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Lee TH, Charchar P, Separovic F, Reid GE, Yarovsky I, Aguilar MI. The intricate link between membrane lipid structure and composition and membrane structural properties in bacterial membranes. Chem Sci 2024; 15:3408-3427. [PMID: 38455013 PMCID: PMC10915831 DOI: 10.1039/d3sc04523d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024] Open
Abstract
It is now evident that the cell manipulates lipid composition to regulate different processes such as membrane protein insertion, assembly and function. Moreover, changes in membrane structure and properties, lipid homeostasis during growth and differentiation with associated changes in cell size and shape, and responses to external stress have been related to drug resistance across mammalian species and a range of microorganisms. While it is well known that the biomembrane is a fluid self-assembled nanostructure, the link between the lipid components and the structural properties of the lipid bilayer are not well understood. This perspective aims to address this topic with a view to a more detailed understanding of the factors that regulate bilayer structure and flexibility. We describe a selection of recent studies that address the dynamic nature of bacterial lipid diversity and membrane properties in response to stress conditions. This emerging area has important implications for a broad range of cellular processes and may open new avenues of drug design for selective cell targeting.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
| | - Patrick Charchar
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
| | - Gavin E Reid
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne VIC 3010 Australia
- Department of Biochemistry and Pharmacology, University of Melbourne Parkville VIC 3010 Australia
| | - Irene Yarovsky
- School of Engineering, RMIT University Melbourne Victoria 3001 Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University Clayton VIC 3800 Australia
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2
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Sani MA, Le Brun AP, Rajput S, Attard T, Separovic F. The membrane activity of the antimicrobial peptide caerin 1.1 is pH dependent. Biophys J 2023; 122:1058-1067. [PMID: 36680343 PMCID: PMC10111263 DOI: 10.1016/j.bpj.2023.01.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 12/09/2022] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
Antimicrobial peptides are an important class of membrane-active peptides that can provide alternatives or complements to classic antibiotics. Among the many classes of AMPs, the histidine-rich family is of particular interest since they may induce pH-sensitive interactions with cell membranes. The AMP caerin 1.1 (Cae-1), from Australian tree frogs, has three histidine residues, and thus we studied the pH dependence of its interactions with model cell membranes. Using NMR spectroscopy and molecular dynamics simulations, we showed that Cae-1 induced greater perturbation of the lipid dynamics and water penetrations within the membrane interior in an acidic environment compared with physiological conditions. Using 31P solid-state NMR, the packing, chemical environment, and dynamics of the lipid headgroup were monitored. 2H solid-state NMR showed that Cae-1 ordered the acyl chains of the hydrophobic core of the bilayer. These results supported the molecular dynamics data, which showed that Cae-1 was mainly inserted within the lipid bilayer for both neutral and negatively charged membranes, with the charged residues pulling the water and phosphate groups inward. This could be an early step in the mechanism of membrane disruption by histidine-rich antimicrobial peptides and indicated that Cae-1 acts via a transmembrane mechanism in bilayers of neutral and anionic phospholipid membranes, especially in acidic conditions.
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Affiliation(s)
- Marc-Antoine Sani
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia.
| | - Anton P Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Kirrawee, New South Wales, Australia
| | - Sunnia Rajput
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Troy Attard
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Frances Separovic
- Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia; School of Chemistry, University of Melbourne, Melbourne, Victoria, Australia.
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3
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Menon AP, Dong W, Lee TH, Aguilar MI, Duan M, Kapoor S. Mutually Exclusive Interactions of Rifabutin with Spatially Distinct Mycobacterial Cell Envelope Membrane Layers Offer Insights into Membrane-Centric Therapy of Infectious Diseases. ACS BIO & MED CHEM AU 2022; 2:395-408. [PMID: 35996474 PMCID: PMC9389580 DOI: 10.1021/acsbiomedchemau.2c00010] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anjana P. Menon
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Wanqian Dong
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Tzong-Hsien Lee
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Marie-Isabel Aguilar
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Department of Biochemistry & Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Mojie Duan
- Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Shobhna Kapoor
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
- IITB-Monash Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima 739-8528, Japan
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Abstract
AbstractThe complex composition of bacterial membranes has a significant impact on the understanding of pathogen function and their development towards antibiotic resistance. In addition to the inherent complexity and biosafety risks of studying biological pathogen membranes, the continual rise of antibiotic resistance and its significant economical and clinical consequences has motivated the development of numerous in vitro model membrane systems with tuneable compositions, geometries, and sizes. Approaches discussed in this review include liposomes, solid-supported bilayers, and computational simulations which have been used to explore various processes including drug-membrane interactions, lipid-protein interactions, host–pathogen interactions, and structure-induced bacterial pathogenesis. The advantages, limitations, and applicable analytical tools of all architectures are summarised with a perspective for future research efforts in architectural improvement and elucidation of resistance development strategies and membrane-targeting antibiotic mechanisms.
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Kumar K, Sebastiao M, Arnold AA, Bourgault S, Warschawski DE, Marcotte I. IN SITU SOLID-STATE NMR STUDY OF ANTIMICROBIAL PEPTIDE INTERACTIONs WITH ERYTHROCYTE MEMBRANES. Biophys J 2022; 121:1512-1524. [PMID: 35278426 PMCID: PMC9072582 DOI: 10.1016/j.bpj.2022.03.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/01/2022] [Accepted: 03/07/2022] [Indexed: 11/02/2022] Open
Abstract
Antimicrobial peptides are promising therapeutic agents to mitigate the global rise of antibiotic resistance. They generally act by perturbing the bacterial cell membrane and are thus less likely to induce resistance. Because they are membrane-active molecules, it is critical to verify and understand their potential action toward eukaryotic cells to help design effective and safe drugs. In this work, we studied the interaction of two antimicrobial peptides, aurein 1.2 and caerin 1.1, with red blood cell (RBC) membranes using in situ 31P and 2H solid-state NMR (SS-NMR). We established a protocol to integrate up to 25% of deuterated fatty acids in the membranes of ghosts, which are obtained when hemoglobin is removed from RBCs. Fatty acid incorporation and the integrity of the lipid bilayer were confirmed by SS-NMR and fluorescence confocal microscopy. Leakage assays were performed to assess the lytic power of the antimicrobial peptides. The in situ perturbation of the ghost membranes by aurein 1.2 and caerin 1.1 revealed by 31P and 2H SS-NMR is consistent with membrane perturbation through a carpet mechanism for aurein 1.2, whereas caerin 1.1 acts on RBCs via pore formation. These results are compatible with fluorescence microscopy images of the ghosts. The peptides interact with eukaryotic membranes following similar mechanisms that take place in bacteria, highlighting the importance of hydrophobicity when determining such interactions. Our work bridges model membranes and in vitro studies and provides an analytical toolbox to assess drug toxicity toward eukaryotic cells.
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Multi-Omic Analysis to Characterize Metabolic Adaptation of the E. coli Lipidome in Response to Environmental Stress. Metabolites 2022; 12:metabo12020171. [PMID: 35208246 PMCID: PMC8880424 DOI: 10.3390/metabo12020171] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 12/17/2022] Open
Abstract
As an adaptive survival response to exogenous stress, bacteria undergo dynamic remodelling of their lipid metabolism pathways to alter the composition of their cellular membranes. Here, using Escherichia coli as a well characterised model system, we report the development and application of a ‘multi-omics’ strategy for comprehensive quantitative analysis of the temporal changes in the lipidome and proteome profiles that occur under exponential growth phase versus stationary growth phase conditions i.e., nutrient depletion stress. Lipidome analysis performed using ‘shotgun’ direct infusion-based ultra-high resolution accurate mass spectrometry revealed a quantitative decrease in total lipid content under stationary growth phase conditions, along with a significant increase in the mol% composition of total cardiolipin, and an increase in ‘odd-numbered’ acyl-chain length containing glycerophospholipids. The inclusion of field asymmetry ion mobility spectrometry was shown to enable the enrichment and improved depth of coverage of low-abundance cardiolipins, while ultraviolet photodissociation-tandem mass spectrometry facilitated more complete lipid structural characterisation compared with conventional collision-induced dissociation, including unambiguous assignment of the odd-numbered acyl-chains as containing cyclopropyl modifications. Proteome analysis using data-dependent acquisition nano-liquid chromatography mass spectrometry and tandem mass spectrometry analysis identified 83% of the predicted E. coli lipid metabolism enzymes, which enabled the temporal dependence associated with the expression of key enzymes responsible for the observed adaptive lipid metabolism to be determined, including those involved in phospholipid metabolism (e.g., ClsB and Cfa), fatty acid synthesis (e.g., FabH) and degradation (e.g., FadA/B,D,E,I,J and M), and proteins involved in the oxidative stress response resulting from the generation of reactive oxygen species during β-oxidation or lipid degradation.
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Separovic F, Hofferek V, Duff AP, McConville MJ, Sani MA. In-cell DNP NMR reveals multiple targeting effect of antimicrobial peptide. J Struct Biol X 2022; 6:100074. [PMID: 36147732 PMCID: PMC9486116 DOI: 10.1016/j.yjsbx.2022.100074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/25/2022] [Accepted: 08/29/2022] [Indexed: 11/28/2022] Open
Abstract
DNP NMR allowed simultaneous monitoring of lipids, proteins and nucleic acids of E. coli cells. The bacterial stress response against an antimicrobial peptide was measured in situ. The antimicrobial peptide maculatin 1.1 significantly compacted nucleic acids in bacteria. Maculatin 1.1 prevented salt bridges forming between membrane lipids.
Dynamic nuclear polarization NMR spectroscopy was used to investigate the effect of the antimicrobial peptide (AMP) maculatin 1.1 on E. coli cells. The enhanced 15N NMR signals from nucleic acids, proteins and lipids identified a number of unanticipated physiological responses to peptide stress, revealing that membrane-active AMPs can have a multi-target impact on E. coli cells. DNP-enhanced 15N-observed 31P-dephased REDOR NMR allowed monitoring how Mac1 induced DNA condensation and prevented intermolecular salt bridges between the main E. coli lipid phosphatidylethanolamine (PE) molecules. The latter was supported by similar results obtained using E. coli PE lipid systems. Overall, the ability to monitor the action of antimicrobial peptides in situ will provide greater insight into their mode of action.
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Affiliation(s)
- Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Vinzenz Hofferek
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Anthony P. Duff
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Kirrawee DC, NSW 2232, Australia
| | - Malcom J. McConville
- Department of Biochemistry and Molecular Biology, Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC 3010, Australia
- Corresponding author.
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Laydevant F, Mahabadi M, Llido P, Bourgouin JP, Caron L, Arnold AA, Marcotte I, Warschawski DE. Growth-phase dependence of bacterial membrane lipid profile and labeling for in-cell solid-state NMR applications. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1864:183819. [PMID: 34800428 DOI: 10.1016/j.bbamem.2021.183819] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 10/31/2021] [Accepted: 11/05/2021] [Indexed: 10/19/2022]
Abstract
Cell labeling is a preliminary step in multiple biophysical approaches, including the solid-state nuclear magnetic resonance (NMR) study of bacteria in vivo. Deuterium solid-state NMR has been used in the past years to probe bacterial membranes and their interactions with antimicrobial peptides, following a standard labeling protocol. Recent results from our laboratory on a slow-growing bacterium has shown the need to optimize this protocol, especially the bacterial growth time before harvest and the concentration of exogenous labeled fatty acids to be used for both Escherichia coli and Bacillus subtilis. It is also essential for the protocol to remain harmless to cells while providing optimal labeling. We have therefore developed a fast and facile approach to monitor the lipid composition of bacterial membranes under various growth conditions, combining solution 31P NMR and GCMS. Using this approach, the optimized labeling conditions of Escherichia coli and Bacillus subtilis with deuterated palmitic acid were determined. Our results show a modification of B. subtilis phospholipid profile as a function of the growth stage, as opposed to E. coli. Our protocol recommends low concentrations of exogenous palmitic acid in the growth medium, and bacteria harvest after the exponential phase.
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Affiliation(s)
- Florent Laydevant
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Mahsa Mahabadi
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Pierre Llido
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Jean-Philippe Bourgouin
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Laurence Caron
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Alexandre A Arnold
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.
| | - Dror E Warschawski
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada; Laboratoire des Biomolécules, LBM, CNRS UMR 7203, Sorbonne Université, École normale supérieure, PSL University, 75005 Paris, France.
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Lipid domain formation and non-lamellar structures associated with varied lysylphosphatidylglycerol analogue content in a model Staphylococcal plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183571. [PMID: 33561475 DOI: 10.1016/j.bbamem.2021.183571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 01/02/2023]
Abstract
Dipalmitoyl-3-aza-dehydroxy-lysylphosphatidylglycerol (DP3adLPG), is a chemically stable synthetic analogue of the bacterial lipid lysylphosphatidylglycerol (LPG), designed as a substitute for the notoriously labile native lipid in biophysical investigations. In Staphylococcus aureus, LPG is known to play a role in resistance to antibiotics by altering membrane charge properties in response to environmental stress, but little is known about how LPG influences other bilayer physicochemical properties or lateral organisation, through the formation of complexes with lipids such as phosphatidylglycerol (PG). In this study we have investigated the different phases formed by biomimetic mixtures of 3adLPG and PG in different thermotropic states, using neutron diffraction and electron microscopy. In a DPPG/DP3adLPG 70:30 mol% mixture, two distinct lamellar phases were observed below the lipid melting transition: Lβ' 1 and Lβ' 2 with respective periodicities of 82 and 62 Å. Increasing the proportion of DP3adLPG to mimic the effects of environmental stress led to the disappearance of the Lβ' 1 phase and the formation of an inverse hexagonal phase. The compositions of these different phases were identified by investigating the thermotropic properties of the two mixtures, and probing their interaction with the antimicrobial peptide magainin 2 F5W. We propose that the observed polymorphism results from the preferential formation of either triplet PG-3adLPG-PG, or paired PG-3adLPG complexes, dependent upon the mixing proportions of the two lipids. The relevance of these findings to the role native LPG in S. aureus, are discussed with respect to their influence on antibiotic resistance and lateral membrane organisation.
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