [PMID: 20941803 DOI: 10.1002/mrc.2690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Direct observation of J-couplings remains a challenge in high-resolution solid-state NMR. In some cases, it is possible to use Lee-Goldburg (LG) homonuclear decoupling during rare spin observation in MAS NMR correlation spectroscopy of lipid membranes to obtain J-resolved spectra in the direct dimension. In one simple implementation, a wide line separation-type (13)C-(1)H HETCOR can provide high-resolution (1)H/(13)C spectra, which are J-resolved in both dimensions. Coupling constants, (1)J(HC), obtained from (1)H doublets, can be compared with scaled (1)J(θ)(CH)-values obtained from the (13)C multiplets to assess the LG efficiency and scaling factor. The use of homonuclear decoupling during proton evolution, LG-HETCOR-LG, can provide J-values, at least in the rare spin dimension, and allows measurements in less mobile membrane environments. The LG-decoupled spectroscopic approach is demonstrated on pure dioleoylphosphatidylcholine (DOPC) membranes and used to investigate lipid mixtures of DOPC/cholesterol and DOPC/cholesterol/sphingomyelin.
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Sato Y, Hourai S, Antony P, Molnar F, Huet T, Ciesielski F, Segueiro R, Rodrigues L, Mourino A, Rochel N, Moras D. Development of superagonist ligands for the vitamin D nuclear receptor, AMCR277A, -B and 2MeAMCR. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308089629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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