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Rooney J, Rivera-de-Torre E, Li R, Mclean K, Price DR, Nisbet AJ, Laustsen AH, Jenkins TP, Hofmann A, Bakshi S, Zarkan A, Cantacessi C. Structural and functional analyses of nematode-derived antimicrobial peptides support the occurrence of direct mechanisms of worm-microbiota interactions. Comput Struct Biotechnol J 2024; 23:1522-1533. [PMID: 38633385 PMCID: PMC11021794 DOI: 10.1016/j.csbj.2024.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/07/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
The complex relationships between gastrointestinal (GI) nematodes and the host gut microbiota have been implicated in key aspects of helminth disease and infection outcomes. Nevertheless, the direct and indirect mechanisms governing these interactions are, thus far, largely unknown. In this proof-of-concept study, we demonstrate that the excretory-secretory products (ESPs) and extracellular vesicles (EVs) of key GI nematodes contain peptides that, when recombinantly expressed, exert antimicrobial activity in vitro against Bacillus subtilis. In particular, using time-lapse microfluidics microscopy, we demonstrate that exposure of B. subtilis to a recombinant saposin-domain containing peptide from the 'brown stomach worm', Teladorsagia circumcincta, and a metridin-like ShK toxin from the 'barber's pole worm', Haemonchus contortus, results in cell lysis and significantly reduced growth rates. Data from this study support the hypothesis that GI nematodes may modulate the composition of the vertebrate gut microbiota directly via the secretion of antimicrobial peptides, and pave the way for future investigations aimed at deciphering the impact of such changes on the pathophysiology of GI helminth infection and disease.
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Affiliation(s)
- James Rooney
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Ruizhe Li
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Kevin Mclean
- Moredun Research Institute, Penicuik Midlothian, United Kingdom
| | | | | | - Andreas H. Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Timothy P. Jenkins
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Andreas Hofmann
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kulmbach, Germany
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Somenath Bakshi
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Ashraf Zarkan
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Cinzia Cantacessi
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
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2
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Brendel M, Kohler TP, Neufend JV, Puppe A, Gisch N, Hammerschmidt S. Lipoteichoic Acids Are Essential for Pneumococcal Colonization and Membrane Integrity. J Innate Immun 2024; 16:370-384. [PMID: 38901409 PMCID: PMC11324232 DOI: 10.1159/000539934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 06/18/2024] [Indexed: 06/22/2024] Open
Abstract
INTRODUCTION The hydrophilic, polymeric chain of the lipoteichoic acid (LTA) of the Gram-positive pathobiont Streptococcus pneumoniae is covalently linked to the glycosylglycerolipid α-d-glucopyranosyl-(1,3)-diacylglycerol by the LTA ligase TacL, leading to its fixation in the cytoplasmic membrane. Pneumococcal LTA, sharing identical repeating units with the wall teichoic acids (WTA), is dispensable for normal growth but required for full virulence in invasive infections. METHODS Mutants deficient in TacL and complemented strains constructed were tested for their growth, resistance against oxidative stress, and susceptibility against antimicrobial peptides. Further, the membrane fluidity of pneumococci, their capability to adhere to lung epithelial cells, and virulence in a Galleria mellonella as well as intranasal mouse infection model were assessed. RESULTS In the present study, we indicate that LTA is already indispensable for pneumococcal adherence to human nasopharyngeal cells and colonization in an intranasal mouse infection model. Mutants deficient for TacL did not show morphological defects. However, our analysis of pneumococcal membranes in different serotypes showed an altered membrane fluidity and surface protein abundance of lipoproteins in mutants deficient for LTA but not WTA. These mutants had a decreased membrane fluidity, exhibited higher amounts of lipoproteins, and showed an increased susceptibility to antimicrobial peptides. In complemented mutant strains, this defect was fully restored. CONCLUSION Taken together, LTA is crucial for colonization and required to effectively protect pneumococci from innate immune defence mechanisms by maintaining the membrane integrity.
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Affiliation(s)
- Max Brendel
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Thomas P. Kohler
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Janine V. Neufend
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Astrid Puppe
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
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3
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Wei C, Pohorille A. Multi-oligomeric states of alamethicin ion channel: Assemblies and conductance. Biophys J 2023; 122:2531-2543. [PMID: 37161094 PMCID: PMC10323028 DOI: 10.1016/j.bpj.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 04/03/2023] [Accepted: 05/04/2023] [Indexed: 05/11/2023] Open
Abstract
Transmembrane assemblies of the peptaibol alamethicin (ALM) are among the most extensively studied ion channels not only because of their antimicrobial activity but also as models for channel structure and aggregation. In this study, several oligomeric states of ALM are investigated with molecular dynamics simulations to establish properties of the channel and obtain free energy profiles for ion transport and the corresponding values of conductance. The hexamer, heptamer, and octamer of ALM in phospholipid membrane are found to be stable but highly dynamic in barrel-stave structures, with calculated conductance equal to 18, 195, and 1270 pS, respectively, in 1 M KCl ion solution. The corresponding free energy profiles, reported for the first time, are reconstructed from simulations at applied voltage of 200 mV with the aid of the electrodiffusion model both with and without the knowledge of diffusivity. The calculated free energy barriers are equal to 2.5, 1.5, and 0.5 kcal/mol for K+ and 4.0, 2.2, and 1.5 kcal/mol for Cl-, for hexamer, heptamer, and octamer, respectively. The calculated conductance and the ratio between conductance in consecutive states are in good agreement with those measured experimentally. This suggests that the hexamer is the lowest conducting state, with measured conductance equal to 19 pS. The selectivity of K+ over Cl- is calculated as 1.5 and 2.3 for the octameric and heptameric channels, close to the selectivity measured for high-conductance states. Selectivity increases to 13 in the hexameric channel in which the narrowest Gln7 site has a pore radius of only ∼1.6 Å, again in accord with experiment. A good agreement found between calculated and measured conductance through a hexamer templated on cyclodextrin lands additional support for the results of our simulations, and the comparison with ALM reveals the dependence of conductance on the nature of phospholipid membrane.
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Affiliation(s)
- Chenyu Wei
- NASA Ames Research Center, Moffett Field, California; SETI Institute, Mountain View, California.
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4
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Singh V, Macharová S, Riegerová P, Steringer JP, Müller HM, Lolicato F, Nickel W, Hof M, Šachl R. Determining the Functional Oligomeric State of Membrane-Associated Protein Oligomers Forming Membrane Pores on Giant Lipid Vesicles. Anal Chem 2023. [PMID: 37148264 DOI: 10.1021/acs.analchem.2c05692] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Several peripheral membrane proteins are known to form membrane pores through multimerization. In many cases, in biochemical reconstitution experiments, a complex distribution of oligomeric states has been observed that may, in part, be irrelevant to their physiological functions. This phenomenon makes it difficult to identify the functional oligomeric states of membrane lipid interacting proteins, for example, during the formation of transient membrane pores. Using fibroblast growth factor 2 (FGF2) as an example, we present a methodology applicable to giant lipid vesicles by which functional oligomers can be distinguished from nonspecifically aggregated proteins without functionality. Two distinct populations of fibroblast growth factor 2 were identified with (i) dimers to hexamers and (ii) a broad population of higher oligomeric states of membrane-associated FGF2 oligomers significantly distorting the original unfiltered histogram of all detectable oligomeric species of FGF2. The presented statistical approach is relevant for various techniques for characterizing membrane-dependent protein oligomerization.
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Affiliation(s)
- Vandana Singh
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu, 2027/3, 121 16 Prague, Czech Republic
| | - Sabína Macharová
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Petra Riegerová
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Julia P Steringer
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Hans-Michael Müller
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Fabio Lolicato
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, 182 23 Prague, Czech Republic
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Maleš M, Zoranić L. Simulation Study of the Effect of Antimicrobial Peptide Associations on the Mechanism of Action with Bacterial and Eukaryotic Membranes. MEMBRANES 2022; 12:891. [PMID: 36135911 PMCID: PMC9502835 DOI: 10.3390/membranes12090891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/06/2022] [Accepted: 09/09/2022] [Indexed: 06/16/2023]
Abstract
Antimicrobial peptides (AMPs) can be directed to specific membranes based on differences in lipid composition. In this study, we performed atomistic and coarse-grained simulations of different numbers of the designed AMP adepantin-1 with a eukaryotic membrane, cytoplasmic Gram-positive and Gram-negative membranes, and an outer Gram-negative membrane. At the core of adepantin-1's behavior is its amphipathic α-helical structure, which was implemented in its design. The amphipathic structure promotes rapid self-association of peptide in water or upon binding to bacterial membranes. Aggregates initially make contact with the membrane via positively charged residues, but with insertion, the hydrophobic residues are exposed to the membrane's hydrophobic core. This adaptation alters the aggregate's stability, causing the peptides to diffuse in the polar region of the membrane, mostly remaining as a single peptide or pairing up to form an antiparallel dimer. Thus, the aggregate's proposed role is to aid in positioning the peptide into a favorable conformation for insertion. Simulations revealed the molecular basics of adepantin-1 binding to various membranes, and highlighted peptide aggregation as an important factor. These findings contribute to the development of novel anti-infective agents to combat the rapidly growing problem of bacterial resistance to antibiotics.
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Affiliation(s)
- Matko Maleš
- Faculty of Maritime Studies, University of Split, 21000 Split, Croatia
| | - Larisa Zoranić
- Department of Physics, Faculty of Science, University of Split, 21000 Split, Croatia
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6
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Syryamina VN, Afanasyeva EF, Dzuba SA, Formaggio F, De Zotti M. Peptide-membrane binding is not enough to explain bioactivity: A case study. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183978. [PMID: 35659865 DOI: 10.1016/j.bbamem.2022.183978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/11/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Membrane-active peptides are a promising class of antimicrobial and anticancer therapeutics. For this reason, their molecular mechanisms of action are currently actively investigated. By exploiting Electron Paramagnetic Resonance, we study the membrane interaction of two spin-labeled analogs of the antimicrobial and cytotoxic peptide trichogin GA IV (Tri), with opposite bioactivity: Tri(Api8), able to selectively kill cancer cells, and Tri(Leu4), which is completely nontoxic. In our attempt to determine the molecular basis of their different biological activity, we investigate peptide impact on the lateral organization of lipid membranes, peptide localization and oligomerization, in the zwitter-ionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) model membrane We show that, despite their divergent bioactivity, both peptide analogs (i) are membrane-bound, (ii) display a weak tendency to oligomerization, and (iii) do not induce significant lipid rearrangement. Conversely, literature data show that the parent peptide trichogin, which is cytotoxic without any selectivity, is strongly prone to dimerization and affects the reorganization of POPC membranes. Its dimers are involved in the rotation around the peptide helix, as observed at cryogenic temperatures in the millisecond timescale. Since this latter behavior is not observed for the inactive Tri(Leu4), we propose that for short-length peptides as trichogin oligomerization and molecular motions are crucial for bioactivity, and membrane binding alone is not enough to predict or explain it. We envisage that small changes in the peptide sequence that affect only their ability to oligomerize, or their molecular motions inside the membrane, can tune the peptide activity on membranes of different compositions.
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Affiliation(s)
- Victoria N Syryamina
- Voevodsky Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation.
| | - Ekaterina F Afanasyeva
- Voevodsky Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation
| | - Sergei A Dzuba
- Voevodsky Institute of Chemical Kinetics and Combustion, RAS, Novosibirsk 630090, Russian Federation; Department of Physics, Novosibirsk State University,630090 Novosibirsk, Russian Federation
| | - Fernando Formaggio
- ICB-CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy
| | - Marta De Zotti
- ICB-CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy.
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7
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Rodríguez-Galván A, Contreras-Torres FF. Scanning Tunneling Microscopy of Biological Structures: An Elusive Goal for Many Years. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3013. [PMID: 36080050 PMCID: PMC9457988 DOI: 10.3390/nano12173013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/29/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Scanning tunneling microscopy (STM) is a technique that can be used to directly observe individual biomolecules at near-molecular scale. Within this framework, STM is of crucial significance because of its role in the structural analysis, the understanding the imaging formation, and the development of relative techniques. Four decades after its invention, it is pertinent to ask how much of the early dream has come true. In this study, we aim to overview different analyses for DNA, lipids, proteins, and carbohydrates. The relevance of STM imaging is exhibited as an opportunity to assist measurements and biomolecular identification in nanobiotechnology, nanomedicine, biosensing, and other cutting-edge applications. We believe STM research is still an entire science research ecosystem for joining several areas of expertise towards a goal settlement that has been elusive for many years.
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Affiliation(s)
- Andrés Rodríguez-Galván
- Carrera de Biología, Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Edo. Mex., Mexico
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8
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Su Z, Leitch JJ, Lipkowski J. Effect of Lipid Composition on the Inhibition Mechanism of Amiloride on Alamethicin Ion Channels in Supported Phospholipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:8398-8406. [PMID: 35749587 DOI: 10.1021/acs.langmuir.2c00953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The inhibition effect of amiloride on alamethicin ion channels was studied in a model zwitterionic floating bilayer lipid membrane (fBLM). The EIS studies indicated that amiloride prevents the transport of ions through the alamethicin channels leading to an overall increase in membrane resistance. The PM-IRRAS data demonstrated that amiloride has no influence on the secondary structure of alamethicin but restricts the insertion of the peptides into the bilayer and blocks ion transport through preformed alamethicin channels. The effect of amiloride on ion channel formation in the floating bilayer formed by a zwitterionic lipid was compared to those of previous studies involving negatively charged fBLMs and tethered zwitterionic lipid bilayers. The findings from these studies show that the effects of amiloride on ion channel formation strongly depend on the mobility and charge of the membrane lipids.
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Affiliation(s)
- ZhangFei Su
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - J Jay Leitch
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Al Nahas K, Fletcher M, Hammond K, Nehls C, Cama J, Ryadnov MG, Keyser UF. Measuring Thousands of Single-Vesicle Leakage Events Reveals the Mode of Action of Antimicrobial Peptides. Anal Chem 2022; 94:9530-9539. [PMID: 35760038 PMCID: PMC9280716 DOI: 10.1021/acs.analchem.1c03564] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
![]()
Host defense or antimicrobial
peptides hold promise for providing
new pipelines of effective antimicrobial agents. Their activity quantified
against model phospholipid membranes is fundamental to a detailed
understanding of their structure–activity relationships. However,
classical characterization assays often lack the ability to achieve
this insight. Leveraging a highly parallelized microfluidic platform
for trapping and studying thousands of giant unilamellar vesicles,
we conducted quantitative long-term microscopy studies to monitor
the membrane-disruptive activity of archetypal antimicrobial peptides
with a high spatiotemporal resolution. We described the modes of action
of these peptides via measurements of the disruption of the vesicle
population under the conditions of continuous peptide dosing using
a range of concentrations and related the observed modes to the molecular
activity mechanisms of these peptides. The study offers an effective
approach for characterizing membrane-targeting antimicrobial agents
in a standardized manner and for assigning specific modes of action
to the corresponding antimicrobial mechanisms.
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Affiliation(s)
- Kareem Al Nahas
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Marcus Fletcher
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K.,London Centre for Nanotechnology, University College London, London WC1H 0AH, U.K
| | - Christian Nehls
- Research Center Borstel, Leibniz Lung Center, Parkallee 10, Borstel 23845, Germany
| | - Jehangir Cama
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K.,Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, U.K.,College of Engineering, Mathematics and Physical Sciences, University of Exeter, North Park Road, Exeter EX4 4QF, U.K
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K.,Department of Physics, King's College London, Strand Lane, London WC2R 2LS, U.K
| | - Ulrich F Keyser
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K
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10
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Wu Y, Gooding JJ. The application of single molecule nanopore sensing for quantitative analysis. Chem Soc Rev 2022; 51:3862-3885. [PMID: 35506519 DOI: 10.1039/d1cs00988e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Nanopore-based sensors typically work by monitoring transient pulses in conductance via current-time traces as molecules translocate through the nanopore. The unique property of being able to monitor single molecules gives nanopore sensors the potential as quantitative sensors based on the counting of single molecules. This review provides an overview of the concepts and fabrication of nanopore sensors as well as nanopore sensing with a view toward using nanopore sensors for quantitative analysis. We first introduce the classification of nanopores and highlight their applications in molecular identification with some pioneering studies. The review then shifts focus to recent strategies to extend nanopore sensors to devices that can rapidly and accurately quantify the amount of an analyte of interest. Finally, future prospects are provided and briefly discussed. The aim of this review is to aid in understanding recent advances, challenges, and prospects for nanopore sensors for quantitative analysis.
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Affiliation(s)
- Yanfang Wu
- School of Chemistry and Australian Centre for NanoMedicine, The University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - J Justin Gooding
- School of Chemistry and Australian Centre for NanoMedicine, The University of New South Wales, Sydney, New South Wales 2052, Australia.
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Szabó I, Yousef M, Soltész D, Bató C, Mező G, Bánóczi Z. Redesigning of Cell-Penetrating Peptides to Improve Their Efficacy as a Drug Delivery System. Pharmaceutics 2022; 14:pharmaceutics14050907. [PMID: 35631493 PMCID: PMC9146218 DOI: 10.3390/pharmaceutics14050907] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/11/2022] [Accepted: 04/13/2022] [Indexed: 12/29/2022] Open
Abstract
Cell-penetrating peptides (CPP) are promising tools for the transport of a broad range of compounds into cells. Since the discovery of the first members of this peptide family, many other peptides have been identified; nowadays, dozens of these peptides are known. These peptides sometimes have very different chemical–physical properties, but they have similar drawbacks; e.g., non-specific internalization, fast elimination from the body, intracellular/vesicular entrapment. Although our knowledge regarding the mechanism and structure–activity relationship of internalization is growing, the prediction and design of the cell-penetrating properties are challenging. In this review, we focus on the different modifications of well-known CPPs to avoid their drawbacks, as well as how these modifications may increase their internalization and/or change the mechanism of penetration.
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Affiliation(s)
- Ildikó Szabó
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös Loránd Research Network (ELKH), Eötvös Loránd University, 1117 Budapest, Hungary;
- Correspondence: (I.S.); (Z.B.)
| | - Mo’ath Yousef
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Dóra Soltész
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Csaba Bató
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Gábor Mező
- MTA-ELTE Research Group of Peptide Chemistry, Eötvös Loránd Research Network (ELKH), Eötvös Loránd University, 1117 Budapest, Hungary;
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
| | - Zoltán Bánóczi
- Department of Organic Chemistry, Institute of Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (M.Y.); (D.S.); (C.B.)
- Correspondence: (I.S.); (Z.B.)
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12
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Rotational Dynamics of The Transmembrane Domains Play an Important Role in Peptide Dynamics of Viral Fusion and Ion Channel Forming Proteins—A Molecular Dynamics Simulation Study. Viruses 2022; 14:v14040699. [PMID: 35458429 PMCID: PMC9024552 DOI: 10.3390/v14040699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/02/2022] [Accepted: 03/20/2022] [Indexed: 02/04/2023] Open
Abstract
Focusing on the transmembrane domains (TMDs) of viral fusion and channel-forming proteins (VCPs), experimentally available and newly generated peptides in an ideal conformation of the S and E proteins of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and SARS-CoV, gp41 and Vpu, both of human immunodeficiency virus type 1 (HIV-1), haemagglutinin and M2 of influenza A, as well as gB of herpes simplex virus (HSV), are embedded in a fully hydrated lipid bilayer and used in multi-nanosecond molecular dynamics simulations. It is aimed to identify differences in the dynamics of the individual TMDs of the two types of viral membrane proteins. The assumption is made that the dynamics of the individual TMDs are decoupled from their extra-membrane domains, and that the mechanics of the TMDs are distinct from each other due to the different mechanism of function of the two types of proteins. The diffusivity coefficient (DC) of the translational and rotational diffusion is decreased in the oligomeric state of the TMDs compared to those values when calculated from simulations in their monomeric state. When comparing the calculations for two different lengths of the TMD, a longer full peptide and a shorter purely TMD stretch, (i) the difference of the calculated DCs begins to level out when the difference exceeds approximately 15 amino acids per peptide chain, and (ii) the channel protein rotational DC is the most affected diffusion parameter. The rotational dynamics of the individual amino acids within the middle section of the TMDs of the fusion peptides remain high upon oligomerization, but decrease for the channel peptides, with an increasing number of monomers forming the oligomeric state, suggesting an entropic penalty on oligomerization for the latter.
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13
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Xiao D, Zhang M, Wu P, Li T, Li W, Zhang L, Yue Q, Chen X, Wei X, Xu Y, Wang C. Halovirs I–K, antibacterial and cytotoxic lipopeptaibols from the plant pathogenic fungus Paramyrothecium roridum NRRL 2183. J Antibiot (Tokyo) 2022; 75:247-257. [DOI: 10.1038/s41429-022-00517-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 02/15/2022] [Accepted: 02/20/2022] [Indexed: 11/09/2022]
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14
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Li S, Wu L, Zhu M, Cheng X, Jiang X. Effect of dipole potential on the orientation of Voltage-gated Alamethicin peptides regulated by chaotropic anions. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2021.115880] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Guidelli R, Becucci L. Functional activity of peptide ion channels in tethered bilayer lipid membranes: Review. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Rolando Guidelli
- Department of Chemistry University of Florence Sesto Fiorentino Firenze Italy
| | - Lucia Becucci
- Ministero dell'Istruzione Scuola Media “Guglielmo Marconi” San Giovanni Valdarno Arezzo Italy
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16
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Kratochvil HT, Newberry RW, Mensa B, Mravic M, DeGrado WF. Spiers Memorial Lecture: Analysis and de novo design of membrane-interactive peptides. Faraday Discuss 2021; 232:9-48. [PMID: 34693965 PMCID: PMC8979563 DOI: 10.1039/d1fd00061f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Membrane-peptide interactions play critical roles in many cellular and organismic functions, including protection from infection, remodeling of membranes, signaling, and ion transport. Peptides interact with membranes in a variety of ways: some associate with membrane surfaces in either intrinsically disordered conformations or well-defined secondary structures. Peptides with sufficient hydrophobicity can also insert vertically as transmembrane monomers, and many associate further into membrane-spanning helical bundles. Indeed, some peptides progress through each of these stages in the process of forming oligomeric bundles. In each case, the structure of the peptide and the membrane represent a delicate balance between peptide-membrane and peptide-peptide interactions. We will review this literature from the perspective of several biologically important systems, including antimicrobial peptides and their mimics, α-synuclein, receptor tyrosine kinases, and ion channels. We also discuss the use of de novo design to construct models to test our understanding of the underlying principles and to provide useful leads for pharmaceutical intervention of diseases.
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Affiliation(s)
- Huong T Kratochvil
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Robert W Newberry
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Bruk Mensa
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Marco Mravic
- Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
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17
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Czernek J, Brus J. Modeling the Structure of Crystalline Alamethicin and Its NMR Chemical Shift Tensors. Antibiotics (Basel) 2021; 10:1265. [PMID: 34680845 PMCID: PMC8532780 DOI: 10.3390/antibiotics10101265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 11/25/2022] Open
Abstract
Alamethicin (ALM) is an antimicrobial peptide that is frequently employed in studies of the mechanism of action of pore-forming molecules. Advanced techniques of solid-state NMR spectroscopy (SSNMR) are important in these studies, as they are capable of describing the alignment of helical peptides, such as ALM, in lipid bilayers. Here, it is demonstrated how an analysis of the SSNMR measurements can benefit from fully periodic calculations, which employ the plane-wave density-functional theory (PW DFT) of the solid-phase geometry and related spectral parameters of ALM. The PW DFT calculations are used to obtain the structure of desolvated crystalline ALM and predict the NMR chemical shift tensors (CSTs) of its nuclei. A variation in the CSTs of the amidic nitrogens and carbonyl carbons along the ALM backbone is evaluated and included in simulations of the orientation-dependent anisotropic 15N and 13C chemical shift components. In this way, the influence of the site-specific structural effects on the experimentally determined orientation of ALM is shown in models of cell membranes.
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Affiliation(s)
- Jiří Czernek
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, 16206 Prague, Czech Republic;
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18
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Kang S, Lumactud R, Li N, Bell TH, Kim HS, Park SY, Lee YH. Harnessing Chemical Ecology for Environment-Friendly Crop Protection. PHYTOPATHOLOGY 2021; 111:1697-1710. [PMID: 33908803 DOI: 10.1094/phyto-01-21-0035-rvw] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Heavy reliance on synthetic pesticides for crop protection has become increasingly unsustainable, calling for robust alternative strategies that do not degrade the environment and vital ecosystem services. There are numerous reports of successful disease control by various microbes used in small-scale trials. However, inconsistent efficacy has hampered their large-scale application. A better understanding of how beneficial microbes interact with plants, other microbes, and the environment and which factors affect disease control efficacy is crucial to deploy microbial agents as effective and reliable pesticide alternatives. Diverse metabolites produced by plants and microbes participate in pathogenesis and defense, regulate the growth and development of themselves and neighboring organisms, help maintain cellular homeostasis under various environmental conditions, and affect the assembly and activity of plant and soil microbiomes. However, research on the metabolites associated with plant health-related processes, except antibiotics, has not received adequate attention. This review highlights several classes of metabolites known or suspected to affect plant health, focusing on those associated with biocontrol and belowground plant-microbe and microbe-microbe interactions. The review also describes how new insights from systematic explorations of the diversity and mechanism of action of bioactive metabolites can be harnessed to develop novel crop protection strategies.
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Affiliation(s)
- Seogchan Kang
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Rhea Lumactud
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Ningxiao Li
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Terrence H Bell
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Hye-Seon Kim
- USDA, Agricultural Research Service, National Center for Agricultural Utilization Research, Mycotoxin Prevention and Applied Microbiology Research Unit, Peoria, IL 61604, U.S.A
| | - Sook-Young Park
- Department of Agricultural Life Science, Sunchon National University, Suncheon 57922, Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
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19
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Antibiofilm activity of host defence peptides: complexity provides opportunities. Nat Rev Microbiol 2021; 19:786-797. [PMID: 34183822 DOI: 10.1038/s41579-021-00585-w] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2021] [Indexed: 12/21/2022]
Abstract
Host defence peptides (HDPs) are integral components of innate immunity across all living organisms. These peptides can exert direct antibacterial effects, targeting planktonic cells (referred to as antimicrobial peptides), and exhibit antibiofilm (referred to as antibiofilm peptides), antiviral, antifungal and host-directed immunomodulatory activities. In this Review, we discuss how the complex functional attributes of HDPs provide many opportunities for the development of antimicrobial therapeutics, focusing particularly on their emerging antibiofilm properties. The mechanisms of action of antibiofilm peptides are compared and contrasted with those of antimicrobial peptides. Furthermore, obstacles for the practical translation of candidate peptides into therapeutics and the potential solutions are discussed. Critically, HDPs have the value-added assets of complex functional attributes, particularly antibiofilm and anti-inflammatory activities and their synergy with conventional antibiotics.
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20
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Sancho-Vaello E, Gil-Carton D, François P, Bonetti EJ, Kreir M, Pothula KR, Kleinekathöfer U, Zeth K. The structure of the antimicrobial human cathelicidin LL-37 shows oligomerization and channel formation in the presence of membrane mimics. Sci Rep 2020; 10:17356. [PMID: 33060695 PMCID: PMC7562864 DOI: 10.1038/s41598-020-74401-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 09/26/2020] [Indexed: 12/22/2022] Open
Abstract
The human cathelicidin LL-37 serves a critical role in the innate immune system defending bacterial infections. LL-37 can interact with molecules of the cell wall and perforate cytoplasmic membranes resulting in bacterial cell death. To test the interactions of LL-37 and bacterial cell wall components we crystallized LL-37 in the presence of detergents and obtained the structure of a narrow tetrameric channel with a strongly charged core. The formation of a tetramer was further studied by cross-linking in the presence of detergents and lipids. Using planar lipid membranes a small but defined conductivity of this channel could be demonstrated. Molecular dynamic simulations underline the stability of this channel in membranes and demonstrate pathways for the passage of water molecules. Time lapse studies of E. coli cells treated with LL-37 show membrane discontinuities in the outer membrane followed by cell wall damage and cell death. Collectively, our results open a venue to the understanding of a novel AMP killing mechanism and allows the rational design of LL-37 derivatives with enhanced bactericidal activity.
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Affiliation(s)
- Enea Sancho-Vaello
- Unidad de Biofisica, Centro Mixto Consejo Superior de Investigaciones Cientificas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC, UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia, Spain.,Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - David Gil-Carton
- Structural Biology Unit, CIC bioGUNE, Parque Tecnológico de Bizkaia Edificio 800, 48160, Derio, Spain
| | - Patrice François
- Genomic Research Laboratory, Department of Medical Specialities, Geneva University Hospitals, University of Geneva, Genève, Switzerland
| | - Eve-Julie Bonetti
- Genomic Research Laboratory, Department of Medical Specialities, Geneva University Hospitals, University of Geneva, Genève, Switzerland
| | - Mohamed Kreir
- Nanion Technologies GmbH, Gabrielenstraße 9, 80636, Munich, Germany.,Janssen Pharmaceutica NV, Janssen R&D, Nonclinical Safety, Beerse, Belgium
| | - Karunakar Reddy Pothula
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Kornelius Zeth
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000, Roskilde, Denmark.
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21
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León Madrazo A, Segura Campos MR. Review of antimicrobial peptides as promoters of food safety: Limitations and possibilities within the food industry. J Food Saf 2020. [DOI: 10.1111/jfs.12854] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Anaí León Madrazo
- Facultad de Ingeniería Química Universidad Autónoma de Yucatán Mérida Yucatán Mexico
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22
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Shoji K, Kawano R, White RJ. Analysis of Membrane Protein Deinsertion-Associated Currents with Nanoneedle-Supported Bilayers to Discover Pore Formation Mechanisms. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10012-10021. [PMID: 32787048 DOI: 10.1021/acs.langmuir.0c00833] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Analysis of the pore formation mechanisms of biological nanopores can provide insight into pore-forming peptide-induced diseases and into the characterization of nanopores employed in sensing methods. Evaluation of pore formation mechanisms is typically performed using microscopy including atomic force microscopy, transmission electron microscopy, as well as electrically via channel current measurements using a patch-clamp amplifier. However, due to the relatively low temporal resolution of the above-mentioned microscopy techniques and the low analysis accuracy of the channel current measurements, new analytical methods are required. Here, we describe a new analytical strategy to measure and analyze both ionic currents associated with biological nanopore insertion and deinsertion into and out of lipid bilayers to determine pore formation mechanisms for several representative proteins. The current changes associated with protein deinsertion are monitored as the lipid membrane leaflets are pulled apart-a unique phenomenon enabled by our gold nanoneedle measurement probe. This deinsertion current analysis (DiCA) is performed using a gold nanoneedle-supported lipid bilayer at which a bilayer membrane is formed by bringing together two lipid monolayers on the surface of the nanoneedle and at the interface of an aqueous solution and a lipid/oil mixture. The lipid bilayer can be pulled apart by removing the nanoneedle from this interface. In this study, we demonstrate the determination of pore formation mechanisms for four different pore-forming proteins and peptides-α-hemolysin, streptolysin O, alamethicin, and amyloid β 1-42 using DiCA. As a result, we successfully discern the pore formation mechanism, either addition or expansion, for each protein/peptide by analyzing the ratio and magnitude of insertion and deinsertion current events.
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Affiliation(s)
- Kan Shoji
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
- Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka, Niigata 840-2188, Japan
| | - Ryuji Kawano
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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23
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Mrdenovic D, Su Z, Kutner W, Lipkowski J, Pieta P. Alzheimer's disease-related amyloid β peptide causes structural disordering of lipids and changes the electric properties of a floating bilayer lipid membrane. NANOSCALE ADVANCES 2020; 2:3467-3480. [PMID: 36134289 PMCID: PMC9417616 DOI: 10.1039/d0na00292e] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/27/2020] [Indexed: 05/10/2023]
Abstract
Neurodegeneration in Alzheimer's disease is associated with disruption of the neuronal cell membrane by the amyloid β (Aβ) peptide. However, the disruption mechanism and the resulting changes in membrane properties remain to be elucidated. To address this issue, herein the interaction of amyloid β monomers (AβMs) and amyloid β oligomers (AβOs) with a floating bilayer lipid membrane (fBLM) was studied using electrochemical and IR spectroscopy techniques. IR measurements showed that both Aβ forms interacted similarly with the hydrophobic membrane core (lipid acyl chains), causing conformational and orientational changes of the lipid acyl chains, thus decreasing acyl chain mobility and altering the lipid packing unit cell. In the presence of AβOs, these changes were more significant than those in the presence of AβMs. However, respective interactions of AβMs and AβOs with the membrane hydrophilic exterior (lipid heads) were quite different. AβMs dehydrated lipid heads without affecting their orientation while AβOs changed the orientation of lipid heads keeping their hydration level intact. Electrochemical measurements showed that only AβOs porated the fBLM, thus significantly changing the fBLM electrical properties. The present results provide new molecular-level insight into the mechanism of membrane destruction by AβOs and changes in the membrane properties.
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Affiliation(s)
- Dusan Mrdenovic
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Department of Chemistry, University of Guelph 50 Stone Road East Guelph Ontario N1G 2W1 Canada
| | - Zhangfei Su
- Department of Chemistry, University of Guelph 50 Stone Road East Guelph Ontario N1G 2W1 Canada
| | - Wlodzimierz Kutner
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Faculty of Mathematics and Natural Sciences, School of Sciences, Cardinal Stefan Wyszynski University in Warsaw Wóycickiego 1/3 01-815 Warsaw Poland
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph 50 Stone Road East Guelph Ontario N1G 2W1 Canada
| | - Piotr Pieta
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
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24
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Bera PK, Kandar AK, Krishnaswamy R, Fontaine P, Impéror-Clerc M, Pansu B, Constantin D, Maiti S, Sanyal MK, Sood AK. Grazing Incidence X-ray Diffraction Studies of Lipid-Peptide Mixed Monolayers during Shear Flow. ACS OMEGA 2020; 5:14555-14563. [PMID: 32596593 PMCID: PMC7315600 DOI: 10.1021/acsomega.0c01261] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 04/10/2020] [Indexed: 05/20/2023]
Abstract
Grazing incidence X-ray diffraction (GIXD) studies of monolayers of biomolecules at an air-water interface give quantitative information of in-plane packing, coherence length of crystalline domains, etc. Rheo-GIXD measurements can reveal quantitative changes in the nanocrystalline domains of a monolayer under shear. Here, we report GIXD studies of monolayers of alamethicin peptide, DPPC lipid, and their mixtures at an air-water interface under steady shear stress. The alamethicin monolayer and the mixed monolayer show a flow jamming transition. On the other hand, the pure 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayer under constant stress flows steadily with a notable enhancement of the area/molecule and coherence lengths, suggesting the fusion of nanocrystallites during flow. The DPPC-alamethicin mixed monolayer shows no significant change in the area/DPPC molecule, but the coherence lengths of the individual phases (DPPC and alamethicin) increase, suggesting that the crystallites of individual phases grow bigger by merging of domains. More phase separation occurs in the system during flow. Our results show that rheo-GIXD has the potential to explore in situ molecular structural changes under rheological conditions for a diverse range of confined biomolecules at interfaces.
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Affiliation(s)
- Pradip K. Bera
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Ajoy K. Kandar
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
- Soft Condensed Matter,
Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Rema Krishnaswamy
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
- School of Liberal
Studies, Azim Premji University, Bangalore 560100, India
| | - Philippe Fontaine
- SOLEIL Synchrotron, L’Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette
Cedex, France
| | - Marianne Impéror-Clerc
- Laboratoire de Physique des
Solides, Unité Mixte de Recherche 8502 Centre National de la
Recherche Scientifique, Université
Paris-Sud 11, 91405 Orsay Cedex, France
| | - Brigitte Pansu
- Laboratoire de Physique des
Solides, Unité Mixte de Recherche 8502 Centre National de la
Recherche Scientifique, Université
Paris-Sud 11, 91405 Orsay Cedex, France
| | - Doru Constantin
- Laboratoire de Physique des
Solides, Unité Mixte de Recherche 8502 Centre National de la
Recherche Scientifique, Université
Paris-Sud 11, 91405 Orsay Cedex, France
| | - Santanu Maiti
- Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
| | - Milan K. Sanyal
- Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India
| | - A. K. Sood
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
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25
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Peters AD, Borsley S, Della Sala F, Cairns-Gibson DF, Leonidou M, Clayden J, Whitehead GFS, Vitórica-Yrezábal IJ, Takano E, Burthem J, Cockroft SL, Webb SJ. Switchable foldamer ion channels with antibacterial activity. Chem Sci 2020; 11:7023-7030. [PMID: 32953034 PMCID: PMC7481839 DOI: 10.1039/d0sc02393k] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 06/04/2020] [Indexed: 12/19/2022] Open
Abstract
Synthetic ion channels may have applications in treating channelopathies and as new classes of antibiotics, particularly if ion flow through the channels can be controlled. Here we describe triazole-capped octameric α-aminoisobutyric acid (Aib) foldamers that "switch on" ion channel activity in phospholipid bilayers upon copper(ii) chloride addition; activity is "switched off" upon copper(ii) extraction. X-ray crystallography showed that CuCl2 complexation gave chloro-bridged foldamer dimers, with hydrogen bonds between dimers producing channels within the crystal structure. These interactions suggest a pathway for foldamer self-assembly into membrane ion channels. The copper(ii)-foldamer complexes showed antibacterial activity against B. megaterium strain DSM319 that was similar to the peptaibol antibiotic alamethicin, but with 90% lower hemolytic activity.
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Affiliation(s)
- Anna D Peters
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
| | - Stefan Borsley
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK
| | - Flavio Della Sala
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
| | - Dominic F Cairns-Gibson
- EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK
| | - Marios Leonidou
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
| | - Jonathan Clayden
- School of Chemistry , University of Bristol , Cantock's Close , Bristol BS8 1TS , UK
| | - George F S Whitehead
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | | | - Eriko Takano
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
| | - John Burthem
- Department of Haematology , Manchester Royal Infirmary , Manchester University NHS Foundation Trust , Manchester M13 9WL , UK.,Division of Cancer Sciences , School of Medical Sciences , University of Manchester , Manchester , UK
| | - Scott L Cockroft
- EaStCHEM School of Chemistry , University of Edinburgh , Joseph Black Building, David Brewster Road , Edinburgh EH9 3FJ , UK
| | - Simon J Webb
- Department of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK . .,Manchester Institute of Biotechnology , University of Manchester , 131 Princess St , Manchester M1 7DN , UK
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26
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27
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Malanovic N, Marx L, Blondelle SE, Pabst G, Semeraro EF. Experimental concepts for linking the biological activities of antimicrobial peptides to their molecular modes of action. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183275. [PMID: 32173291 DOI: 10.1016/j.bbamem.2020.183275] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023]
Abstract
The search for novel compounds to combat multi-resistant bacterial infections includes exploring the potency of antimicrobial peptides and derivatives thereof. Complementary to high-throughput screening techniques, biophysical and biochemical studies of the biological activity of these compounds enable deep insight, which can be exploited in designing antimicrobial peptides with improved efficacy. This approach requires the combination of several techniques to study the effect of such peptides on both bacterial cells and simple mimics of their cell envelope, such as lipid-only vesicles. These efforts carry the challenge of bridging results across techniques and sample systems, including the proper choice of membrane mimics. This review describes some important concepts toward the development of potent antimicrobial peptides and how they translate to frequently applied experimental techniques, along with an outline of the biophysics pertaining to the killing mechanism of antimicrobial peptides.
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Affiliation(s)
- Nermina Malanovic
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria.
| | - Lisa Marx
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
| | | | - Georg Pabst
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
| | - Enrico F Semeraro
- University of Graz, Institute of Molecular Biosciences, Biophysics Division, Graz, Austria
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28
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Su Z, Juhaniewicz-Debinska J, Sek S, Lipkowski J. Water Structure in the Submembrane Region of a Floating Lipid Bilayer: The Effect of an Ion Channel Formation and the Channel Blocker. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:409-418. [PMID: 31815479 DOI: 10.1021/acs.langmuir.9b03271] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The structure of water in the submembrane region of the bilayer of DPhPC floating (fBLM) on a monolayer of 1-thio-β-d-glucose (β-Tg)-modified gold nanoparticle film was studied by the surface-enhanced infrared absorption spectroscopy (SEIRAS). SEIRAS employs surface enhancement of the mean square electric field of the photon, which is acting on a few molecular layers above the film of gold nanoparticles. Therefore, it is uniquely suited to probe water molecules in the submembrane region and provides unique information concerning the structure of the hydrogen bond network of water surrounding the lipid bilayer. The IR spectra indicated that water with a strong hydrogen network is separating the membrane from the gold surface. This water is more ordered than the water in the bulk. When alamethicin, a peptide forming ion channels, is inserted into the membrane, the network is only slightly loosened. The addition of amiloride, an ion channel blocker, results in a significant decrease in the amount of water in the submembrane region. The remaining water has a significantly distorted hydrogen bond network. This study provides unique information about the effect of the ion channel on water transport across the bilayer. The electrode potential has a relatively small effect on water structure in the submembrane region. However, the IR studies demonstrated that water is less ordered at positive transmembrane potentials. The present results provide significant insight into the nature of hydration of a floating lipid bilayer on the gold electrode surface.
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Affiliation(s)
- ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Joanna Juhaniewicz-Debinska
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Slawomir Sek
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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29
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Carloni LE, Bezzu CG, Bonifazi D. Patterning Porous Networks through Self-Assembly of Programmed Biomacromolecules. Chemistry 2019; 25:16179-16200. [PMID: 31491049 DOI: 10.1002/chem.201902576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/11/2019] [Indexed: 11/08/2022]
Abstract
Two-dimensional (2D) porous networks are of great interest for the fabrication of complex organized functional materials for potential applications in nanotechnologies and nanoelectronics. This review aims at providing an overview of bottom-up approaches towards the engineering of 2D porous networks by using biomacromolecules, with a particular focus on nucleic acids and proteins. The first part illustrates how the advancements in DNA nanotechnology allowed for the attainment of complex ordered porous two-dimensional DNA nanostructures, thanks to a biomimetic approach based on DNA molecules self-assembly through specific hydrogen-bond base pairing. The second part focuses the attention on how polypeptides and proteins structural properties could be used to engineer organized networks templating the formation of multifunctional materials. The structural organization of all examples is discussed as revealed by scanning probe microscopy or transmission electron microscopy imaging techniques.
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Affiliation(s)
- Laure-Elie Carloni
- Department of Chemistry and Namur Research College (NARC), University of Namur, Rue de Bruxelles 61, Namur, 5000, Belgium
| | - C Grazia Bezzu
- Cardiff University, School of Chemistry, Park Place, Main Building, CF10 3AT, Cardiff, Wales, UK
| | - Davide Bonifazi
- Cardiff University, School of Chemistry, Park Place, Main Building, CF10 3AT, Cardiff, Wales, UK
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Beyond electrostatics: Antimicrobial peptide selectivity and the influence of cholesterol-mediated fluidity and lipid chain length on protegrin-1 activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:182977. [DOI: 10.1016/j.bbamem.2019.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/11/2019] [Accepted: 04/28/2019] [Indexed: 12/31/2022]
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Mechanisms of alamethicin ion channel inhibition by amiloride in zwitterionic tethered lipid bilayers. J Electroanal Chem (Lausanne) 2019. [DOI: 10.1016/j.jelechem.2019.113281] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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32
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Accelerated Molecular Dynamics Applied to the Peptaibol Folding Problem. Int J Mol Sci 2019; 20:ijms20174268. [PMID: 31480404 PMCID: PMC6747184 DOI: 10.3390/ijms20174268] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/24/2019] [Accepted: 08/27/2019] [Indexed: 01/18/2023] Open
Abstract
The use of enhanced sampling molecular dynamics simulations to facilitate the folding of proteins is a relatively new approach which has quickly gained momentum in recent years. Accelerated molecular dynamics (aMD) can elucidate the dynamic path from the unfolded state to the near-native state, “flattened” by introducing a non-negative boost to the potential. Alamethicin F30/3 (Alm F30/3), chosen in this study, belongs to the class of peptaibols that are 7–20 residue long, non-ribosomally synthesized, amphipathic molecules that show interesting membrane perturbing activity. The recent studies undertaken on the Alm molecules and their transmembrane channels have been reviewed. Three consecutive simulations of ~900 ns each were carried out where N-terminal folding could be observed within the first 100 ns, while C-terminal folding could only be achieved almost after 800 ns. It took ~1 μs to attain the near-native conformation with stronger potential boost which may take several μs worth of classical MD to produce the same results. The Alm F30/3 hexamer channel was also simulated in an E. coli mimicking membrane under an external electric field that correlates with previous experiments. It can be concluded that aMD simulation techniques are suited to elucidate peptaibol structures and to understand their folding dynamics.
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Abbasi F, Su Z, Alvarez-Malmagro J, Leitch JJ, Lipkowski J. Effects of Amiloride, an Ion Channel Blocker, on Alamethicin Pore Formation in Negatively Charged, Gold-Supported, Phospholipid Bilayers: A Molecular View. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5060-5068. [PMID: 30888178 DOI: 10.1021/acs.langmuir.9b00187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The effects of amiloride on the structure and conductivity of alamethicin ion pore formation within negatively charged, gold-supported, 1,2-dimyristoyl- sn-glycero-3-phosphocholine/Egg-PG membranes were investigated with the help of electrochemical impedance spectroscopy (EIS), photon polarization modulation-infrared reflection spectroscopy (PM-IRRAS), and atomic force microscopy (AFM). The EIS results indicate that ion conductivity across negatively charged phospholipid bilayers containing alamethicin decreases by an order of magnitude when amiloride is introduced to the system. Despite the reduction in ion conductivity, the PM-IRRAS data shows that amiloride does not inhibit ion channel formation by alamethicin peptides. High-resolution AFM images revealed that amiloride enlarges and distorts the shape of alamethicin ion pores when introduced to the system, indicating that it is inserting itself into the mouth of the alamethicin pores. This effect is driven by electrostatic interactions between positively charged amiloride molecules and the negative charge on the membrane.
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Affiliation(s)
- Fatemeh Abbasi
- Department of Chemistry , University of Guelph , Guelph , Ontario , Canada N1G 2W1
| | - ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario , Canada N1G 2W1
| | | | - J Jay Leitch
- Department of Chemistry , University of Guelph , Guelph , Ontario , Canada N1G 2W1
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario , Canada N1G 2W1
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Jeong KB, Luo K, Lee H, Lim MC, Yu J, Choi SJ, Kim KB, Jeon TJ, Kim YR. Alpha-Hederin Nanopore for Single Nucleotide Discrimination. ACS NANO 2019; 13:1719-1727. [PMID: 30657663 DOI: 10.1021/acsnano.8b07797] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Various types of biological and synthetic nanopores have been developed and utilized for the high-throughput investigation of individual biomolecules. Biological nanopores made with channel proteins are so far superior to solid-state ones in terms of sensitivity and reproducibility. However, the performance of a biological nanopore is dependent on the protein in the channel structure its dimensions are predetermined and are difficult to modify for broader applications. Here inspired by the cytotoxic mechanisms of a saponin derivative, alpha-hederin, we report a nonproteinaceous nanopore that can be formed spontaneously in a lipid membrane. We propose the pore-forming mechanism of alpha-hederin in a cholesterol-rich lipid membrane and a strategy to control the pore-forming rate by a lipid partitioning method. The small diameter and effective thickness of alpha-hederin nanopores enabled us to discriminate ssDNA homopolymers as well as four types of nucleotides, showing its potential as a DNA sequencing tool.
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Affiliation(s)
- Ki-Baek Jeong
- Graduate School of Biotechnology and Department of Food Science and Biotechnology , Kyung Hee University , Yongin 17104 , Republic of Korea
| | - Ke Luo
- Graduate School of Biotechnology and Department of Food Science and Biotechnology , Kyung Hee University , Yongin 17104 , Republic of Korea
| | - Hwankyu Lee
- Department of Chemical Engineering , Dankook University , Yongin 16891 , Republic of Korea
| | - Min-Cheol Lim
- Research Group of Food Safety , Korea Food Research Institute , 245, Nongsaengmyeong-ro , Iseo-myeon, Wanju-gun , Jeollabuk-do 55365 , Republic of Korea
| | - Jin Yu
- Department of Applied Food System, Major of Food Science & Technology , Seoul Women's University , Seoul 01797 , Republic of Korea
| | - Soo-Jin Choi
- Department of Applied Food System, Major of Food Science & Technology , Seoul Women's University , Seoul 01797 , Republic of Korea
| | - Ki-Bum Kim
- Department of Materials Science and Engineering , Seoul National University , Seoul 08826 , Republic of Korea
| | - Tae-Joon Jeon
- Department of Biological Engineering , Inha University , Incheon 22212 , Republic of Korea
| | - Young-Rok Kim
- Graduate School of Biotechnology and Department of Food Science and Biotechnology , Kyung Hee University , Yongin 17104 , Republic of Korea
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Abbasi F, Alvarez-Malmagro J, Su Z, Leitch JJ, Lipkowski J. Pore Forming Properties of Alamethicin in Negatively Charged Floating Bilayer Lipid Membranes Supported on Gold Electrodes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13754-13765. [PMID: 30265810 DOI: 10.1021/acs.langmuir.8b02554] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), and photon polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) were employed to investigate the formation of alamethicin pores in negatively charged bilayers composed of a mixture of 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) and egg-PG floating at gold (111) electrode surfaces modified by self-assembled monolayers of 1-thio-β-d-glucose (β-Tg). The EIS data showed that the presence of alamethicin decreases the membrane resistivity by about 1 order of magnitude. PM-IRRAS measurements provided information about the tilt angles of peptide helical axis with respect to the bilayer normal. The small tilt angles obtained for the peptide helical axis prove that the alamethicin molecules were inserted into the DMPC/egg-PG membranes. The tilt angles decreased when negative potentials were applied, which correlates with the observed decrease in membrane resistivity, indicating that ion pore formation is assisted by the transmembrane potential. Molecular resolution AFM images provided visual evidence that alamethicin molecules aggregate forming hexagonal porous 2D lattices with periodicities of 2.0 ± 0.2 nm. The pore formation by alamethicin in the negatively charged membrane was compared with the interaction of this peptide with a bilayer formed by zwitterionic lipids. The comparison of these results showed that alamethicin preferentially forms ion translocating pores in negatively charged phospholipid membranes.
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Affiliation(s)
- Fatemeh Abbasi
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | | | - ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - J Jay Leitch
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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36
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Goronzy DP, Ebrahimi M, Rosei F, Fang Y, De Feyter S, Tait SL, Wang C, Beton PH, Wee ATS, Weiss PS, Perepichka DF. Supramolecular Assemblies on Surfaces: Nanopatterning, Functionality, and Reactivity. ACS NANO 2018; 12:7445-7481. [PMID: 30010321 DOI: 10.1021/acsnano.8b03513] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Understanding how molecules interact to form large-scale hierarchical structures on surfaces holds promise for building designer nanoscale constructs with defined chemical and physical properties. Here, we describe early advances in this field and highlight upcoming opportunities and challenges. Both direct intermolecular interactions and those that are mediated by coordinated metal centers or substrates are discussed. These interactions can be additive, but they can also interfere with each other, leading to new assemblies in which electrical potentials vary at distances much larger than those of typical chemical interactions. Earlier spectroscopic and surface measurements have provided partial information on such interfacial effects. In the interim, scanning probe microscopies have assumed defining roles in the field of molecular organization on surfaces, delivering deeper understanding of interactions, structures, and local potentials. Self-assembly is a key strategy to form extended structures on surfaces, advancing nanolithography into the chemical dimension and providing simultaneous control at multiple scales. In parallel, the emergence of graphene and the resulting impetus to explore 2D materials have broadened the field, as surface-confined reactions of molecular building blocks provide access to such materials as 2D polymers and graphene nanoribbons. In this Review, we describe recent advances and point out promising directions that will lead to even greater and more robust capabilities to exploit designer surfaces.
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Affiliation(s)
- Dominic P Goronzy
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Chemistry and Biochemistry , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Maryam Ebrahimi
- INRS Centre for Energy, Materials and Telecommunications , 1650 Boul. Lionel Boulet , Varennes , Quebec J3X 1S2 , Canada
| | - Federico Rosei
- INRS Centre for Energy, Materials and Telecommunications , 1650 Boul. Lionel Boulet , Varennes , Quebec J3X 1S2 , Canada
- Institute for Fundamental and Frontier Science , University of Electronic Science and Technology of China , Chengdu 610054 , P.R. China
| | - Yuan Fang
- Department of Chemistry , McGill University , Montreal H3A 0B8 , Canada
| | - Steven De Feyter
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Steven L Tait
- Department of Chemistry , Indiana University , Bloomington , Indiana 47405 , United States
| | - Chen Wang
- National Center for Nanoscience and Technology , Beijing 100190 , China
| | - Peter H Beton
- School of Physics & Astronomy , University of Nottingham , Nottingham NG7 2RD , United Kingdom
| | - Andrew T S Wee
- Department of Physics , National University of Singapore , 117542 Singapore
| | - Paul S Weiss
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Chemistry and Biochemistry , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Materials Science and Engineering , University of California, Los Angeles , Los Angeles , California 90095 , United States
| | - Dmitrii F Perepichka
- California NanoSystems Institute , University of California, Los Angeles , Los Angeles , California 90095 , United States
- Department of Chemistry , McGill University , Montreal H3A 0B8 , Canada
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Hyporientalin A, an anti-Candida peptaibol from a marine Trichoderma orientale. World J Microbiol Biotechnol 2018; 34:98. [PMID: 29922855 DOI: 10.1007/s11274-018-2482-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/14/2018] [Indexed: 10/28/2022]
Abstract
A Trichoderma orientale strain LSBA1 was isolated from the Mediterranean marine sponge Cymbaxinella damicornis. The crude extract of T. orientale mycelium showed inhibitory activity against growth of Gram-positive and Gram-negative bacteria as well as clinical isolates of Candida albicans. Purification of the anti-Candida component was performed using a combination of open silica gel-60 column and reverse phase high performance liquid chromatography. The active compound called hyporientalin A has been identified as a peptaibol analogue of longibrachin-A-II using mass spectrometry. It exhibited fungicidal activity against clinical isolates of C. albicans with minimal inhibitory concentrations (MICs) ranging from 2.49 to 19.66 µM, comparable to that of the antifungal agent amphotericin B. Our data support the use of hyporientalin A as a promising new and efficient antifungal drug in the treatment of candidiasis while controlling toxicity.
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Su Z, Shodiev M, Jay Leitch J, Abbasi F, Lipkowski J. In situ electrochemical and PM-IRRAS studies of alamethicin ion channel formation in model phospholipid bilayers. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2017.10.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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39
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Su Z, Shodiev M, Leitch JJ, Abbasi F, Lipkowski J. Role of Transmembrane Potential and Defects on the Permeabilization of Lipid Bilayers by Alamethicin, an Ion-Channel-Forming Peptide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:6249-6260. [PMID: 29722994 DOI: 10.1021/acs.langmuir.8b00928] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The insertion and ion-conducting channel properties of alamethicin reconstituted into a 1,2-di- O-phytanyl- sn-glycero-3-phosphocholine bilayer floating on the surface of a gold (111) electrode modified with a 1-thio-β-d-glucose (β-Tg) self-assembled monolayer were investigated using a combination of electrochemical impedance spectroscopy (EIS) and polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). The hydrophilic β-Tg monolayer separated the bilayer from the gold substrate and created a water-rich spacer region, which better represents natural cell membranes. The EIS measurements acquired information about the membrane resistivity (a measure of membrane porosity), and the PM-IRRAS experiments provided insight into the conformation and orientation of the membrane constituents as a function of the transmembrane potential. The results showed that the presence of alamethicin had a small effect on the conformation and orientation of phospholipid molecules within the bilayer for all studied potentials. In contrast, the alamethicin peptides assumed a surface state, where the helical axes adopted a large tilt angle with respect to the surface normal, at small transmembrane potentials, and inserted into the bilayer at sufficiently negative transmembrane potentials forming pores, which behaved as barrel-stave ion channels for ionic transport across the membrane. The results indicated that insertion of alamethincin peptides into the bilayer was driven by the dipole-field interactions and that the transitions between the inserted and surface states were electrochemically reversible. Additionally, the EIS measurements performed on phospholipid bilayers without alamethicin also showed that the application of negative transmembrane potentials introduces defects into the bilayer. The membrane resistances measured in both the absence and presence of alamethicin show similar dependencies on the electrode potential, suggesting that the insertion of the peptide may also be assisted by the electroporation of the membrane. The findings in this study provide new insights into the mechanism of alamethicin insertion into phospholipid bilayers.
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Affiliation(s)
- ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Muzaffar Shodiev
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - J Jay Leitch
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Fatemeh Abbasi
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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Abbasi F, Leitch JJ, Su Z, Szymanski G, Lipkowski J. Direct visualization of alamethicin ion pores formed in a floating phospholipid membrane supported on a gold electrode surface. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.02.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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41
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EIS and PM-IRRAS studies of alamethicin ion channels in a tethered lipid bilayer. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2017.12.039] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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42
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Forbrig E, Staffa JK, Salewski J, Mroginski MA, Hildebrandt P, Kozuch J. Monitoring the Orientational Changes of Alamethicin during Incorporation into Bilayer Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2373-2385. [PMID: 29353482 DOI: 10.1021/acs.langmuir.7b04265] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Antimicrobial peptides (AMPs) are the first line of defense after contact of an infectious invader, for example, bacterium or virus, with a host and an integral part of the innate immune system of humans. Their broad spectrum of biological functions ranges from cell membrane disruption over facilitation of chemotaxis to interaction with membrane-bound or intracellular receptors, thus providing novel strategies to overcome bacterial resistances. Especially, the clarification of the mechanisms and dynamics of AMP incorporation into bacterial membranes is of high interest, and different mechanistic models are still under discussion. In this work, we studied the incorporation of the peptaibol alamethicin (ALM) into tethered bilayer lipid membranes on electrodes in combination with surface-enhanced infrared absorption (SEIRA) spectroscopy. This approach allows monitoring the spontaneous and potential-induced ion channel formation of ALM in situ. The complex incorporation kinetics revealed a multistep mechanism that points to peptide-peptide interactions prior to penetrating the membrane and adopting the transmembrane configuration. On the basis of the anisotropy of the backbone amide I and II infrared absorptions determined by density functional theory calculations, we employed a mathematical model to evaluate ALM reorientations monitored by SEIRA spectroscopy. Accordingly, ALM was found to adopt inclination angles of ca. 69°-78° and 21° in its interfacially adsorbed and transmembrane incorporated states, respectively. These orientations can be stabilized efficiently by the dipolar interaction with lipid head groups or by the application of a potential gradient. The presented potential-controlled mechanistic study suggests an N-terminal integration of ALM into membranes as monomers or parallel oligomers to form ion channels composed of parallel-oriented helices, whereas antiparallel oligomers are barred from intrusion.
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Affiliation(s)
- Enrico Forbrig
- Technische Universität Berlin, Institut für Chemie , Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
| | - Jana K Staffa
- Technische Universität Berlin, Institut für Chemie , Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
| | - Johannes Salewski
- Technische Universität Berlin, Institut für Chemie , Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
| | - Maria Andrea Mroginski
- Technische Universität Berlin, Institut für Chemie , Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie , Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
| | - Jacek Kozuch
- Technische Universität Berlin, Institut für Chemie , Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
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Divakaruni AS, Andreyev AY, Rogers GW, Murphy AN. In situ measurements of mitochondrial matrix enzyme activities using plasma and mitochondrial membrane permeabilization agents. Anal Biochem 2017; 552:60-65. [PMID: 28987935 DOI: 10.1016/j.ab.2017.09.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/27/2017] [Accepted: 09/29/2017] [Indexed: 12/16/2022]
Abstract
Activities of enzymes localized to the mitochondrial matrix of mammalian cells are often critical regulatory steps in cellular metabolism. As such, measurement of matrix enzyme activities in response to genetic modifications or drug interventions is often desired. However, measurements in intact cells are often hampered by the presence of other isozymes in the cytoplasm as well as the inability to deliver enzyme substrates across cellular membranes. Classic approaches to liberate matrix enzymes utilize harsh treatments that disrupt intracellular architecture or require significant starting material to allow mitochondrial isolation prior to sample extraction. We describe a method using permeabilization reagents for both the plasma and mitochondrial membranes to allow in situ measurement of matrix enzyme activities. It is applied to adherent cell monolayers in 96-well plates treated with perfringolysin O to permeabilize the plasma membrane and alamethicin to permeabilize the mitochondrial inner membrane. We present three examples validated with inhibitor sensitivity: (i) Complex I-mediated oxygen consumption driven by NADH, (ii) ATP hydrolysis by the F1FO complex measuring pH changes in an Agilent Seahorse XF Analyzer, and (iii) Mitochondrial glutaminase (GLS1) activity in a coupled reaction monitoring NADH fluorescence in a plate reader.
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Affiliation(s)
- Ajit S Divakaruni
- University of California, Los Angeles, Department of Molecular and Medical Pharmacology, 650 Charles E. Young Dr. South, 23-305 Center for Health Sciences, Los Angeles, CA 90095-1735, United States.
| | - Alexander Y Andreyev
- University of California, San Diego, Department of Pharmacology, 9500 Gilman Drive #0636, La Jolla, CA 92093, United States
| | - George W Rogers
- Agilent Technologies, 5301 Stevens Creek Blvd, Santa Clara, CA 95051, United States
| | - Anne N Murphy
- University of California, San Diego, Department of Pharmacology, 9500 Gilman Drive #0636, La Jolla, CA 92093, United States
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Fennouri A, Mayer SF, Schroeder TBH, Mayer M. Single channel planar lipid bilayer recordings of the melittin variant MelP5. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:2051-2057. [PMID: 28720433 DOI: 10.1016/j.bbamem.2017.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/27/2017] [Accepted: 07/07/2017] [Indexed: 12/26/2022]
Abstract
MelP5 is a 26 amino acid peptide derived from melittin, the main active constituent of bee venom, with five amino acid replacements. The pore-forming activity of MelP5 in lipid membranes is attracting attention because MelP5 forms larger pores and induces dye leakage through liposome membranes at a lower concentration than melittin. Studies of MelP5 have so far focused on ensemble measurements of membrane leakage and impedance; here we extend this characterization with an electrophysiological comparison between MelP5 and melittin using planar lipid bilayer recordings. These experiments reveal that MelP5 pores in lipid membranes composed of 3:1 phosphatidylcholine:cholesterol consist of an average of 10 to 12 monomers compared to an average of 3 to 9 monomers for melittin. Both peptides form transient pores with dynamically varying conductance values similar to previous findings for melittin, but MelP5 occasionally also forms stable, well-defined pores with single channel conductance values that vary greatly and range from 50 to 3000pS in an electrolyte solution containing 100mM KCl.
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Affiliation(s)
- Aziz Fennouri
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland
| | - Simon Finn Mayer
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland; Biberach University of Applied Sciences, Karlstraße 11, 88400 Biberach, Germany
| | - Thomas B H Schroeder
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland; Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, United States
| | - Michael Mayer
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700 Fribourg, Switzerland.
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45
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Howorka S. Building membrane nanopores. NATURE NANOTECHNOLOGY 2017; 12:619-630. [PMID: 28681859 DOI: 10.1038/nnano.2017.99] [Citation(s) in RCA: 188] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 04/19/2017] [Indexed: 05/28/2023]
Abstract
Membrane nanopores-hollow nanoscale barrels that puncture biological or synthetic membranes-have become powerful tools in chemical- and biosensing, and have achieved notable success in portable DNA sequencing. The pores can be self-assembled from a variety of materials, including proteins, peptides, synthetic organic compounds and, more recently, DNA. But which building material is best for which application, and what is the relationship between pore structure and function? In this Review, I critically compare the characteristics of the different building materials, and explore the influence of the building material on pore structure, dynamics and function. I also discuss the future challenges of developing nanopore technology, and consider what the next-generation of nanopore structures could be and where further practical applications might emerge.
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Affiliation(s)
- Stefan Howorka
- Department of Chemistry, Institute of Structural Molecular Biology, University College London, London WC1H 0AJ, UK
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Henderson JM, Waring AJ, Separovic F, Lee KYC. Antimicrobial Peptides Share a Common Interaction Driven by Membrane Line Tension Reduction. Biophys J 2017; 111:2176-2189. [PMID: 27851941 DOI: 10.1016/j.bpj.2016.10.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/30/2016] [Accepted: 10/05/2016] [Indexed: 12/30/2022] Open
Abstract
Antimicrobial peptides (AMPs) are a class of host-defense molecules that neutralize a broad range of pathogens. Their membrane-permeabilizing behavior has been commonly attributed to the formation of pores; however, with the continuing discovery of AMPs, many are uncharacterized and their exact mechanism remains unknown. Using atomic force microscopy, we previously characterized the disruption of model membranes by protegrin-1 (PG-1), a cationic AMP from pig leukocytes. When incubated with zwitterionic membranes of dimyristoylphosphocholine, PG-1 first induced edge instability at low concentrations, then porous defects at intermediate concentrations, and finally worm-like micelle structures at high concentrations. These rich structural changes suggested that pore formation constitutes only an intermediate state along the route of PG-1's membrane disruption process. The formation of these structures could be best understood by using a mesophase framework of a binary mixture of lipids and peptides, where PG-1 acts as a line-active agent in lowering interfacial bilayer tensions. We have proposed that rather than being static pore formers, AMPs share a common ability to lower interfacial tensions that promote membrane transformations. In a study of 13 different AMPs, we found that peptide line-active behavior was not driven by the overall charge, and instead was correlated with their adoption of imperfect secondary structures. These peptide structures commonly positioned charged residues near the membrane interface to promote deformation favorable for their incorporation into the membrane. Uniquely, the data showed that barrel-stave-forming peptides such as alamethicin are not line-active, and that the seemingly disparate models of toroidal pores and carpet activity are actually related. We speculate that this interplay between peptide structure and the distribution of polar residues in relation to the membrane governs AMP line activity in general and represents a novel, to our knowledge, avenue for the rational design of new drugs.
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Affiliation(s)
- J Michael Henderson
- Department of Chemistry, The University of Chicago, Chicago, Illinois; Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois; The James Frank Institute, The University of Chicago, Chicago, Illinois
| | - Alan J Waring
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California; Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Ka Yee C Lee
- Department of Chemistry, The University of Chicago, Chicago, Illinois; Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois; The James Frank Institute, The University of Chicago, Chicago, Illinois.
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Malanovic N, Lohner K. Antimicrobial Peptides Targeting Gram-Positive Bacteria. Pharmaceuticals (Basel) 2016; 9:E59. [PMID: 27657092 PMCID: PMC5039512 DOI: 10.3390/ph9030059] [Citation(s) in RCA: 219] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 01/01/2023] Open
Abstract
Antimicrobial peptides (AMPs) have remarkably different structures as well as biological activity profiles, whereupon most of these peptides are supposed to kill bacteria via membrane damage. In order to understand their molecular mechanism and target cell specificity for Gram-positive bacteria, it is essential to consider the architecture of their cell envelopes. Before AMPs can interact with the cytoplasmic membrane of Gram-positive bacteria, they have to traverse the cell wall composed of wall- and lipoteichoic acids and peptidoglycan. While interaction of AMPs with peptidoglycan might rather facilitate penetration, interaction with anionic teichoic acids may act as either a trap for AMPs or a ladder for a route to the cytoplasmic membrane. Interaction with the cytoplasmic membrane frequently leads to lipid segregation affecting membrane domain organization, which affects membrane permeability, inhibits cell division processes or leads to delocalization of essential peripheral membrane proteins. Further, precursors of cell wall components, especially the highly conserved lipid II, are directly targeted by AMPs. Thereby, the peptides do not inhibit peptidoglycan synthesis via binding to proteins like common antibiotics, but form a complex with the precursor molecule, which in addition can promote pore formation and membrane disruption. Thus, the multifaceted mode of actions will make AMPs superior to antibiotics that act only on one specific target.
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Affiliation(s)
- Nermina Malanovic
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, NAWI Graz, Austria.
- BioTechMed Graz, Humboldtstrasse 50/III, 8010 Graz, Austria.
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Shimizu H, Matsunaga S, Yamada T, Kobayashi T, Kawai M. Formation of Ordered Phospholipid Monolayer on a Hydrophilically Modified Au(111) Substrate. ACS NANO 2016; 10:7811-7820. [PMID: 27494363 DOI: 10.1021/acsnano.6b03421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The molecular arrangement of phospholipid molecules was investigated on a hydrophilically modified gold surface within an aqueous solution by scanning tunneling microscopy. By suspending phospholipid (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, POPC) nanoparticles in the aqueous electrolyte surrounding a hydrophilically modified gold (111) substrate with 3-mercaptopropionic acid (SH-C2H4-COOH, 3-MPA), well-ordered adlattices of POPC were observed. Traces of particle fusion were visualized before formation of the adlattice. Addition of cholesterol to the suspension seems to facilitate accommodation of POPC on this surface. The observed unit cells of POPC adlattices had dimensions of 0.5 nm × 1.9-2.5 nm. By high-resolution imaging, each unit cell was discerned to be occupied by one upright POPC molecule. The POPC + cholesterol suspension also leads to formation of a flat integrated POPC layer, which may be a lipid bilayer covering the surface.
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Affiliation(s)
- Hiroaki Shimizu
- RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Soichiro Matsunaga
- RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Taro Yamada
- RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | - Maki Kawai
- RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Advanced Materials Science, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
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Interaction of Cecropin B with Zwitterionic and Negatively Charged Lipid Bilayers Immobilized at Gold Electrode Surface. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.04.080] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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50
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Juhaniewicz J, Sek S. Interaction of Melittin with Negatively Charged Lipid Bilayers Supported on Gold Electrodes. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2015.11.134] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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