1
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Oludiran A, Malik A, Zourou AC, Wu Y, Gross SP, Siryapon A, Poudel A, Alleyne K, Adams S, Courson DS, Cotten ML, Purcell EB. Host-defense piscidin peptides as antibiotic adjuvants against Clostridioides difficile. PLoS One 2024; 19:e0295627. [PMID: 38252641 PMCID: PMC10802969 DOI: 10.1371/journal.pone.0295627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/26/2023] [Indexed: 01/24/2024] Open
Abstract
The spore-forming intestinal pathogen Clostridioides difficile causes multidrug resistant infection with a high rate of recurrence after treatment. Piscidins 1 (p1) and 3 (p3), cationic host defense peptides with micromolar cytotoxicity against C. difficile, sensitize C. difficile to clinically relevant antibiotics tested at sublethal concentrations. Both peptides bind to Cu2+ using an amino terminal copper and nickel binding motif. Here, we investigate the two peptides in the apo and holo states as antibiotic adjuvants against an epidemic strain of C. difficile. We find that the presence of the peptides leads to lower doses of metronidazole, vancomycin, and fidaxomicin to kill C. difficile. The activity of metronidazole, which targets DNA, is enhanced by a factor of 32 when combined with p3, previously shown to bind and condense DNA. Conversely, the activity of vancomycin, which acts at bacterial cell walls, is enhanced 64-fold when combined with membrane-active p1-Cu2+. As shown through microscopy monitoring the permeabilization of membranes of C. difficile cells and vesicle mimics of their membranes, the adjuvant effect of p1 and p3 in the apo and holo states is consistent with a mechanism of action where the peptides enable greater antibiotic penetration through the cell membrane to increase their bioavailability. The variations in effects obtained with the different forms of the peptides reveal that while all piscidins generally sensitize C. difficile to antibiotics, co-treatments can be optimized in accordance with the underlying mechanism of action of the peptides and antibiotics. Overall, this study highlights the potential of antimicrobial peptides as antibiotic adjuvants to increase the lethality of currently approved antibiotic dosages, reducing the risk of incomplete treatments and ensuing drug resistance.
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Affiliation(s)
- Adenrele Oludiran
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Areej Malik
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
- Biomedical Sciences Program, Old Dominion University, Norfolk, Virginia, United States of America
| | - Andriana C. Zourou
- Department of Applied Science, William & Mary, Williamsburg, Virginia, United States of America
| | - Yonghan Wu
- Irvine Department of Physics and Astronomy, University of California, Los Angeles, California, United States of America
| | - Steven P. Gross
- Ivrine Department of Developmental and Cell Biology, University of California, Los Angeles, California, United States of America
| | - Albert Siryapon
- Irvine Department of Physics and Astronomy, University of California, Los Angeles, California, United States of America
| | - Asia Poudel
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Kwincy Alleyne
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Savion Adams
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - David S. Courson
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
| | - Myriam L. Cotten
- Department of Applied Science, William & Mary, Williamsburg, Virginia, United States of America
| | - Erin B. Purcell
- Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America
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2
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Liu F, Greenwood AI, Xiong Y, Miceli RT, Fu R, Anderson KW, McCallum SA, Mihailescu M, Gross R, Cotten ML. Host Defense Peptide Piscidin and Yeast-Derived Glycolipid Exhibit Synergistic Antimicrobial Action through Concerted Interactions with Membranes. JACS AU 2023; 3:3345-3365. [PMID: 38155643 PMCID: PMC10751773 DOI: 10.1021/jacsau.3c00506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 12/30/2023]
Abstract
Developing new antimicrobials as alternatives to conventional antibiotics has become an urgent race to eradicate drug-resistant bacteria and to save human lives. Conventionally, antimicrobial molecules are studied independently even though they can be cosecreted in vivo. In this research, we investigate two classes of naturally derived antimicrobials: sophorolipid (SL) esters as modified yeast-derived glycolipid biosurfactants that feature high biocompatibility and low production cost; piscidins, which are host defense peptides (HDPs) from fish. While HDPs such as piscidins target the membrane of pathogens, and thus result in low incidence of resistance, SLs are not well understood on a mechanistic level. Here, we demonstrate that combining SL-hexyl ester (SL-HE) with subinhibitory concentration of piscidins 1 (P1) and 3 (P3) stimulates strong antimicrobial synergy, potentiating a promising therapeutic window. Permeabilization assays and biophysical studies employing circular dichroism, NMR, mass spectrometry, and X-ray diffraction are performed to investigate the mechanism underlying this powerful synergy. We reveal four key mechanistic features underlying the synergistic action: (1) P1/3 binds to SL-HE aggregates, becoming α-helical; (2) piscidin-glycolipid assemblies synergistically accumulate on membranes; (3) SL-HE used alone or bound to P1/3 associates with phospholipid bilayers where it induces defects; (4) piscidin-glycolipid complexes disrupt the bilayer structure more dramatically and differently than either compound alone, with phase separation occurring when both agents are present. Overall, dramatic enhancement in antimicrobial activity is associated with the use of two membrane-active agents, with the glycolipid playing the roles of prefolding the peptide, coordinating the delivery of both agents to bacterial surfaces, recruiting the peptide to the pathogenic membranes, and supporting membrane disruption by the peptide. Given that SLs are ubiquitously and safely used in consumer products, the SL/peptide formulation engineered and mechanistically characterized in this study could represent fertile ground to develop novel synergistic agents against drug-resistant bacteria.
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Affiliation(s)
- Fei Liu
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Alexander I. Greenwood
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Yawei Xiong
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
| | - Rebecca T. Miceli
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Riqiang Fu
- Center
of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Kyle W. Anderson
- National
Institute of Standards and Technology, Rockville, Maryland 20850, United States
| | - Scott A. McCallum
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mihaela Mihailescu
- Institute
for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States
| | - Richard Gross
- Department
of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Myriam L. Cotten
- Department
of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
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3
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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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4
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Nguyen TN, Teimouri H, Medvedeva A, Kolomeisky AB. Cooperativity in Bacterial Membrane Association Controls the Synergistic Activities of Antimicrobial Peptides. J Phys Chem B 2022; 126:7365-7372. [PMID: 36108158 DOI: 10.1021/acs.jpcb.2c05345] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Antimicrobial peptides (AMPs), or defence peptides, are compounds naturally produced during immune responses of living organisms against bacterial infections that are currently actively considered as promising alternatives to antibiotics. Recent experimental studies uncovered that in many situations, combinations of different AMPs are much more successful in eliminating the bacterial pathogens than single peptide species. However, the microscopic origin of such synergistic activities remains not fully understood. We present and investigate a possible mechanism of synergy between AMPs. It is based on the idea that due to inter-molecular interactions, the presence of an AMP of one type stimulates the association of an AMP of another type, and this accelerates the overall association to the membrane, eventually killing the bacteria. This approach allows us to fully quantify the synergistic activities of AMPs, and it is successfully applied for several experimental systems. It is found that strong cooperativity can be achieved for relatively weak inter-molecular interactions, suggesting that the application of combinations of AMPs can be further rationally optimized to make it a powerful antibacterial treatment.
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Affiliation(s)
- Thao N Nguyen
- Department of Chemistry, Rice University, Houston, Texas 77005, United States.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States.,Applied Physics Program, Rice University, Houston, Texas 77005, United States
| | - Hamid Teimouri
- Department of Chemistry, Rice University, Houston, Texas 77005, United States.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Angela Medvedeva
- Department of Chemistry, Rice University, Houston, Texas 77005, United States.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Anatoly B Kolomeisky
- Department of Chemistry, Rice University, Houston, Texas 77005, United States.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States.,Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States.,Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
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5
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Lin B, Hung A, Li R, Barlow A, Singleton W, Matthyssen T, Sani MA, Hossain MA, Wade JD, O'Brien-Simpson NM, Li W. Systematic comparison of activity and mechanism of antimicrobial peptides against nosocomial pathogens. Eur J Med Chem 2022; 231:114135. [DOI: 10.1016/j.ejmech.2022.114135] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 12/20/2022]
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6
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Yasuhara K, Tsukamoto M, Kikuchi JI, Kuroda K. An Antimicrobial Peptide-Mimetic Methacrylate Random Copolymer Induces Domain Formation in a Model Bacterial Membrane. J Membr Biol 2022; 255:513-521. [PMID: 35182193 DOI: 10.1007/s00232-022-00220-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 02/04/2022] [Indexed: 10/19/2022]
Abstract
To address the emerging issue of drug-resistant bacteria, membrane-active synthetic polymers have been designed and developed to mimic host-defense antimicrobial peptides (AMPs) as antibiotic alternatives. In this study, we investigated the domain formation induced by synthetic polymer mimics of AMPs using model membranes to elucidate the biophysical principles that govern their membrane-active mechanisms. To that end, lipid vesicles mimicking Escherichia coli (E. coli) membrane were prepared using an 8:2 (molar ratio) mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), sodium salt (POPG). Our studies using differential scanning calorimetry (DSC) and fluorescence microscopy indicated that cationic amphiphilic methacrylate random copolymers induced the phase separation to form POPE- or POPG-rich domains. A rhodamine-labeled polymer also showed the binding to separated domains in the membrane. Based on these results, we propose the mechanism that the copolymers induce domain formation by clustering of anionic POPG lipids similar to natural AMPs. In addition, the time-course of polymer binding to the GUV membrane was sigmoidal, suggesting the positive feedback loop in the membrane binding. We also hypothesize that this cooperative binding of the polymer is driven by the domain formation. This study demonstrates the potential of the amphiphilic copolymers to modulate the lipid organization of cell membranes, which may provide a new strategy to design membrane-active antimicrobial agents.
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Affiliation(s)
- Kazuma Yasuhara
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 6300192, Japan. .,Center for Digital Green-Innovation, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 6300192, Japan.
| | - Manami Tsukamoto
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 6300192, Japan
| | - Jun-Ichi Kikuchi
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 6300192, Japan
| | - Kenichi Kuroda
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 N. University Ave., Ann Arbor, MI, 48109, USA
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7
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Vignoli Muniz GS, Duarte EL, Lorenzón EN, Cilli EM, Lamy MT. What different physical techniques can disclose about disruptions on membrane structure caused by the antimicrobial peptide Hylin a1 and a more positively charged analogue. Chem Phys Lipids 2022; 243:105173. [PMID: 34995561 DOI: 10.1016/j.chemphyslip.2022.105173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/15/2021] [Accepted: 01/02/2022] [Indexed: 11/28/2022]
Abstract
The present work monitors structural changes in anionic membranes (DPPG; 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol)) caused by the native antimicrobial peptide (AMP) Hylin a1 (Hya1; IFGAILPLALGALKNLIK-NH2) and its synthetic analogue K0Hya1 (KIFGAILPLALGALKNLIK-NH2), with an extra positive residue of lysine at the N-terminus of the peptide chain. Anionic membranes were used to mimic anionic lipids in bacteria membranes. Differential scanning calorimetry (DSC) evinced that both peptides strongly disrupt the lipid bilayers. However, whereas the native peptide (+3) induces a space-average and/or time-average disruption on DPPG bilayers, the more charged, K0Hya1 (+4), appears to be strongly attached to the membrane, clearly giving rise to the coexistence of two different lipid regions, one depleted of peptide and another one peptide-disrupted. The membrane fluorescent probe Laurdan indicates that, in average, the peptides increase the bilayer packing of fluid DPPG (above the lipid gel-fluid transition temperature) and/or decrease its polarity. Spin labels, incorporated into DPPG membrane, confirm, and extend the results obtained with Laurdan, indicating that the peptides increase the lipid packing both in gel and fluid DPPG bilayers. Therefore, our results confirm that Laurdan is often unable to monitor structural modifications induced on gel membranes by exogenous molecules. Through the measurement of the leakage of entrapped carboxyfluorescein (CF), a fluorescent dye, in DPPG large unilamellar vesicles it was possible to show that both peptides induce pore formation in DPPG bilayers. Furthermore, CF experiments show that Hylin peptides are strongly bound to DPPG bilayers in the gel phase, not being able to migrate to other DPPG vesicles. Here we discuss the complementarity of different techniques in monitoring structural alterations caused on lipid bilayers by Hylin peptides, and how it could be used to help in the understanding of the action of other exogenous molecules on biological membranes.
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Affiliation(s)
- Gabriel S Vignoli Muniz
- Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, 05508-090 São Paulo, SP, Brazil.
| | - Evandro L Duarte
- Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, 05508-090 São Paulo, SP, Brazil
| | - Esteban N Lorenzón
- Unidade Acadêmica Especial Ciências da Saúde, Universidade Federal de Jataí, 75804-020, Jataí, GO, Brazil
| | - Eduardo M Cilli
- Instituto de Química, Universidade Estadual Paulista, Araraquara, 14800-900, SP,,Brazil
| | - M Teresa Lamy
- Instituto de Física, Universidade de São Paulo, Rua do Matão, 1371, 05508-090 São Paulo, SP, Brazil.
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8
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Tsukamoto M, Zappala E, Caputo GA, Kikuchi JI, Najarian K, Kuroda K, Yasuhara K. Mechanistic Study of Membrane Disruption by Antimicrobial Methacrylate Random Copolymers by the Single Giant Vesicle Method. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9982-9995. [PMID: 34378943 DOI: 10.1021/acs.langmuir.1c01047] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Cationic amphiphilic polymers have been a platform to create new antimicrobial materials that act by disrupting bacterial cell membranes. While activity characterization and chemical optimization have been done in numerous studies, there remains a gap in our knowledge on the antimicrobial mechanisms of the polymers, which is needed to connect their chemical structures and biological activities. To that end, we used a single giant unilamellar vesicle (GUV) method to identify the membrane-disrupting mechanism of methacrylate random copolymers. The copolymers consist of random sequences of aminoethyl methacrylate and methyl (MMA) or butyl (BMA) methacrylate, with low molecular weights of 1600-2100 g·mol-1. GUVs consisting of an 8:2 mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), sodium salt (POPG) and those with only 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were prepared to mimic the bacterial (Escherichia coli) or mammalian membranes, respectively. The disruption of bacteria and mammalian cell membrane-mimetic lipid bilayers in GUVs reflected the antimicrobial and hemolytic activities of the copolymers, suggesting that the copolymers act by disrupting cell membranes. The copolymer with BMA formed pores in the lipid bilayer, while that with MMA caused GUVs to burst. Therefore, we propose that the mechanism is inherent to the chemical identity or properties of hydrophobic groups. The copolymer with MMA showed characteristic sigmoid curves of the time course of GUV burst. We propose a new kinetic model with a positive feedback loop in the insertion of the polymer chains in the lipid bilayer. The novel finding of alkyl-dependent membrane-disrupting mechanisms will provide a new insight into the role of hydrophobic groups in the optimization strategy for antimicrobial activity and selectivity.
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Affiliation(s)
- Manami Tsukamoto
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 6300192, Japan
| | - Emanuele Zappala
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109-2800, United States
| | - Gregory A Caputo
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | - Jun-Ichi Kikuchi
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 6300192, Japan
| | - Kayvan Najarian
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109-2800, United States
| | - Kenichi Kuroda
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Kazuma Yasuhara
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 6300192, Japan
- Center for Digital Green-innovation, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 6300192, Japan
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9
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Batista Martins D, Fadel V, Oliveira FD, Gaspar D, Alvares DS, Castanho MARB, Dos Santos Cabrera MP. Protonectin peptides target lipids, act at the interface and selectively kill metastatic breast cancer cells while preserving morphological integrity. J Colloid Interface Sci 2021; 601:517-530. [PMID: 34090029 DOI: 10.1016/j.jcis.2021.05.115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/24/2021] [Accepted: 05/20/2021] [Indexed: 12/18/2022]
Abstract
Despite the need for innovative compounds as antimicrobial and anticancer agents, natural sources of peptides remain underexplored. Protonectin (PTN), a cationic dodecapeptide of pharmacological interest, presents large hydrophobicity that is associated with the tendency to aggregate and supposedly influences bioactivity. A disaggregating role was assigned to PTN' N-terminal fragment (PTN1-6), which enhances the bioactivity of PTN in a 1:1 mixture (PTN/PTN1-6). Spectroscopic techniques and model membranes (phospholipid bilayers and SDS micelles) revealed that environment-dependent aggregation is reduced for PTN/PTN1-6, but cytotoxicity of PTNs on MDA-MB-231 breast cancer showed the same CC50 values around 16 µM and on MCF-10A epithelial breast cells 6 to 5-fold higher values, revealing a selective interaction. Since PTN1-6 lacks activity on breast cells, its presence should differently affect PTN activity, suggesting that aggregation could modulate activity depending on the membrane characteristics. Indeed, increased partitioning and lytic activity of PTN/PTN1-6 were found in model membranes independently of charge density, but affected by the curvature tendency. PTN and PTN/PTN1-6 do not alter morphology and roughness of cancer cells, indicating a superficial interaction with membranes and consistent with results obtained in NMR experiments. Our results indicate that aggregation of PTNs depends on the membrane characteristics and modulates the activity of the peptides.
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Affiliation(s)
- Danubia Batista Martins
- Departamento de Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), R. Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil
| | - Valmir Fadel
- Departamento de Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), R. Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil
| | - Filipa D Oliveira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Diana Gaspar
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Dayane S Alvares
- Departamento de Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), R. Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil
| | - Miguel A R B Castanho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Marcia Perez Dos Santos Cabrera
- Departamento de Física, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), R. Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil; Departamento de Química e Ciências Ambientais, Universidade Estadual Paulista (UNESP), Instituto de Biociências Letras e Ciências Exatas (IBILCE), R. Cristóvão Colombo, 2265, 15054-000 São José do Rio Preto, SP, Brazil.
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10
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Zhu S, Li W, O'Brien-Simpson N, Separovic F, Sani MA. C-terminus amidation influences biological activity and membrane interaction of maculatin 1.1. Amino Acids 2021; 53:769-777. [PMID: 33891157 DOI: 10.1007/s00726-021-02983-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/16/2021] [Indexed: 11/24/2022]
Abstract
Cationic antimicrobial peptides have been investigated for their potential use in combating infections by targeting the cell membrane of microbes. Their unique chemical structure has been investigated to understand their mode of action and optimize their dose-response by rationale design. One common feature among cationic AMPs is an amidated C-terminus that provides greater stability against in vivo degradation. This chemical modification also likely modulates the interaction with the cell membrane of bacteria yet few studies have been performed comparing the effect of the capping groups. We used maculatin 1.1 (Mac1) to assess the role of the capping groups in modulating the peptide bacterial efficiency, stability and interactions with lipid membranes. Circular dichroism results showed that C-terminus amidation maintains the structural stability of the peptide (α-helix) in contact with micelles. Dye leakage experiments revealed that amidation of the C-terminus resulted in higher membrane disruptive ability while bacteria and cell viability assays revealed that the amidated form displayed higher antibacterial ability and cytotoxicity compared to the acidic form of Mac1. Furthermore, 31P and 2H solid-state NMR showed that C-terminus amidation played a greater role in disturbance of the phospholipid headgroup but had little effect on the lipid tails. This study paves the way to better understand how membrane-active AMPs act in live bacteria.
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Affiliation(s)
- Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Wenyi Li
- Melbourne Dental School and Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Neil O'Brien-Simpson
- Melbourne Dental School and Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
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11
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Lee TH, Hofferek V, Sani MA, Separovic F, Reid GE, Aguilar MI. The impact of antibacterial peptides on bacterial lipid membranes depends on stage of growth. Faraday Discuss 2021; 232:399-418. [DOI: 10.1039/d0fd00052c] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Impact of maculatin 1.1 on supported lipid bilayers (SLBs) derived from early growth phase (EGP) or stationary growth phase (SGP) E. coli lipid extracts, monitored by atomic force microscopy which images bilayer morphology in real time.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Vinzenz Hofferek
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3010, 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 Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
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12
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Separovic F, Keizer DW, Sani MA. In-cell Solid-State NMR Studies of Antimicrobial Peptides. FRONTIERS IN MEDICAL TECHNOLOGY 2020; 2:610203. [PMID: 35047891 PMCID: PMC8757805 DOI: 10.3389/fmedt.2020.610203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/30/2020] [Indexed: 12/23/2022] Open
Abstract
Antimicrobial peptides (AMPs) have attracted attention as alternatives to classic antibiotics due to their expected limited pressure on bacterial resistance mechanisms. Yet, their modes of action, in particular in vivo, remain to be elucidated. In situ atomistic-scale details of complex biomolecular assemblies is a challenging requirement for deciphering the complex modes of action of AMPs. The large diversity of molecules that modulate complex interactions limits the resolution achievable using imaging methodology. Herein, the latest advances in in-cell solid-state NMR (ssNMR) are discussed, which demonstrate the power of this non-invasive technique to provide atomic details of molecular structure and dynamics. Practical requirements for investigations of intact bacteria are discussed. An overview of recent in situ NMR investigations of the architecture and metabolism of bacteria and the effect of AMPs on various bacterial structures is presented. In-cell ssNMR revealed that the studied AMPs have a disruptive action on the molecular packing of bacterial membranes and DNA. Despite the limited number of studies, in-cell ssNMR is emerging as a powerful technique to monitor in situ the interplay between bacteria and AMPs.
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Affiliation(s)
- Frances Separovic
- School of Chemistry, University of Melbourne, Melbourne, VIC, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia
| | - David W. Keizer
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Marc-Antoine Sani
- School of Chemistry, University of Melbourne, Melbourne, VIC, Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia
- *Correspondence: Marc-Antoine Sani
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13
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Benfield AH, Henriques ST. Mode-of-Action of Antimicrobial Peptides: Membrane Disruption vs. Intracellular Mechanisms. FRONTIERS IN MEDICAL TECHNOLOGY 2020; 2:610997. [PMID: 35047892 PMCID: PMC8757789 DOI: 10.3389/fmedt.2020.610997] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/20/2020] [Indexed: 12/28/2022] Open
Abstract
Antimicrobial peptides are an attractive alternative to traditional antibiotics, due to their physicochemical properties, activity toward a broad spectrum of bacteria, and mode-of-actions distinct from those used by current antibiotics. In general, antimicrobial peptides kill bacteria by either disrupting their membrane, or by entering inside bacterial cells to interact with intracellular components. Characterization of their mode-of-action is essential to improve their activity, avoid resistance in bacterial pathogens, and accelerate their use as therapeutics. Here we review experimental biophysical tools that can be employed with model membranes and bacterial cells to characterize the mode-of-action of antimicrobial peptides.
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Interaction of synthetic antimicrobial peptides of the Hylin a1 family with models of eukaryotic structures: Zwitterionic membranes and DNA. Biochem Biophys Rep 2020; 24:100827. [PMID: 33195825 PMCID: PMC7644857 DOI: 10.1016/j.bbrep.2020.100827] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/26/2020] [Accepted: 09/27/2020] [Indexed: 11/22/2022] Open
Abstract
Antimicrobial peptides (AMPs) have been appointed as a possible alternative to traditional antibiotics in face of pathogens increasing resistance to conventional drugs. Hylin a1 (IFGAILPLALGALKNLIK), an AMP extracted from the skin secretion of a South American frog, Hypsiboas albopunctatus, was found to show a strong cytotoxicity against bacteria and fungus, but also a considerable hemolytic action. Considering the toxicity of the peptide in eukaryotic cells, this work focuses on investigating the effects of the interaction of the Hylin a1 analogues W6Hya1, D0W6Hya1 and K0W6Hya1 with models of eukaryotic structures, namely zwitterionic liposomes of dipalmitoyl phosphatidylcholine (DPPC) and calf-thymus DNA (CT DNA). Through intrinsic Trp fluorescence we determined that the peptide affinity for fluid DPPC bilayers follows the decreasing order: D0W6Hya1 (+2) > W6Hya1 (+3) » K0W6Hya1 (+4). Fluorescence data also indicate that the Trp residue in the more positively charged peptide, K0W6Hya1, is less deep in the bilayer than the residue in the other two peptides. This finding is supported by differential scanning calorimetry (DSC) data, which shows that both D0W6Hya1 and W6Hya1 disturb DPPC gel-fluid transition slightly more effectively than K0W6Hya1. DPPC DSC profiles are homogeneously disturbed by the three peptides, probably related to peptide-membrane diffusion. Surprisingly, the peptide that displays the lowest affinity for PC membranes and is located at the more superficial position in the bilayer, K0W6Hya1, is the most efficient in causing formation of pores on the membrane, as attested by carboxyfluorescein leakage assays. The three peptides were found to interact with CT DNA, with a deep penetration of the Trp residue into hydrophobic pockets of the double helix, as indicated by the significant blue shift on the Trp fluorescence, and the displacement of DNA-bound ethidium bromide by the peptides. The experiments of DNA electrophoresis confirm that Hylin peptides bind DNA in a concentration-dependent manner, inducing complete DNA retardation at the relative AMP/plasmid DNA weight ratio of ~17. These findings could help to better understand the AMPs toxic effects on eukaryotic cells, thus contributing to the design of healthier therapeutic agents. AMP Hylin a1 analogues bind to both a model of eukaryotic membrane and DNA. The most cationic peptide has lowest affinity to PC vesicle and shallower binding. Peptide lower bilayer affinity is related to greater vesicle disruption and leakage. •AMP hylin a1 analogues deep penetrate into hydrophobic pockets of CT-DNA double helix.
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15
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Le Brun AP, Zhu S, Sani MA, Separovic F. The Location of the Antimicrobial Peptide Maculatin 1.1 in Model Bacterial Membranes. Front Chem 2020; 8:572. [PMID: 32733854 PMCID: PMC7358649 DOI: 10.3389/fchem.2020.00572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/03/2020] [Indexed: 12/20/2022] Open
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide (AMP) from the skin secretions of Australian tree frogs. In this work, the interaction of Mac1 with anionic phospholipid bilayers was investigated by NMR, circular dichroism (CD) spectroscopy, neutron reflectometry (NR) and molecular dynamics (MD). In buffer, the peptide is unstructured but in the presence of anionic (DPC/LMPG) micelles or (DMPC/DMPG/DHPC) bicelles adopts a helical structure. Addition of the soluble paramagnetic agent gadolinium (Gd-DTPA) into the Mac1-DPC/LMPG micelle solution showed that the N-terminus is more exposed to the hydrophilic Gd-DTPA than the C-terminus in micelles. 2H and 31P solid-state NMR showed that Mac1 had a greater effect on the anionic lipid (DMPG). A deuterium labeled Mac1 used in NR experiments indicated that the AMP spanned across anionic (PC/PG) bilayers, which was compatible with MD simulations. Simulations also showed that Mac1 orientation remained transmembrane in bilayers and wrapped on the surface of the micelles regardless of the lipid or detergent charge. Thus, the peptide orientation appears to be more susceptible to curvature than charged surface. These results support the formation of transmembrane pores by Mac1 in model bacterial membranes.
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Affiliation(s)
- Anton P Le Brun
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, NSW, Australia
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, Australia
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16
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Effect of AMPs MSI-78 and BP100 on the lipid acyl chains of 2H-labeled intact Gram positive bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183199. [DOI: 10.1016/j.bbamem.2020.183199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/05/2020] [Accepted: 01/15/2020] [Indexed: 01/30/2023]
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17
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Sani MA, Le Brun AP, Separovic F. The antimicrobial peptide maculatin self assembles in parallel to form a pore in phospholipid bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183204. [DOI: 10.1016/j.bbamem.2020.183204] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/15/2019] [Accepted: 01/21/2020] [Indexed: 01/06/2023]
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18
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Aschi M, Perini N, Bouchemal N, Luzi C, Savarin P, Migliore L, Bozzi A, Sette M. Structural characterization and biological activity of Crabrolin peptide isoforms with different positive charge. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183055. [DOI: 10.1016/j.bbamem.2019.183055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/20/2019] [Accepted: 08/25/2019] [Indexed: 12/26/2022]
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19
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Li Y, Liu T, Liu Y, Tan Z, Ju Y, Yang Y, Dong W. Antimicrobial activity, membrane interaction and stability of the D-amino acid substituted analogs of antimicrobial peptide W3R6. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 200:111645. [PMID: 31671371 DOI: 10.1016/j.jphotobiol.2019.111645] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 09/30/2019] [Accepted: 10/06/2019] [Indexed: 11/15/2022]
Abstract
Antimicrobial peptide W3R6 was derived from chensinin-1b and showed potential as a novel antibiotics. However, W3R6 was susceptible to protease cleavage, which limited its therapeutic application. To improve the proteolytic resistance of W3R6, D-amino acids were incorporated into its sequence by specific amino acid substitution or whole sequence substitution according to the specificity of the cleavage site. In this study, partially substituted analog D-Arg-W3R6 and completely substituted D-enantiomer D-W3R6 were synthesized. The resistance of D-Arg-W3R6 and D-W3R6 to cleavage by the tested protease increased, particularly of D-W3R6. The antimicrobial activity of D-Arg-W3R6 was almost the same as that of the parent peptide W3R6, but the antimicrobial activity of D-W3R6 was slightly decreased. The hemolytic activity of both D-Arg-W3R6 and D-W3R6 was negligible. The CD spectrum of D-W3R6 exhibited symmetry with that of W3R6 in a membrane-mimetic environment. The membrane interaction between the D-amino acid substituted analogs and a real/mimic bacterial cell membrane was examined. The outer membrane depolarization, inner membrane permeability and dye leakage in three types of liposomes treated with D-Arg-W3R6 and D-W3R6 were not obviously different from W3R6, which could be due to the similar physical and chemical properties. In addition, these three peptides showed the binding ability with LPS micelles detected by ITC, and their ability to disrupt the LPS micelles was examined by DLS experiment and even neutralize the surface negative charge of E. coli cells. These results suggest that D-Arg-W3R6 is a promising antibiotic molecule.
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Affiliation(s)
- Yi Li
- Department of Respiratory Medicine, Beijing Hospital, Beijing 100730, China
| | - Tong Liu
- School of Life Science, Liaoning Normal University, Dalian 116081, China
| | - Yan Liu
- Ling-Nan Medical Research Center, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Zhen Tan
- Department of Respiratory Medicine, Beijing Hospital, Beijing 100730, China
| | - Yang Ju
- Department of Respiratory Medicine, Beijing Hospital, Beijing 100730, China
| | - Yi Yang
- Ling-Nan Medical Research Center, Guangzhou University of Chinese Medicine, Guangzhou 510405, China.
| | - Weibing Dong
- School of Life Science, Liaoning Normal University, Dalian 116081, China; Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian 116081, China.
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20
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Sani MA, Zhu S, Hofferek V, Separovic F. Nitroxide spin-labeled peptides for DNP-NMR in-cell studies. FASEB J 2019; 33:11021-11027. [PMID: 31284743 DOI: 10.1096/fj.201900931r] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Antimicrobial peptides (AMPs) that target lipid membranes show promise as alternatives to conventional antibiotics. However, the molecular mechanisms of membrane perturbation, as most studies are performed in model systems and in-cell structural studies, have yet to be achieved. Solid-state NMR spectroscopy is a valuable technique to investigate peptide-membrane interactions and to determine the structure of peptides, but the short lifespan of bacteria, especially under magic angle spinning conditions, has not permitted in-cell structural studies. Here, we present the first dynamic nuclear polarization (DNP)-NMR in-cell studies of Escherichia coli bacteria incubated with the AMP maculatin 1.1 (Mac1) in combination with novel nitroxide spin-labeled peptides 2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid (TOAC)-[F3W]-Mac1 (MacW) and TOAC-TOAC-MacW. The in-cell 13C and 15N signal NMR enhancements, and 1H spin-lattice T1 relaxation times showed that TOAC-MacW and TOAC-TOAC-MacW performed better than the more hydrophilic biradical AMUPol used for DNP studies. Furthermore, the pores formed by the AMP increased the signal enhancements and decreased T1 values of specifically 13C- and 15N-labeled Mac1. This approach has a great potential for determining the first in situ structures of AMPs in bacteria.-Sani, M.-A., Zhu, S., Hofferek, V., Separovic, F. Nitroxide spin-labeled peptides for DNP-NMR in-cell studies.
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Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Vinzenz Hofferek
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
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21
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Abstract
The rise of antibiotic resistant bacteria requires unconventional strategies toward efficient chemotherapeutic agents, preferably with alternative mechanisms of action. The bacterial cell membrane has become an appealing target since its essential and highly conservative structure are key challenges to resistance mechanisms. Inspired by natural antimicrobial peptides, research on membrane-targeting antimicrobials has been growing out of the peptide space. The pursuit of more druggable molecules led to the discovery that the pharmacophore of antimicrobial peptides is smaller than anticipated. Several promising classes of membrane-targeting antimicrobials have been discovered, such as ceragenins, reutericyclines, carbohydrate amphiphiles - among others. This review will discuss the most recent findings on membrane-targeting antibiotics, focusing on small molecules outside the antimicrobial peptide molecular space.
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22
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Overall SA, Zhu S, Hanssen E, Separovic F, Sani MA. In Situ Monitoring of Bacteria under Antimicrobial Stress Using 31P Solid-State NMR. Int J Mol Sci 2019; 20:ijms20010181. [PMID: 30621328 PMCID: PMC6337522 DOI: 10.3390/ijms20010181] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/25/2018] [Accepted: 01/01/2019] [Indexed: 11/23/2022] Open
Abstract
In-cell NMR offers great insight into the characterization of the effect of toxins and antimicrobial peptides on intact cells. However, the complexity of intact live cells remains a significant challenge for the analysis of the effect these agents have on different cellular components. Here we show that 31P solid-state NMR can be used to quantitatively characterize the dynamic behaviour of DNA within intact live bacteria. Lipids were also identified and monitored, although 31P dynamic filtering methods indicated a range of dynamic states for phospholipid headgroups. We demonstrate the usefulness of this methodology for monitoring the activity of the antibiotic ampicillin and the antimicrobial peptide (AMP) maculatin 1.1 (Mac1.1) against Gram-negative bacteria. Perturbations in the dynamic behaviour of DNA were observed in treated cells, which indicated additional mechanisms of action for the AMP Mac1.1 not previously reported. This work highlights the value of 31P in-cell solid-state NMR as a tool for assessing the antimicrobial activity of antibiotics and AMPs in bacterial cells.
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Affiliation(s)
- Sarah A Overall
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
- Chemistry & Biochemistry Department, UC Santa Cruz, CA 95064, USA.
| | - Shiying Zhu
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Eric Hanssen
- Advanced Microscopy Facility and Department of Biochemistry & Molecular Biology, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Victoria 3010, Australia.
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23
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Poger D, Pöyry S, Mark AE. Could Cardiolipin Protect Membranes against the Action of Certain Antimicrobial Peptides? Aurein 1.2, a Case Study. ACS OMEGA 2018; 3:16453-16464. [PMID: 30613806 PMCID: PMC6312644 DOI: 10.1021/acsomega.8b02710] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 11/20/2018] [Indexed: 06/09/2023]
Abstract
The activity of a host of antimicrobial peptides has been examined against a range of lipid bilayers mimicking bacterial and eukaryotic membranes. Despite this, the molecular mechanisms and the nature of the physicochemical properties underlying the peptide-lipid interactions that lead to membrane disruption are yet to be fully elucidated. In this study, the interaction of the short antimicrobial peptide aurein 1.2 was examined in the presence of an anionic cardiolipin-containing lipid bilayer using molecular dynamics simulations. Aurein 1.2 is known to interact strongly with anionic lipid membranes. In the simulations, the binding of aurein 1.2 was associated with buckling of the lipid bilayer, the degree of which varied with the peptide concentration. The simulations suggest that the intrinsic properties of cardiolipin, especially the fact that it promotes negative membrane curvature, may help protect membranes against the action of peptides such as aurein 1.2 by counteracting the tendency of the peptide to induce positive curvature in target membranes.
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Affiliation(s)
- David Poger
- School
of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sanja Pöyry
- Department
of Physics, Tampere University of Technology, POB 692, F1-33720 Tampere, Finland
| | - Alan E. Mark
- School
of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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24
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Lau QY, Li J, Sani MA, Sinha S, Li Y, Ng FM, Kang C, Bhattacharjya S, Separovic F, Verma C, Chia CSB. Elucidating the bactericidal mechanism of action of the linear antimicrobial tetrapeptide BRBR-NH 2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1517-1527. [PMID: 29758185 DOI: 10.1016/j.bbamem.2018.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
Linear antimicrobial peptides, with their rapid bactericidal mode of action, are well-suited for development as topical antibacterial drugs. We recently designed a synthetic linear 4-residue peptide, BRBR-NH2, with potent bactericidal activity against Staphylococcus aureus (MIC 6.25 μM), the main causative pathogen of human skin infections with an unknown mechanism of action. Herein, we describe a series of experiments conducted to gain further insights into its mechanism of action involving electron microscopy, artificial membrane dye leakage, solution- and solid-state NMR spectroscopy followed by molecular dynamics simulations. Experimental results point towards a SMART (Soft Membranes Adapt and Respond, also Transiently) mechanism of action, suggesting that the peptide can be developed as a topical antibacterial agent for treating drug-resistant Staphylococcus aureus infections.
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Affiliation(s)
- Qiu Ying Lau
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Jianguo Li
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; Singapore Eye Research Institute, The Academia, 20 College Road, Singapore 168751, Singapore
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Sheetal Sinha
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore; Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Yan Li
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Fui Mee Ng
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - CongBao Kang
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Chandra Verma
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, Matrix #07-01, Singapore 138671, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore; Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore 117558, Singapore
| | - Cheng San Brian Chia
- Experimental Therapeutics Centre, Agency for Science, Technology and Research (A*STAR), 31 Biopolis Way, Nanos #03-01, Singapore 138669, Singapore.
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25
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Liu X, Sun B, Kell REM, Southam HM, Butler JA, Li X, Poole RK, Keene FR, Collins JG. The Antimicrobial Activity of Mononuclear Ruthenium(II) Complexes Containing the dppz Ligand. Chempluschem 2018; 83:643-650. [DOI: 10.1002/cplu.201800042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 03/27/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Xuewen Liu
- School of Physical, Environmental and Mathematical Sciences; University of New South Wales; Australian Defence Force Academy; Canberra ACT 2600 Australia
- College of Chemistry and Material Engineering; Hunan University of Arts and Science; ChangDe 415000 P. R. China
| | - Biyun Sun
- School of Physical, Environmental and Mathematical Sciences; University of New South Wales; Australian Defence Force Academy; Canberra ACT 2600 Australia
| | - Ruby E. M. Kell
- Department of Molecular Biology and Biotechnology; The University of Sheffield; Sheffield S10 2TN United Kingdom
| | - Hannah M. Southam
- Department of Molecular Biology and Biotechnology; The University of Sheffield; Sheffield S10 2TN United Kingdom
| | - Jonathan A. Butler
- Department of Molecular Biology and Biotechnology; The University of Sheffield; Sheffield S10 2TN United Kingdom
| | - Xin Li
- New Drug Screening Center; China Pharmaceutical University; Nanjing JiangSu Province 210009 P. R. China
| | - Robert K. Poole
- Department of Molecular Biology and Biotechnology; The University of Sheffield; Sheffield S10 2TN United Kingdom
| | - F. Richard Keene
- School of Physical Sciences; University of Adelaide; Adelaide SA 5005 Australia
- Australian Institute of Tropical Health & Medicine; Centre for Biodiscovery & Molecular Development of Therapeutics; James Cook University; Townsville QLD 4811 Australia
| | - J. Grant Collins
- School of Physical, Environmental and Mathematical Sciences; University of New South Wales; Australian Defence Force Academy; Canberra ACT 2600 Australia
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26
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Zhu S, Sani M, Separovic F. Interaction of cationic antimicrobial peptides from Australian frogs with lipid membranes. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Shiying Zhu
- School of ChemistryBio21 Institute, University of MelbourneMelbourne VIC3010 Australia
| | - Marc‐Antoine Sani
- School of ChemistryBio21 Institute, University of MelbourneMelbourne VIC3010 Australia
| | - Frances Separovic
- School of ChemistryBio21 Institute, University of MelbourneMelbourne VIC3010 Australia
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27
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Lee TH, Sani MA, Overall S, Separovic F, Aguilar MI. Effect of phosphatidylcholine bilayer thickness and molecular order on the binding of the antimicrobial peptide maculatin 1.1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:300-309. [DOI: 10.1016/j.bbamem.2017.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 09/18/2017] [Accepted: 10/08/2017] [Indexed: 01/01/2023]
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28
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Sani MA, Separovic F. Antimicrobial Peptide Structures: From Model Membranes to Live Cells. Chemistry 2017; 24:286-291. [PMID: 29068097 DOI: 10.1002/chem.201704362] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Indexed: 01/12/2023]
Abstract
The rise in antibiotic resistance has led to a renewed interest in antimicrobial peptides (AMPs) that target membranes. The mode of action of AMPs involves the disruption of the lipid bilayer and leads to growth inhibition and death of the bacteria. However, details at the molecular level of how these peptides kill bacteria and the reasons for the observed differences in selectivity remain unclear. Structural information is crucial for defining the molecular mechanism by which these peptides recognize, self-assemble and interact with a particular lipid membrane. Solid-state NMR is a non-invasive technique that allows the study of the structural details of lipid-peptide and peptide-peptide interactions. Following on from studies of antibiotic and lytic peptides, gramicidin A and melittin, respectively, we investigated maculatin 1.1, an AMP from the skin of Australian tree frogs that acts against Gram-positive bacteria. By using perdeuterated phospholipids and specifically labelled peptides, 2 H, 31 P and {31 P}15 N REDOR solid-state NMR experiments have been used to localize, maculatin 1.1 in neutral and anionic model membranes. However, the structure, location and activity depend on the composition of the model membrane and current advances in solid-state NMR spectroscopy now allow structure determination of AMPs in live bacteria.
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Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
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29
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Phenylalanine residues act as membrane anchors in the antimicrobial action of Aurein 1.2. Biointerphases 2017; 12:05G605. [PMID: 29078702 DOI: 10.1116/1.4995674] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aurein 1.2 is a small cationic antimicrobial peptide, one of the shortest peptides that can exert antimicrobial activity at low micromolar concentrations. Aurein 1.2 is a surface acting peptide, following the "carpet" mechanism of thresholded membrane disruption. It is generally assumed that the activity of such cationic α-helical membrane disrupting peptides is charge driven. Here, the authors show that instead of charge interactions, aromatic phenylalanine residues of the Aurein 1.2 sequence facilitate the membrane binding. The activity of the wild type peptide was compared to mutants in which the Phe residues were substituted, singly and in tandem, with alanine. Measurements by quartz crystal microbalance, impedance spectroscopy, and dye leakage experiments demonstrated that single residue mutants retain a much-reduced activity whereas the deletion of both Phe residues prevents membrane disruption entirely. The single residue mutants exhibited an altered mechanism of action, permeabilizing but not dissolving the target membranes. These results offer a new design rule for membrane disrupting peptides with potential pharmacological applications.
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30
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Han ML, Shen HH, Hansford KA, Schneider EK, Sivanesan S, Roberts KD, Thompson PE, Le Brun AP, Zhu Y, Sani MA, Separovic F, Blaskovich MAT, Baker MA, Moskowitz SM, Cooper MA, Li J, Velkov T. Investigating the Interaction of Octapeptin A3 with Model Bacterial Membranes. ACS Infect Dis 2017; 3:606-619. [PMID: 28695731 DOI: 10.1021/acsinfecdis.7b00065] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Octapeptins are cyclic lipopeptides with a broader spectrum of activity against fungi and polymyxin-resistant Gram-negative and Gram-positive bacteria. In the present study, we investigated the interaction of octapeptin A3 with asymmetric outer membrane models of Gram-negative pathogen Pseudomonas aeruginosa using neutron reflectometry, together with fluorimetric and calorimetry methods. For the first time, our neutron reflectometry results reveal that the interaction of octapeptin A3 with the Gram-negative outer membrane involves an initial transient polar interaction with the phospholipid and lipid A headgroups, followed by the penetration of the entire octapeptin molecule into the fatty acyl core of the outer membrane. This mechanism contrasts with that of polymyxin B, which specifically targets lipid A, whereas octapeptins appear to target both lipid A and phospholipids. Furthermore, the mechanism of octapeptins does not appear to be highly dependent on an initial complementary electrostatic interaction with lipid A, which accounts for their ability to bind to lipid A of polymyxin-resistant Gram-negative bacteria that is modified with cationic moieties that act to electrostatically repel the cationic polymyxin molecule. The presented findings shed new light on the mechanism whereby octapeptins penetrate the outer membrane of polymyxin-resistant Gram-negative pathogens and highlight their potential as candidates for development as new antibiotics against problematic multi-drug-resistant pathogens.
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Affiliation(s)
- Mei-Ling Han
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | | | - Karl A. Hansford
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elena K. Schneider
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Sivashangarie Sivanesan
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Kade D. Roberts
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Philip E. Thompson
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Anton P. Le Brun
- Bragg Institute, Australian
Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Yan Zhu
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Mark A. T. Blaskovich
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mark A. Baker
- Priority Research Centre in Reproductive
Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Samuel M. Moskowitz
- Vertex Pharmaceuticals, 50 Northern Avenue, Boston, Massachusetts 02210, United States
| | - Matthew A. Cooper
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Tony Velkov
- Drug
Development and Innovation, Drug Delivery, Disposition and Dynamics,
Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria Australia
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31
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Sani MA, Carne S, Overall SA, Poulhazan A, Separovic F. One pathogen two stones: are Australian tree frog antimicrobial peptides synergistic against human pathogens? EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:639-646. [PMID: 28478484 DOI: 10.1007/s00249-017-1215-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/28/2017] [Accepted: 04/24/2017] [Indexed: 01/10/2023]
Abstract
Antimicrobial peptides (AMPs) may act by targeting the lipid membranes and disrupting the bilayer structure. In this study, three AMPs from the skin of Australian tree frogs, aurein 1.2, maculatin 1.1 and caerin 1.1, were investigated against Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus, and vesicles that mimic their lipid compositions. Furthermore, equimolar mixtures of the peptides were tested to identify any synergistic interactions in antimicrobial activity. Minimum inhibition concentration and minimum bactericidal concentration assays showed significant activity against S. aureus but not against E. coli. Aurein was the least active while maculatin was the most active peptide and some synergistic effects were observed against S. aureus. Circular dichroism experiments showed that, in the presence of phospholipid vesicles, the peptides transitioned from an unstructured to a predominantly helical conformation (>50%), with greater helicity for POPG/TOCL compared to POPE/POPG vesicles. The helical content, however, was less in the presence of live E. coli and S. aureus, 25 and 5%, respectively. Equimolar concentrations of the peptides did not appear to form greater supramolecular structures. Dye release assays showed that aurein required greater concentration than caerin and maculatin to disrupt the lipid bilayers, and mixtures of the peptides did not cooperate to enhance their lytic activity. Overall, aurein, maculatin, and caerin showed moderate synergy in antimicrobial activity against S. aureus without becoming more structured or enhancement of their membrane-disrupting activity in phospholipid vesicles.
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Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
| | - Siobhan Carne
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Sarah A Overall
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Alexandre Poulhazan
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia
- Universite Pierre et Marie Curie (Paris VI), 4 Place Jussieu, 75252, Paris Cedex 5, France
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, VIC, 3010, Australia.
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Hanatoxin inserts into phospholipid membranes without pore formation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:917-923. [PMID: 28143758 DOI: 10.1016/j.bbamem.2017.01.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 01/21/2017] [Accepted: 01/26/2017] [Indexed: 11/23/2022]
Abstract
Hanatoxin (HaTx), a 35-residue polypeptide from spider venom, functions as an inhibitor of Kv2.1 channels by interacting with phospholipids prior to affecting the voltage-sensor. However, how this water-soluble peptide modifies the gating remains poorly understood, as the voltage-sensor is deeply embedded within the bilayer. To determine how HaTx interacts with phospholipid bilayers, in this study, we examined the toxin-induced partitioning of liposomal membranes. HPLC-results from high-speed spin-down vesicles with HaTx demonstrated direct binding. Dynamic light scattering (DLS) and leakage assay results further indicated that neither membrane pores nor membrane fragmentations were observed in the presence of HaTx. To clarify the binding details, Langmuir trough experiments were performed with phospholipid monolayers by mimicking the external leaflet of membrane bilayers, indicating the involvement of acyl chains in such interactions between HaTx and phospholipids. Our current study thus describes the interaction pattern of HaTx with vesicle membranes, defining a membrane-partitioning mechanism for peptide insertion involving the membrane hydrocarbon core without pore formation.
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33
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Peptide-based strategies for enhanced cell uptake, transcellular transport, and circulation: Mechanisms and challenges. Adv Drug Deliv Rev 2017; 110-111:52-64. [PMID: 27313077 DOI: 10.1016/j.addr.2016.06.002] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/27/2016] [Accepted: 06/06/2016] [Indexed: 12/12/2022]
Abstract
Peptides are emerging as a new tool in drug and gene delivery. Peptide-drug conjugates and peptide-modified drug delivery systems provide new opportunities to avoid macrophage recognition and subsequent phagocytosis, cross endothelial and epithelial barriers, and enter the cytoplasm of target cells. Peptides are relatively small, low-cost, and are stable in a wide range of biological conditions. In this review, we summarize recent work in designing peptides to enhance penetration of biological barriers, increase cell uptake, and avoid the immune system. We highlight recent successes and contradictory results, and outline common emerging concepts and design rules. The development of sequence-structure-function relationships and standard protocols for benchmarking will be a key to progress in the field.
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34
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O'Brien-Simpson NM, Li W, Pantarat N, Hossain MA, Separovic F, Wade JD, Reynolds EC. Fluorescent Ion Efflux Screening Assay for Determining Membrane-Active Peptides. Aust J Chem 2017. [DOI: 10.1071/ch16659] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A major global health threat is the emergence of antibiotic-resistant microbes. Coupled with a lack of development of modified antibiotics, there is a need to develop new antimicrobial molecules and screening assays for them. In this study, we provide proof of concept that a large unilamellar vesicle (LUV) method used to study chloride ion efflux facilitated by ionophores and surfactant-like molecules that disrupt membrane integrity can be adapted to identify membrane-interactive antimicrobial peptides (AMPs) and to screen relative activity of AMPs. Lucigenin was encapsulated in LUVs in the presence of Cl– ion (NaCl), which quenches fluorescence, and then incubated with AMPs in 100 mM NaNO3 buffer. Upon AMP membrane interaction or disruption, the Cl– ion is exchanged with the NO3– ion, and the resultant lucigenin fluorescence is indicative of relative AMP activity. Seven AMPs were synthesized by solid-phase peptide chemistry and incubated with LUVs of different phospholipid compositions. Each AMP resulted in lucigenin fluorescence, which was dose dependent, and the relative fluorescence correlated with the minimum inhibitory concentration and minimum bactericidal concentration values for the corresponding peptide. Furthermore, using mammalian model phospholipid LUVs, lucigenin-induced fluorescence also correlated with the AMP cytotoxicity half-maximal inhibitory concentration values. The proline-rich AMP, Chex1-Arg20, which is non-lytic but interacts with the bacterial membrane resulted in lucigenin fluorescence of bacterial membrane model LUVs but not of mammalian membrane model LUVs. The fluorescent ion efflux assay developed here should have applicability for most AMPs and could be tailored to target particular bacterial species membrane composition, potentially leading to the identification of novel membrane-interactive AMPs. The rapid high-throughput method also allows for screening of relative AMP activity and toxicity before biological testing.
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35
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Fillion M, Goudreault M, Voyer N, Bechinger B, Auger M. Amphiphilicity Is a Key Determinant in the Membrane Interactions of Synthetic 14-mer Cationic Peptide Analogues. Biochemistry 2016; 55:6919-6930. [DOI: 10.1021/acs.biochem.6b00961] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
| | | | | | - Burkhard Bechinger
- Université de Strasbourg, CNRS, UMR7177, Institut de
Chimie, 4, Rue Blaise
Pascal, 67070 Strasbourg, France
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36
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Abstract
The structure-function relationship for a family of antimicrobial peptides (AMPs) from the skin of Australian tree frogs is discussed and compared with that of peptide toxins from bee and Australian scorpion venoms. Although these membrane-active peptides induce a similar cellular fate by disrupting the lipid bilayer integrity, their lytic activity is achieved via different modes of action, which are investigated in relation to amino acid sequence, secondary structure, and membrane lipid composition. In order to better understand what structural features govern the interaction between peptides and lipid membranes, cell-penetrating peptides (CPPs), which translocate through the membrane without compromising its integrity, are also discussed. AMPs possess membrane lytic activities that are naturally designed to target the cellular membrane of pathogens or competitors. They are extremely diverse in amino acid composition and often show specificity against a particular strain of microbe. Since our antibiotic arsenal is declining precariously in the face of the rise in multiantibiotic resistance, AMPs increasingly are seen as a promising alternative. In an effort to understand their molecular mechanism, biophysical studies of a myriad of AMPs have been reported, yet no unifying mechanism has emerged, rendering difficult the rational design of drug leads. Similarly, a wide variety of cytotoxic peptides are found in venoms, the best known being melittin, yet again, predicting their activity based on a particular amino acid composition or secondary structure remains elusive. A common feature of these membrane-active peptides is their preference for the lipid environment. Indeed, they are mainly unstructured in solution and, in the presence of lipid membranes, quickly adsorb onto the surface, change their secondary structure, eventually insert into the hydrophobic core of the membrane bilayer, and finally disrupt the bilayer integrity. These steps define the molecular mechanism by which these membrane-active peptides lyse membranes. The last class of membrane-active peptides discussed are the CPPs, which translocate across the lipid bilayer without inducing severe disruption and have potential as drug vehicles. CPPs are typically highly charged and can show antimicrobial activity by targeting an intracellular target rather than via a direct membrane lytic mechanism. A critical aspect in the structure-function relationship of membrane-active peptides is their specific activity relative to the lipid membrane composition of the cell target. Cell membranes have a wide diversity of lipids, and those of eukaryotic and prokaryotic species differ greatly in composition and structure. The activity of AMPs from Australian tree frogs, toxins, and CPPs has been investigated within various lipid systems to assess whether a relationship between peptide and membrane composition could be identified. NMR spectroscopy techniques are being used to gain atomistic details of how these membrane-active peptides interact with model membranes and cells, and in particular, competitive assays demonstrate the difference between affinity and activity for a specific lipid environment. Overall, the interactions between these relatively small sized peptides and various lipid bilayers give insight into how these peptides function at the membrane interface.
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Affiliation(s)
- Marc-Antoine Sani
- School of Chemistry, Bio21
Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21
Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
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37
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Hayden RM, Goldberg GK, Ferguson BM, Schoeneck MW, Libardo MDJ, Mayeux SE, Shrestha A, Bogardus KA, Hammer J, Pryshchep S, Lehman HK, McCormick ML, Blazyk J, Angeles-Boza AM, Fu R, Cotten ML. Complementary Effects of Host Defense Peptides Piscidin 1 and Piscidin 3 on DNA and Lipid Membranes: Biophysical Insights into Contrasting Biological Activities. J Phys Chem B 2015; 119:15235-46. [DOI: 10.1021/acs.jpcb.5b09685] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robert M. Hayden
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Gina K. Goldberg
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Bryan M. Ferguson
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Mason W. Schoeneck
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - M. Daben J. Libardo
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Sophie E. Mayeux
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Akritee Shrestha
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Kimberly A. Bogardus
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
| | - Janet Hammer
- Department
of Biomedical Sciences, Ohio University, Athens, Ohio 45701, United States
| | - Sergey Pryshchep
- Center
for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Herman K. Lehman
- Department
of Biology, Hamilton College, Clinton, New York 13323, United States
| | | | - Jack Blazyk
- Department
of Biomedical Sciences, Ohio University, Athens, Ohio 45701, United States
| | - Alfredo M. Angeles-Boza
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Riqiang Fu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
| | - Myriam L. Cotten
- Department
of Chemistry, Hamilton College, Clinton, New York 13323, United States
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38
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Shahmiri M, Enciso M, Mechler A. Controls and constrains of the membrane disrupting action of Aurein 1.2. Sci Rep 2015; 5:16378. [PMID: 26574052 PMCID: PMC4648102 DOI: 10.1038/srep16378] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/13/2015] [Indexed: 11/21/2022] Open
Abstract
Aurein 1.2 is a 13 residue antimicrobial peptide secreted by the Australian tree frog Litoria Aurea. It is a surface-acting membrane disrupting peptide that permeabilizes bacterial membranes via the carpet mechanism; the molecular details of this process are mostly unknown. Here the mechanism of action of Aurein 1.2 was investigated with an emphasis on the role of membrane charge and C-terminal amidation of the peptide. Using quartz crystal microbalance (QCM) fingerprinting it was found that the membrane charge correlates with membrane affinity of the peptide, however the binding and the membrane disrupting processes are not charge driven; increased membrane charge reduces the membrane disrupting activity. Coarse grain simulations revealed that phenylalanine residues act as membrane anchors. Accordingly Aurein 1.2 has the ability to bind to any membrane. Furthermore, bundling precludes membrane disruption in case of wild type peptides, while non C-terminal amidated peptides form random aggregates leading to detachment from the membrane. Hence C-terminal amidation is crucial for Aurein 1.2 action. Our results suggest that Aurein 1.2 acts via aggregation driven membrane penetration. The concomitant change in the tension of the outer leaflet imposes a spontaneous curvature on the membrane, leading to disintegration.
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Affiliation(s)
- Mahdi Shahmiri
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora Vic 3086, Australia
| | - Marta Enciso
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora Vic 3086, Australia
| | - Adam Mechler
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora Vic 3086, Australia
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39
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Sani MA, Henriques ST, Weber D, Separovic F. Bacteria May Cope Differently from Similar Membrane Damage Caused by the Australian Tree Frog Antimicrobial Peptide Maculatin 1.1. J Biol Chem 2015; 290:19853-62. [PMID: 26100634 DOI: 10.1074/jbc.m115.643262] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Indexed: 11/06/2022] Open
Abstract
Maculatin 1.1 (Mac1) is an antimicrobial peptide from the skin of Australian tree frogs and is known to possess selectivity toward Gram-positive bacteria. Although Mac1 has membrane disrupting activity, it is not known how Mac1 selectively targets Gram-positive over Gram-negative bacteria. The interaction of Mac1 with Escherichia coli, Staphylococcus aureus, and human red blood cells (hRBC) and with their mimetic model membranes is here reported. The peptide showed a 16-fold greater growth inhibition activity against S. aureus (4 μM) than against E. coli (64 μM) and an intermediate cytotoxicity against hRBC (30 μM). Surprisingly, Sytox Green uptake monitored by flow cytometry showed that Mac1 compromised both bacterial membranes with similar efficiency at ∼20-fold lower concentration than the reported minimum inhibition concentration against S. aureus. Mac1 also reduced the negative potential of S. aureus and E. coli membrane with similar efficacy. Furthermore, liposomes mimicking the cell membrane of S. aureus (POPG/TOCL) and E. coli (POPE/POPG) were lysed at similar concentrations, whereas hRBC-like vesicles (POPC/SM/Chol) remained mostly intact in the presence of Mac1. Remarkably, when POPG/TOCL and POPE/POPG liposomes were co-incubated, Mac1 did not induce leakage from POPE/POPG liposomes, suggesting a preference toward POPG/TOCL membranes that was supported by surface plasma resonance assays. Interestingly, circular dichroism spectroscopy showed a similar helical conformation in the presence of the anionic liposomes but not the hRBC mimics. Overall, the study showed that Mac1 disrupts bacterial membranes in a similar fashion before cell death events and would preferentially target S. aureus over E. coli or hRBC membranes.
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Affiliation(s)
- Marc-Antoine Sani
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Sónia Troeira Henriques
- the Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Daniel Weber
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Frances Separovic
- From the School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia and
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40
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Sani MA, Separovic F. Progression of NMR studies of membrane-active peptides from lipid bilayers to live cells. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 253:138-142. [PMID: 25631783 DOI: 10.1016/j.jmr.2014.11.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 11/24/2014] [Accepted: 11/30/2014] [Indexed: 06/04/2023]
Abstract
Understanding the structure of membrane-active peptides faces many challenges associated with the development of appropriate model membrane systems as the peptide structure depends strongly on the lipid environment. This perspective provides a brief overview of the approach taken to study antimicrobial and amyloid peptides in phospholipid bilayers using oriented bilayers and magic angle spinning techniques. In particular, Boltzmann statistics REDOR and maximum entropy analysis of spinning side bands are used to analyse systems where multiple states of peptide or lipid molecules may co-exist. We propose that in future, rather than model membranes, structural studies in whole cells are feasible.
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Affiliation(s)
- M-A Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, VIC 3010, Australia
| | - F Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, VIC 3010, Australia.
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41
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Lee DK, Bhunia A, Kotler SA, Ramamoorthy A. Detergent-type membrane fragmentation by MSI-78, MSI-367, MSI-594, and MSI-843 antimicrobial peptides and inhibition by cholesterol: a solid-state nuclear magnetic resonance study. Biochemistry 2015; 54:1897-907. [PMID: 25715195 DOI: 10.1021/bi501418m] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Multidrug resistance against the existing antibiotics is becoming a global threat, and any potential drug that can be designed using cationic antimicrobial peptides (AMP) could be an alternate solution to alleviate this existing problem. The mechanism of action of killing bacteria by an AMP differs drastically in comparison to that of small molecule antibiotics. The main target of AMPs is to interact with the lipid bilayer of the cell membrane and disrupt it to kill bacteria. Consequently, the modes of membrane interaction that lead to the selectivity of an AMP are very important to understand. Here, we have used different membrane compositions, such as negatively charged, zwitterionic, or mixed large unilamellar vesicles (LUVs), to study the interaction of four different synthetically designed cationic, linear antimicrobial peptides: MSI-78 (commercially known as pexiganan), MSI-367, MSI-594, and MSI-843. Our solid-state nuclear magnetic resonance (NMR) experiments confirmed that the MSI peptides fragmented LUVs through a detergent-like carpet mechanism depending on the amino acid sequence of the MSI peptide and/or the membrane composition of LUVs. Interestingly, the fragmented lipid aggregates such as SUVs or micelles are sufficiently small to produce an isotropic peak in the (31)P NMR spectrum. These fragmented lipid aggregates contain only MSI peptides bestowed with lipid molecules as confirmed by NMR in conjunction with circular dichroism spectroscopy. Our results also demonstrate that cholesterol, which is present only in the eukaryotic cell membrane, inhibits the MSI-induced fragmentation of LUVs, suggesting that the MSI peptides can discriminate the bacteria and the eukaryotic cell membranes, and this selectivity could be used for further development of novel antibiotics.
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Affiliation(s)
- Dong-Kuk Lee
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Anirban Bhunia
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States.,§Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII(M), Kolkata 700054, India
| | - Samuel A Kotler
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Ayyalusamy Ramamoorthy
- †Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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42
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Alkhammash HI, Li N, Berthier R, de Planque MRR. Native silica nanoparticles are powerful membrane disruptors. Phys Chem Chem Phys 2015; 17:15547-60. [DOI: 10.1039/c4cp05882h] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Silica nanoparticles permeabilize liposomal membranes as a function of nanoparticle size, surface chemistry and biocoating as well as membrane charge.
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Affiliation(s)
- Hend I. Alkhammash
- Electronics and Computer Science & Institute for Life Sciences
- University of Southampton
- Southampton
- UK
- Department of Physics
| | - Nan Li
- Electronics and Computer Science & Institute for Life Sciences
- University of Southampton
- Southampton
- UK
| | - Rémy Berthier
- Electronics and Computer Science & Institute for Life Sciences
- University of Southampton
- Southampton
- UK
| | - Maurits R. R. de Planque
- Electronics and Computer Science & Institute for Life Sciences
- University of Southampton
- Southampton
- UK
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