1
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Schaefer KG, Russell CM, Pyron RJ, Conley EA, Barrera FN, King GM. Polymerization mechanism of the Candida albicans virulence factor candidalysin. J Biol Chem 2024; 300:107370. [PMID: 38750794 PMCID: PMC11193009 DOI: 10.1016/j.jbc.2024.107370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/16/2024] [Accepted: 05/06/2024] [Indexed: 06/11/2024] Open
Abstract
Candida albicans is a commensal fungus that can cause epithelial infections and life-threatening invasive candidiasis. The fungus secretes candidalysin (CL), a peptide that causes cell damage and immune activation by permeation of epithelial membranes. The mechanism of CL action involves strong peptide assembly into polymers in solution. The free ends of linear CL polymers can join, forming loops that become pores upon binding to membranes. CL polymers constitute a therapeutic target for candidiasis, but little is known about CL self-assembly in solution. Here, we examine the assembly mechanism of CL in the absence of membranes using complementary biophysical tools, including a new fluorescence polymerization assay, mass photometry, and atomic force microscopy. We observed that CL assembly is slow, as tracked with the fluorescent marker C-laurdan. Single-molecule methods showed that CL polymerization involves a convolution of four processes. Self-assembly begins with the formation of a basic subunit, thought to be a CL octamer that is the polymer seed. Polymerization proceeds via the addition of octamers, and as polymers grow they can curve and form loops. Alternatively, secondary polymerization can occur and cause branching. Interplay between the different rates determines the distribution of CL particle types, indicating a kinetic control mechanism. This work elucidates key physical attributes underlying CL self-assembly which may eventually evoke pharmaceutical development.
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Affiliation(s)
| | - Charles M Russell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Robert J Pyron
- Genome Science and Technology, University of Tennessee, Knoxville, Tennessee
| | - Elizabeth A Conley
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee.
| | - Gavin M King
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri; Department of Biochemistry, University of Missouri, Columbia, Missouri.
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2
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Walsh OD, Choi L, Sigdel KP. Effect of CM15 on Supported Lipid Bilayer Probed by Atomic Force Microscopy. MEMBRANES 2023; 13:864. [PMID: 37999350 PMCID: PMC10672887 DOI: 10.3390/membranes13110864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023]
Abstract
Antimicrobial peptides are key components of the immune system. These peptides affect the membrane in various ways; some form nano-sized pores, while others only produce minor defects. Since these peptides are increasingly important in developing antimicrobial drugs, understanding the mechanism of their interactions with lipid bilayers is critical. Here, using atomic force microscopy (AFM), we investigated the effect of a synthetic hybrid peptide, CM15, on the membrane surface comprising E. coli polar lipid extract. Direct imaging of supported lipid bilayers exposed to various concentrations of the peptide revealed significant membrane remodeling. We found that CM15 interacts with supported lipid bilayers and forms membrane-spanning defects very quickly. It is found that CM15 is capable of remodeling both leaflets of the bilayer. For lower CM15 concentrations, punctate void-like defects were observed, some of which re-sealed themselves as a function of time. However, for CM15 concentrations higher than 5 µM, the defects on the bilayers became so widespread that they disrupted the membrane integrity completely. This work enhances the understanding of CM15 interactions with the bacterial lipid bilayer.
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Affiliation(s)
| | | | - Krishna P. Sigdel
- Department of Physics and Astronomy, California State Polytechnic University, Pomona, CA 91768, USA
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3
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Chen EHL, Wang CH, Liao YT, Chan FY, Kanaoka Y, Uchihashi T, Kato K, Lai L, Chang YW, Ho MC, Chen RPY. Visualizing the membrane disruption action of antimicrobial peptides by cryo-electron tomography. Nat Commun 2023; 14:5464. [PMID: 37673860 PMCID: PMC10482868 DOI: 10.1038/s41467-023-41156-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/24/2023] [Indexed: 09/08/2023] Open
Abstract
The abuse of antibiotics has led to the emergence of multidrug-resistant microbial pathogens, presenting a pressing challenge in global healthcare. Membrane-disrupting antimicrobial peptides (AMPs) combat so-called superbugs via mechanisms different than conventional antibiotics and have good application prospects in medicine, agriculture, and the food industry. However, the mechanism-of-action of AMPs has not been fully characterized at the cellular level due to a lack of high-resolution imaging technologies that can capture cellular-membrane disruption events in the hydrated state. Previously, we reported PepD2M, a de novo-designed AMP with potent and wide-spectrum bactericidal and fungicidal activity. In this study, we use cryo-electron tomography (cryo-ET) and high-speed atomic force microscopy (HS-AFM) to directly visualize the pepD2M-induced disruption of the outer and inner membranes of the Gram-negative bacterium Escherichia coli, and compared with a well-known pore-forming peptide, melittin. Our high-resolution cryo-ET images reveal how pepD2M disrupts the E. coli membrane using a carpet/detergent-like mechanism. Our studies reveal the direct membrane-disrupting consequence of AMPs on the bacterial membrane by cryo-ET, and this information provides critical insights into the mechanisms of this class of antimicrobial agents.
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Affiliation(s)
- Eric H-L Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Yi-Ting Liao
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Feng-Yueh Chan
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - Yui Kanaoka
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - Takayuki Uchihashi
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
- Institute for Glyco-core Research (iGCORE), Nagoya University, Nagoya, 464-8602, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Longsheng Lai
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6059, USA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104-6059, USA
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, 100, Taiwan.
| | - Rita P-Y Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
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4
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Maffeis V, Hürlimann D, Krywko-Cendrowska A, Schoenenberger CA, Housecroft CE, Palivan CG. A DNA-Micropatterned Surface for Propagating Biomolecular Signals by Positional on-off Assembly of Catalytic Nanocompartments. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2202818. [PMID: 35869606 DOI: 10.1002/smll.202202818] [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: 05/06/2022] [Revised: 06/17/2022] [Indexed: 06/15/2023]
Abstract
Signal transduction is pivotal for the transfer of information between and within living cells. The composition and spatial organization of specified compartments are key to propagating soluble signals. Here, a high-throughput platform mimicking multistep signal transduction which is based on a geometrically defined array of immobilized catalytic nanocompartments (CNCs) that consist of distinct polymeric nanoassemblies encapsulating enzymes and DNA or enzymes alone is presented. The dual role of single entities or tandem CNCs in providing confined but communicating spaces for complex metabolic reactions and in protecting encapsulated compounds from denaturation is explored. To support a controlled spatial organization of CNCs, CNCs are patterned by means of DNA hybridization to a microprinted glass surface. Specifically, CNC-functionalized DNA microarrays are produced where individual reaction compartments are kept in close proximity by a distinct geometrical arrangement to promote effective communication. Besides a remarkable versatility and robustness, the most prominent feature of this platform is the reversibility of DNA-mediated CNC-anchoring which renders it reusable. Micropatterns of polymer-based nanocompartment assemblies offer an ideal scaffold for the development of the next generation responsive and communicative soft-matter analytical devices for applications in catalysis and medicine.
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Affiliation(s)
- Viviana Maffeis
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Dimitri Hürlimann
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Agata Krywko-Cendrowska
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
| | - Cora-Ann Schoenenberger
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Catherine E Housecroft
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, Mattenstrasse 24a, BPR 1096, Basel, 4058, Switzerland
- NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, Basel, CH-4058, Switzerland
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5
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Russell CM, Schaefer KG, Dixson A, Gray ALH, Pyron RJ, Alves DS, Moore N, Conley EA, Schuck RJ, White TA, Do TD, King GM, Barrera FN. The Candida albicans virulence factor candidalysin polymerizes in solution to form membrane pores and damage epithelial cells. eLife 2022; 11:e75490. [PMID: 36173096 PMCID: PMC9522247 DOI: 10.7554/elife.75490] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 08/15/2022] [Indexed: 11/28/2022] Open
Abstract
Candida albicans causes severe invasive candidiasis. C. albicans infection requires the virulence factor candidalysin (CL) which damages target cell membranes. However, the mechanism that CL uses to permeabilize membranes is unclear. We reveal that CL forms membrane pores using a unique mechanism. Unexpectedly, CL readily assembled into polymers in solution. We propose that the basic structural unit in polymer formation is a CL oligomer, which is sequentially added into a string configuration that can close into a loop. CL loops appear to spontaneously insert into the membrane to become pores. A CL mutation (G4W) inhibited the formation of polymers in solution and prevented pore formation in synthetic lipid systems. Epithelial cell studies showed that G4W CL failed to activate the danger response pathway, a hallmark of the pathogenic effect of CL. These results indicate that CL polymerization in solution is a necessary step for the damage of cellular membranes. Analysis of CL pores by atomic force microscopy revealed co-existence of simple depressions and more complex pores, which are likely formed by CL assembled in an alternate oligomer orientation. We propose that this structural rearrangement represents a maturation mechanism that stabilizes pore formation to achieve more robust cellular damage. To summarize, CL uses a previously unknown mechanism to damage membranes, whereby pre-assembly of CL loops in solution leads to formation of membrane pores. Our investigation not only unravels a new paradigm for the formation of membrane pores, but additionally identifies CL polymerization as a novel therapeutic target to treat candidiasis.
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Affiliation(s)
- Charles M Russell
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | - Katherine G Schaefer
- Department of Physics and Astronomy, University of MissouriColumbiaUnited States
| | - Andrew Dixson
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | - Amber LH Gray
- Department of Chemistry, University of TennesseeKnoxvilleUnited States
| | - Robert J Pyron
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | - Daiane S Alves
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | - Nicholas Moore
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | - Elizabeth A Conley
- Department of Physics and Astronomy, University of MissouriColumbiaUnited States
| | - Ryan J Schuck
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
| | - Tommi A White
- Department of Biochemistry, University of MissouriColumbiaUnited States
- Electron Microscopy Core, University of MissouriColumbiaUnited States
| | - Thanh D Do
- Department of Chemistry, University of TennesseeKnoxvilleUnited States
| | - Gavin M King
- Department of Physics and Astronomy, University of MissouriColumbiaUnited States
- Department of Biochemistry, University of MissouriColumbiaUnited States
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of TennesseeKnoxvilleUnited States
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6
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Schaefer KG, Pittman AE, Barrera FN, King GM. Atomic force microscopy for quantitative understanding of peptide-induced lipid bilayer remodeling. Methods 2022; 197:20-29. [PMID: 33164792 DOI: 10.1016/j.ymeth.2020.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 12/15/2022] Open
Abstract
A number of peptides are known to bind lipid bilayer membranes and cause these natural barriers to leak in an uncontrolled manner. Though membrane permeabilizing peptides play critical roles in cellular activity and may have promising future applications in the therapeutic arena, significant questions remain about their mechanisms of action. The atomic force microscope (AFM) is a single molecule imaging tool capable of addressing lipid bilayers in near-native fluid conditions. The apparatus complements traditional assays by providing local topographic maps of bilayer remodeling induced by membrane permeabilizing peptides. The information garnered from the AFM includes direct visualization and statistical analyses of distinct bilayer remodeling modes such as highly localized pore-like voids in the bilayer and dispersed thinned membrane regions. Colocalization of distinct remodeling modes can be studied. Here we examine recent work in the field and outline methods used to achieve precise AFM image data. Experimental challenges and common pitfalls are discussed as well as techniques for unbiased analysis including the Hessian blob detection algorithm, bootstrapping, and the Bayesian information criterion. When coupled with robust statistical analyses, high precision AFM data is poised to advance understanding of an important family of peptides that cause poration of membrane bilayers.
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Affiliation(s)
- K G Schaefer
- Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211, USA
| | - A E Pittman
- Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211, USA
| | - F N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - G M King
- Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211, USA; Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.
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7
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Schaefer KG, Grau B, Moore N, Mingarro I, King GM, Barrera FN. Controllable membrane remodeling by a modified fragment of the apoptotic protein Bax. Faraday Discuss 2021; 232:114-130. [PMID: 34549736 PMCID: PMC8712456 DOI: 10.1039/d0fd00070a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intrinsic apoptosis is orchestrated by a group of proteins that mediate the coordinated disruption of mitochondrial membranes. Bax is a multi-domain protein that, upon activation, disrupts the integrity of the mitochondrial outer membrane by forming pores. We strategically introduced glutamic acids into a short sequence of the Bax protein that constitutively creates membrane pores. The resulting BaxE5 peptide efficiently permeabilizes membranes at acidic pH, showing low permeabilization at neutral pH. Atomic force microscopy (AFM) imaging showed that at acidic pH BaxE5 established several membrane remodeling modalities that progressively disturbed the integrity of the lipid bilayer. The AFM data offers vistas on the membrane disruption process, which starts with pore formation and progresses through localized exposure of membrane monolayers leading to stable and small (height ∼ 16 Å) lipid-peptide complexes. The different types of membrane morphology observed in the presence of BaxE5 suggest that the peptide can establish different types of membrane interactions. BaxE5 adopts a rare unstructured conformation when bound to membranes, which might facilitate the dynamic transition between those different states, and then promote membrane digestion.
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Affiliation(s)
- Katherine G Schaefer
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
| | - Brayan Grau
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, 37996, USA.
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46100 Burjassot, Spain
| | - Nicolas Moore
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, 37996, USA.
| | - Ismael Mingarro
- Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46100 Burjassot, Spain
| | - Gavin M King
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA.
- Department of Biochemistry, University of Missouri, Columbia, Missouri, 65211, USA
| | - Francisco N Barrera
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, 37996, USA.
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8
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Nasompag S, Siritongsuk P, Thammawithan S, Srichaiyapol O, Prangkio P, Camesano TA, Sinthuvanich C, Patramanon R. AFM Study of Nanoscale Membrane Perturbation Induced by Antimicrobial Lipopeptide C 14 KYR. MEMBRANES 2021; 11:membranes11070495. [PMID: 34208993 PMCID: PMC8307486 DOI: 10.3390/membranes11070495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022]
Abstract
Lipopeptides have been extensively studied as potential antimicrobial agents. In this study, we focused on the C14-KYR lipopeptide, a modified version of the KYR tripeptide with myristic acid at the N-terminus. Here, membrane perturbation of live E. coli treated with the parent KYR and C14-KYR peptides was compared at the nanoscale level using AFM imaging. AFM analyses, including average cellular roughness and force spectroscopy, revealed the severe surface disruption mechanism of C14-KYR. A loss of surface roughness and changes in topographic features included membrane shrinkage, periplasmic membrane separation from the cell wall, and cytosolic leakage. Additional evidence from synchrotron radiation FTIR microspectroscopy (SR-FTIR) revealed a marked structural change in the membrane component after lipopeptide attack. The average roughness of the E. coli cell before and after treatment with C14-KYR was 129.2 ± 51.4 and 223.5 ± 14.1 nm, respectively. The average rupture force of the cell treated with C14-KYR was 0.16 nN, four times higher than that of the untreated cell. Our study demonstrates that the mechanistic effect of the lipopeptide against bacterial cells can be quantified through surface imaging and adhesion force using AFM.
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Affiliation(s)
- Sawinee Nasompag
- Interdisciplinary Graduate Program in Genetic Engineering, The Graduate School, Kasetsart University, Bangkok 10900, Thailand; (S.N.); (C.S.)
| | - Pawinee Siritongsuk
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; (P.S.); (S.T.); (O.S.)
| | - Saengrawee Thammawithan
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; (P.S.); (S.T.); (O.S.)
| | - Oranee Srichaiyapol
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; (P.S.); (S.T.); (O.S.)
| | - Panchika Prangkio
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand;
| | - Terri A. Camesano
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA;
| | - Chomdao Sinthuvanich
- Interdisciplinary Graduate Program in Genetic Engineering, The Graduate School, Kasetsart University, Bangkok 10900, Thailand; (S.N.); (C.S.)
- Department of Biochemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand
| | - Rina Patramanon
- Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand; (P.S.); (S.T.); (O.S.)
- Correspondence:
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9
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Hammond K, Benn G, Bennett I, Parsons ES, Ryadnov MG, Hoogenboom BW, Pyne ALB. Imaging the Effects of Peptide Materials on Phospholipid Membranes by Atomic Force Microscopy. Methods Mol Biol 2021; 2208:225-235. [PMID: 32856266 DOI: 10.1007/978-1-0716-0928-6_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recent advances in biomolecular design require accurate measurements performed in native or near-native environments in real time. Atomic force microscopy (AFM) is a powerful tool to observe the dynamics of biologically relevant processes at aqueous interfaces with high spatial resolution. Here, we describe imaging protocols to characterize the effects of peptide materials on phospholipid membranes in solution by AFM. These protocols can be used to determine the mechanism and kinetics of membrane-associated activities at the nanoscale.
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Affiliation(s)
- Katharine Hammond
- London Centre for Nanotechnology, University College London, London, UK
- National Physical Laboratory, Teddington, UK
- Department of Physics and Astronomy, University College London, London, UK
| | - Georgina Benn
- London Centre for Nanotechnology, University College London, London, UK
- National Physical Laboratory, Teddington, UK
- Institute of Structural and Molecular Biology, University College London, London, UK
| | - Isabel Bennett
- London Centre for Nanotechnology, University College London, London, UK
| | - Edward S Parsons
- London Centre for Nanotechnology, University College London, London, UK
| | | | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, UK
- Institute of Structural and Molecular Biology, University College London, London, UK
- Department of Physics and Astronomy, University College London, London, UK
| | - Alice L B Pyne
- London Centre for Nanotechnology, University College London, London, UK.
- Department of Materials Science and Engineering, University of Sheffield, Sheffield, UK.
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10
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Hammond K, Ryadnov MG, Hoogenboom BW. Atomic force microscopy to elucidate how peptides disrupt membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183447. [PMID: 32835656 DOI: 10.1016/j.bbamem.2020.183447] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/30/2020] [Accepted: 08/13/2020] [Indexed: 12/24/2022]
Abstract
Atomic force microscopy is an increasingly attractive tool to study how peptides disrupt membranes. Often performed on reconstituted lipid bilayers, it provides access to time and length scales that allow dynamic investigations with nanometre resolution. Over the last decade, AFM studies have enabled visualisation of membrane disruption mechanisms by antimicrobial or host defence peptides, including peptides that target malignant cells and biofilms. Moreover, the emergence of high-speed modalities of the technique broadens the scope of investigations to antimicrobial kinetics as well as the imaging of peptide action on live cells in real time. This review describes how methodological advances in AFM facilitate new insights into membrane disruption mechanisms.
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Affiliation(s)
- Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; Department of Physics, King's College London, Strand Lane, London WC2R 2LS, UK.
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
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11
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Sepehri A, PeBenito L, Pino-Angeles A, Lazaridis T. What Makes a Good Pore Former: A Study of Synthetic Melittin Derivatives. Biophys J 2020; 118:1901-1913. [PMID: 32183940 DOI: 10.1016/j.bpj.2020.02.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/25/2020] [Accepted: 02/12/2020] [Indexed: 12/15/2022] Open
Abstract
Pore formation by membrane-active peptides, naturally encountered in innate immunity and infection, could have important medical and technological applications. Recently, the well-studied lytic peptide melittin has formed the basis for the development of combinatorial libraries from which potent pore-forming peptides have been derived, optimized to work under different conditions. We investigate three such peptides, macrolittin70, which is most active at neutral pH; pHD15, which is active only at low pH; and MelP5_Δ6, which was rationally designed to be active at low pH but formed only small pores. There are three, six, and six acidic residues in macrolittin70, pHD15, and MelP5_Δ6, respectively. We perform multi-microsecond simulations in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) of hexamers of these peptides starting from transmembrane orientations at neutral pH (all residues at standard protonation), low pH (acidic residues and His protonated), and highly acidic environments in which C-termini are also protonated. Previous simulations of the parent peptides melittin and MelP5 in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) are repeated in POPC. We find that the most potent pore-forming peptides exhibit strong interpeptide interactions, including salt bridges, H-bonds, and polar interactions. Protonation of the C-terminus promotes helicity and pore size. The proximity of the peptides allows fewer lipid headgroups to line the pores than in previous simulations, making the pores intermediate between barrel stave and toroidal. Based on these structures and geometrical arguments, we attempt to rationalize the factors that under different conditions can increase or decrease pore stability and propose mutations that could be tested experimentally.
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Affiliation(s)
- Aliasghar Sepehri
- Department of Chemistry & Biochemistry, The City College of New York, New York, New York
| | - Leo PeBenito
- Department of Chemistry & Biochemistry, The City College of New York, New York, New York; Graduate Program in Chemistry, The Graduate Center, City University of New York, New York, New York
| | - Almudena Pino-Angeles
- Department of Chemistry & Biochemistry, The City College of New York, New York, New York
| | - Themis Lazaridis
- Department of Chemistry & Biochemistry, The City College of New York, New York, New York; Graduate Program in Chemistry, The Graduate Center, City University of New York, New York, New York.
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Kim SY, Pittman AE, Zapata-Mercado E, King GM, Wimley WC, Hristova K. Mechanism of Action of Peptides That Cause the pH-Triggered Macromolecular Poration of Lipid Bilayers. J Am Chem Soc 2019; 141:6706-6718. [DOI: 10.1021/jacs.9b01970] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Sarah Y. Kim
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | - Elmer Zapata-Mercado
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | | | - William C. Wimley
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, Louisiana 70112, United States
| | - Kalina Hristova
- Department of Materials Science and Engineering, Institute for NanoBioTechnology, and Program in Molecular Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Guha S, Ghimire J, Wu E, Wimley WC. Mechanistic Landscape of Membrane-Permeabilizing Peptides. Chem Rev 2019; 119:6040-6085. [PMID: 30624911 DOI: 10.1021/acs.chemrev.8b00520] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Membrane permeabilizing peptides (MPPs) are as ubiquitous as the lipid bilayer membranes they act upon. Produced by all forms of life, most membrane permeabilizing peptides are used offensively or defensively against the membranes of other organisms. Just as nature has found many uses for them, translational scientists have worked for decades to design or optimize membrane permeabilizing peptides for applications in the laboratory and in the clinic ranging from antibacterial and antiviral therapy and prophylaxis to anticancer therapeutics and drug delivery. Here, we review the field of membrane permeabilizing peptides. We discuss the diversity of their sources and structures, the systems and methods used to measure their activities, and the behaviors that are observed. We discuss the fact that "mechanism" is not a discrete or a static entity for an MPP but rather the result of a heterogeneous and dynamic ensemble of structural states that vary in response to many different experimental conditions. This has led to an almost complete lack of discrete three-dimensional active structures among the thousands of known MPPs and a lack of useful or predictive sequence-structure-function relationship rules. Ultimately, we discuss how it may be more useful to think of membrane permeabilizing peptides mechanisms as broad regions of a mechanistic landscape rather than discrete molecular processes.
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Affiliation(s)
- Shantanu Guha
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Jenisha Ghimire
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - Eric Wu
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
| | - William C Wimley
- Department of Biochemistry and Molecular Biology Tulane University School of Medicine , New Orleans , Louisiana 70112 , United States
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