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Gabrielle M, Rohacs T. TMEM120A/TACAN: A putative regulator of ion channels, mechanosensation, and lipid metabolism. Channels (Austin) 2023; 17:2237306. [PMID: 37523628 PMCID: PMC10392765 DOI: 10.1080/19336950.2023.2237306] [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: 12/22/2022] [Revised: 06/19/2023] [Accepted: 07/12/2023] [Indexed: 08/02/2023] Open
Abstract
TMEM120A (TACAN) is an enigmatic protein with several seemingly unconnected functions. It was proposed to be an ion channel involved in sensing mechanical stimuli, and knockdown/knockout experiments have implicated that TMEM120A may be necessary for sensing mechanical pain. TMEM120A's ion channel function has subsequently been challenged, as attempts to replicate electrophysiological experiments have largely been unsuccessful. Several cryo-EM structures revealed TMEM120A is structurally homologous to a lipid modifying enzyme called Elongation of Very Long Chain Fatty Acids 7 (ELOVL7). Although TMEM120A's channel function is debated, it still seems to affect mechanosensation by inhibiting PIEZO2 channels and by modifying tactile pain responses in animal models. TMEM120A was also shown to inhibit polycystin-2 (PKD2) channels through direct physical interaction. Additionally, TMEM120A has been implicated in adipocyte regulation and in innate immune response against Zika virus. The way TMEM120A is proposed to alter each of these processes ranges from regulating gene expression, acting as a lipid modifying enzyme, and controlling subcellular localization of other proteins through direct binding. Here, we examine TMEM120A's structure and proposed functions in diverse physiological contexts.
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Affiliation(s)
- Matthew Gabrielle
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ, USA
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, Newark, NJ, USA
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2
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Wickline SA, Hou KK, Pan H. Peptide-Based Nanoparticles for Systemic Extrahepatic Delivery of Therapeutic Nucleotides. Int J Mol Sci 2023; 24:ijms24119455. [PMID: 37298407 DOI: 10.3390/ijms24119455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023] Open
Abstract
Peptide-based nanoparticles (PBN) for nucleotide complexation and targeting of extrahepatic diseases are gaining recognition as potent pharmaceutical vehicles for fine-tuned control of protein production (up- and/or down-regulation) and for gene delivery. Herein, we review the principles and mechanisms underpinning self-assembled formation of PBN, cellular uptake, endosomal release, and delivery to extrahepatic disease sites after systemic administration. Selected examples of PBN that have demonstrated recent proof of concept in disease models in vivo are summarized to offer the reader a comparative view of the field and the possibilities for clinical application.
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Affiliation(s)
- Samuel A Wickline
- Division of Cardiology, Department of Medical Engineering, University of South Florida, Tampa, FL 33602, USA
| | - Kirk K Hou
- Department of Ophthalmology, Stein and Doheny Eye Institutes, University of California, Los Angeles, CA 90095, USA
| | - Hua Pan
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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3
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Jemmett PN, Milan DC, Nichols RJ, Cox LR, Horswell SL. Effect of Molecular Structure on Electrochemical Phase Behavior of Phospholipid Bilayers on Au(111). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11887-11899. [PMID: 34590852 DOI: 10.1021/acs.langmuir.1c01975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Lipid bilayers form the basis of biological cell membranes, selective and responsive barriers vital to the function of the cell. The structure and function of the bilayer are controlled by interactions between the constituent molecules and so vary with the composition of the membrane. These interactions also influence how a membrane behaves in the presence of electric fields they frequently experience in nature. In this study, we characterize the electrochemical phase behavior of dipalmitoylphosphatidylcholine (DPPC), a glycerophospholipid prevalent in nature and often used in model systems and healthcare applications. DPPC bilayers were formed on Au(111) electrodes using Langmuir-Blodgett and Langmuir-Schaefer deposition and studied with electrochemical methods, atomic force microscopy (AFM) and in situ polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). The coverage of the substrate determined with AFM is in accord with that estimated from differential capacitance measurements, and the bilayer thickness is slightly higher than for bilayers of the similar but shorter-chained lipid, dimyristoylphosphatidylcholine (DMPC). DPPC bilayers exhibit similar electrochemical response to DMPC bilayers, but the organization of molecules differs, particularly at negative charge densities. Infrared spectra show that DPPC chains tilt as the charge density on the metal is increased in the negative direction, but, unlike in DMPC, the chains then return to their original tilt angle at the most negative potentials. The onset of the increase in the chain tilt angle coincides with a decrease in solvation around the ester carbonyl groups, and the conformation around the acyl chain linkage differs from that in DMPC. We interpret the differences in behavior between bilayers formed from these structurally similar lipids in terms of stronger dispersion forces between DPPC chains and conclude that relatively subtle changes in molecular structure may have a significant impact on a membrane's response to its environment.
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Affiliation(s)
- Philip N Jemmett
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - David C Milan
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Richard J Nichols
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Liam R Cox
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Sarah L Horswell
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
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4
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Swana KW, Nagarajan R, Camesano TA. Atomic Force Microscopy to Characterize Antimicrobial Peptide-Induced Defects in Model Supported Lipid Bilayers. Microorganisms 2021; 9:microorganisms9091975. [PMID: 34576869 PMCID: PMC8465339 DOI: 10.3390/microorganisms9091975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/07/2021] [Accepted: 09/13/2021] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial peptides (AMPs) interact with bacterial cell membranes through a variety of mechanisms, causing changes extending from nanopore formation to microscale membrane lysis, eventually leading to cell death. Several AMPs also disrupt mammalian cell membranes, despite their significantly different lipid composition and such collateral hemolytic damage hinders the potential therapeutic applicability of the AMP as an anti-microbial. Elucidating the mechanisms underlying the AMP-membrane interactions is challenging due to the variations in the chemical and structural features of the AMPs, the complex compositional variations of cell membranes and the inadequacy of any single experimental technique to comprehensively probe them. (1) Background: Atomic Force Microscopy (AFM) imaging can be used in combination with other techniques to help understand how AMPs alter the orientation and structural organization of the molecules within cell membranes exposed to AMPs. The structure, size, net charge, hydrophobicity and amphipathicity of the AMPs affect how they interact with cell membranes of differing lipid compositions. (2) Methods: Our study examined two different types of AMPs, a 20-amino acid, neutral, α-helical (amphipathic) peptide, alamethicin, and a 13-amino acid, non-α-helical cationic peptide, indolicidin (which intramolecularly folds, creating a hydrophobic core), for their interactions with supported lipid bilayers (SLBs). Robust SLB model membranes on quartz supports, incorporating predominantly anionic lipids representative of bacterial cells, are currently not available and remain to be developed. Therefore, the SLBs of zwitterionic egg phosphatidylcholine (PC), which represents the composition of a mammalian cell membrane, was utilized as the model membrane. This also allows for a comparison with the results obtained from the Quartz Crystal Microbalance with Dissipation (QCM-D) experiments conducted for these peptides interacting with the same zwitterionic SLBs. Further, in the case of alamethicin, because of its neutrality, the lipid charge may be less relevant for understanding its membrane interactions. (3) Results: Using AFM imaging and roughness analysis, we found that alamethicin produced large, unstable defects in the membrane at 5 µM concentrations, and completely removed the bilayer at 10 µM. Indolicidin produced smaller holes in the bilayer at 5 and 10 µM, although they were able to fill in over time. The root-mean-square (RMS) roughness values for the images showed that the surface roughness caused by visible defects peaked after peptide injection and gradually decreased over time. (4) Conclusions: AFM is useful for helping to uncover the dynamic interactions between different AMPs and cell membranes, which can facilitate the selection and design of more efficient AMPs for use in therapeutics and antimicrobial applications.
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Affiliation(s)
- Kathleen W. Swana
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA;
- U.S. Army Combat Capabilities Development Command Soldier Center, Natick, MA 01760, USA;
| | - Ramanathan Nagarajan
- U.S. Army Combat Capabilities Development Command Soldier Center, Natick, MA 01760, USA;
| | - Terri A. Camesano
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA;
- Correspondence:
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5
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Bertrand B, Garduño-Juárez R, Munoz-Garay C. Estimation of pore dimensions in lipid membranes induced by peptides and other biomolecules: A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183551. [PMID: 33465367 DOI: 10.1016/j.bbamem.2021.183551] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 02/07/2023]
Abstract
The cytoplasmic membrane is one of the most frequent cell targets of antimicrobial peptides (AMPs) and other biomolecules. Understanding the mechanism of action of AMPs at the molecular level is of utmost importance for designing of new membrane-specific molecules. In particular, the formation of pores, the structure and size of these pores are of great interest and require nanoscale resolution approaches, therefore, biophysical strategies are essential to achieve an understanding of these processes at this scale. In the case of membrane active peptides, pore formation or general membrane disruption is usually the last step before cell death, and so, pore size is generally directly associated to pore structure and stability and loss of cellular homeostasis, implicated in overall peptide activity. Up to date, there has not been a critical review discussing the methods that can be used specifically for estimating the pore dimensions induced by membrane active peptides. In this review we discuss the scope, relevance and popularity of the different biophysical techniques such as liposome leakage experiments, advanced microscopy, neutron or X-ray scattering, electrophysiological techniques and molecular dynamics studies, all of them useful for determining pore structure and dimension.
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Affiliation(s)
- Brandt Bertrand
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Avenida Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, Mexico
| | - Ramón Garduño-Juárez
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Avenida Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, Mexico
| | - Carlos Munoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México (ICF-UNAM), Avenida Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, Mexico.
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6
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Coker HLE, Cheetham MR, Kattnig DR, Wang YJ, Garcia-Manyes S, Wallace MI. Controlling Anomalous Diffusion in Lipid Membranes. Biophys J 2019; 116:1085-1094. [PMID: 30846364 DOI: 10.1016/j.bpj.2018.12.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 11/21/2018] [Accepted: 12/14/2018] [Indexed: 12/24/2022] Open
Abstract
Diffusion in cell membranes is not just simple two-dimensional Brownian motion but typically depends on the timescale of the observation. The physical origins of this anomalous subdiffusion are unresolved, and model systems capable of quantitative and reproducible control of membrane diffusion have been recognized as a key experimental bottleneck. Here, we control anomalous diffusion using supported lipid bilayers containing lipids derivatized with polyethylene glycol (PEG) headgroups. Bilayers with specific excluded area fractions are formed by control of PEG lipid mole fraction. These bilayers exhibit a switch in diffusive behavior, becoming anomalous as bilayer continuity is disrupted. Using a combination of single-molecule fluorescence and interferometric imaging, we measure the anomalous behavior in this model over four orders of magnitude in time. Diffusion in these bilayers is well described by a power-law dependence of the mean-square displacement with observation time. Anomaleity in this system can be tailored by simply controlling the mole fraction of PEG lipid, producing bilayers with diffusion parameters similar to those observed for anomalous diffusion in biological membranes.
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Affiliation(s)
- Helena L E Coker
- Department of Chemistry, King's College London, London, United Kingdom; Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Matthew R Cheetham
- Department of Chemistry, King's College London, London, United Kingdom; Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Daniel R Kattnig
- Living Systems Institute & Department of Physics, University of Exeter, Exeter, United Kingdom
| | - Yong J Wang
- Department of Physics, King's College London, London, United Kingdom
| | | | - Mark I Wallace
- Department of Chemistry, King's College London, London, United Kingdom.
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7
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Du L, Risinger AL, Mitchell CA, You J, Stamps BW, Pan N, King JB, Bopassa JC, Judge SIV, Yang Z, Stevenson BS, Cichewicz RH. Unique amalgamation of primary and secondary structural elements transform peptaibols into potent bioactive cell-penetrating peptides. Proc Natl Acad Sci U S A 2017; 114:E8957-E8966. [PMID: 29073092 PMCID: PMC5664515 DOI: 10.1073/pnas.1707565114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Mass-spectrometry-based metabolomics and molecular phylogeny data were used to identify a metabolically prolific strain of Tolypocladium that was obtained from a deep-water Great Lakes sediment sample. An investigation of the isolate's secondary metabolome resulted in the purification of a 22-mer peptaibol, gichigamin A (1). This peptidic natural product exhibited an amino acid sequence including several β-alanines that occurred in a repeating ααβ motif, causing the compound to adopt a unique right-handed 311 helical structure. The unusual secondary structure of 1 was confirmed by spectroscopic approaches including solution NMR, electronic circular dichroism (ECD), and single-crystal X-ray diffraction analyses. Artificial and cell-based membrane permeability assays provided evidence that the unusual combination of structural features in gichigamins conferred on them an ability to penetrate the outer membranes of mammalian cells. Compound 1 exhibited potent in vitro cytotoxicity (GI50 0.55 ± 0.04 µM) and in vivo antitumor effects in a MIA PaCa-2 xenograft mouse model. While the primary mechanism of cytotoxicity for 1 was consistent with ion leakage, we found that it was also able to directly depolarize mitochondria. Semisynthetic modification of 1 provided several analogs, including a C-terminus-linked coumarin derivative (22) that exhibited appreciably increased potency (GI50 5.4 ± 0.1 nM), but lacked ion leakage capabilities associated with a majority of naturally occurring peptaibols such as alamethicin. Compound 22 was found to enter intact cells and induced cell death in a process that was preceded by mitochondrial depolarization.
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Affiliation(s)
- Lin Du
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
- Natural Products Discovery Group, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK 73019-5251
| | - April L Risinger
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229
- Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio, TX 78229
| | - Carter A Mitchell
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
- Natural Products Discovery Group, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK 73019-5251
| | - Jianlan You
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
- Natural Products Discovery Group, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK 73019-5251
| | - Blake W Stamps
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019-5251
| | - Ning Pan
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
| | - Jarrod B King
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
- Natural Products Discovery Group, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK 73019-5251
| | - Jean C Bopassa
- Department of Physiology, School of Medicine, University of Texas Health Science Center, San Antonio, TX 78229
| | - Susan I V Judge
- Department of Biochemistry, High Throughput Screening Facility, Center for Innovative Drug Discovery, University of Texas Health Science Center, San Antonio, TX 78229
- CytoBioscience Incorporated, San Antonio, TX 78229
| | - Zhibo Yang
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
| | - Bradley S Stevenson
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019-5251
| | - Robert H Cichewicz
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, OK 73019-5251;
- Natural Products Discovery Group, Institute for Natural Products Applications and Research Technologies, University of Oklahoma, Norman, OK 73019-5251
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8
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Bodescu MA, Rosenkötter F, Fritz J. Time lapse AFM on vesicle formation from mixed lipid bilayers induced by the membrane-active peptide melittin. SOFT MATTER 2017; 13:6845-6851. [PMID: 28829104 DOI: 10.1039/c7sm01095h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Melittin is a model system for the action of antimicrobial peptides which are potential candidates for novel antibiotics. We investigated the membrane lysis effect of melittin on phase-separated supported lipid bilayers (DOPC-DPPC) by atomic force microscopy. AFM images show that the peptide first forms defects at the interface between the two lipid phases and then degrades preferentially the liquid-phase DOPC-enriched domains. Vesicular structures of 10-20 nm radius were observed to form, suggesting a mixed carpet-toroidal model mechanism for the resolved action of melittin.
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Affiliation(s)
- M A Bodescu
- Jacobs University Bremen, Department of Physics & Earth Sciences, Campus Ring 1, 28759 Bremen, Germany.
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9
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Himbert S, Chapman M, Deamer DW, Rheinstädter MC. Organization of Nucleotides in Different Environments and the Formation of Pre-Polymers. Sci Rep 2016; 6:31285. [PMID: 27545761 PMCID: PMC4992878 DOI: 10.1038/srep31285] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 07/15/2016] [Indexed: 11/19/2022] Open
Abstract
RNA is a linear polymer of nucleotides linked by a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. However, in the absence of enzymes and metabolism there has been no obvious way for RNA-like molecules to be produced and then encapsulated in cellular compartments. We investigated 5′-adenosine monophosphate (AMP) and 5′-uridine monophosphate (UMP) molecules confined in multi-lamellar phospholipid bilayers, nanoscopic films, ammonium chloride salt crystals and Montmorillonite clay, previously proposed to promote polymerization. X-ray diffraction was used to determine whether such conditions imposed a degree of order on the nucleotides. Two nucleotide signals were observed in all matrices, one corresponding to a nearest neighbour distance of 4.6 Å attributed to nucleotides that form a disordered, glassy structure. A second, smaller distance of 3.4 Å agrees well with the distance between stacked base pairs in the RNA backbone, and was assigned to the formation of pre-polymers, i.e., the organization of nucleotides into stacks of about 10 monomers. Such ordering can provide conditions that promote the nonenzymatic polymerization of RNA strands under prebiotic conditions. Experiments were modeled by Monte-Carlo simulations, which provide details of the molecular structure of these pre-polymers.
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Affiliation(s)
- Sebastian Himbert
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4M1, Canada.,Origins Institute, McMaster University, Hamilton, L8S 4M1, Canada.,Department of Experimental Physics, Saarland University, 66123 Saarbrücken, Germany
| | - Mindy Chapman
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4M1, Canada.,Origins Institute, McMaster University, Hamilton, L8S 4M1, Canada
| | - David W Deamer
- Department of Biomolecular Engineering, University of California, Santa Cruz, 95064, USA
| | - Maikel C Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, L8S 4M1, Canada.,Origins Institute, McMaster University, Hamilton, L8S 4M1, Canada
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10
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Pan J, Khadka NK. Kinetic Defects Induced by Melittin in Model Lipid Membranes: A Solution Atomic Force Microscopy Study. J Phys Chem B 2016; 120:4625-34. [PMID: 27167473 DOI: 10.1021/acs.jpcb.6b02332] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Quantitative characterization of membrane defects (pores) is important for elucidating the molecular basis of many membrane-active peptides. We study kinetic defects induced by melittin in vesicular and planar lipid bilayers. Fluorescence spectroscopy measurements indicate that melittin induces time-dependent calcein leakage. Solution atomic force microscopy (AFM) is used to visualize melittin-induced membrane defects. After initial equilibration, the most probable defect radius is ∼3.8 nm in 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) bilayers. Unexpectedly, defects become larger with longer incubation, accompanied by substantial shape transformation. The initial defect radius is ∼4.7 nm in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers. Addition of 30 mol % cholesterol to DOPC bilayers suppresses defect kinetics, although the inhibitory impact is negated by longer incubation. Overall, the kinetic rate of defect development follows DLPC > DOPC > DOPC/cholesterol. Kinetic defects are also observed when anionic lipids are present. Based on the observation that defects can occupy as large as 40% of the bilayer surface, we propose a kinetic defect growth model. We also study the effect of melittin on the phase behavior of DOPC/egg-sphingomyelin/cholesterol bilayers. We find that melittin initially suppresses or eliminates liquid-ordered (Lo) domains; Lo domains gradually emerge and become the dominant species with longer incubation; and defects in phase-coexisting bilayers have a most probable radius of ∼5 nm and are exclusively localized in the liquid-disordered (Ld) phase. Our experimental data highlight that melittin-induced membrane defects are not static; conversely, spontaneous defect growth is intrinsically associated with membrane permeabilization exerted by melittin.
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Affiliation(s)
- Jianjun Pan
- Department of Physics, University of South Florida , Tampa, Florida 33620, United States
| | - Nawal K Khadka
- Department of Physics, University of South Florida , Tampa, Florida 33620, United States
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11
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Vertical ordering sensitivity of solid supported DPPC membrane to alamethicin and the related loss of cell viability. Biochim Biophys Acta Gen Subj 2015; 1850:759-68. [PMID: 25597953 DOI: 10.1016/j.bbagen.2015.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 12/23/2014] [Accepted: 01/08/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND Experimental studies of antimicrobial peptides interacting with lipid membranes recently attracted growing interest due to their numerous biomedical applications. However, the influence of such peptides on the structural organisation of lipid membranes in connection with the actual cell response still remains an elusive issue. METHODS X-ray diffraction was employed on detecting the sensitivity of the periodical spacing of dipalmitoyl-phosphatidyl-choline stacked as solid-supported bilayers to the presence of varying amounts of the peptide alamethicin in a wide range of peptide-to-lipid molar ratios. These results were then correlated with the effects of alamethicin on biological membranes in vitro as observed by optical microscopy and microculture tetrazolium assay on the tumour cells HeLa to provide a comprehensive and quantitative analysis of these effects, based on a dose-response relationship. RESULTS The experiments allowed correlating the periodical spacing and the peptide-to-lipid molar ratio on alamethicin-dipalmitoyl-phosphatidyl-choline samples. Two different trends of periodical spacing vs. peptide-to-lipid molar ratio clearly appeared at low and high hydration levels, showing intriguing non-linear profiles. Unexpected correspondences were observed between the peptide-to-lipid molar ratio range where the changes in dipalmitoyl-phosphatidyl-choline structure occur and the alamethicin doses which alter the viability and the plasma membrane morphology of HeLa. CONCLUSIONS Alamethicin might induce either mechanical or phase changes on dipalmitoyl-phosphatidyl-choline bilayers. Such easily accessible ordering information was well-calibrated to predict the alamethicin doses necessary to trigger cell death through plasma membrane alterations. GENERAL SIGNIFICANCE This benchmark combined study may be valuable to predict bioeffects of several antimicrobial peptides of biomedical relevance.
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12
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Lind TK, Zielińska P, Wacklin HP, Urbańczyk-Lipkowska Z, Cárdenas M. Continuous flow atomic force microscopy imaging reveals fluidity and time-dependent interactions of antimicrobial dendrimer with model lipid membranes. ACS NANO 2014; 8:396-408. [PMID: 24303991 DOI: 10.1021/nn404530z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this paper, an amphiphilic peptide dendrimer with potential applications against multi-resistant bacteria such as Staphylococcus aureus was synthesized and studied on model cell membranes. The combination of quartz crystal microbalance and atomic force microscopy imaging during continuous flow allowed for in situ monitoring of the very initial interaction processes and membrane transformations on longer time scales. We used three different membrane compositions of low and high melting temperature phospholipids to vary the membrane properties from a single fluid phase to a pure gel phase, while crossing the phase coexistence boundaries at room temperature. The interaction mechanism of the dendrimer was found to be time-dependent and to vary remarkably with the fluidity and coexistence of liquid-solid phases in the membrane. Spherical micelle-like dendrimer-lipid aggregates were formed in the fluid-phase bilayer and led to partial solubilization of the membrane, while in gel-phase membranes, the dendrimers caused areas of local depressions followed by redeposition of flexible lipid patches. Domain coexistence led to a sequence of events initiated by the formation of a ribbon-like network and followed by membrane solubilization via spherical aggregates from the edges of bilayer patches. Our results show that the dendrimer molecules were able to destroy the membrane integrity through different mechanisms depending on the lipid phase and morphology and shed light on their antimicrobial activity. These findings could have an impact on the efficacy of the dendrimers since lipid membranes in certain bacteria have transition temperatures very close to the host body temperature.
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Affiliation(s)
- Tania Kjellerup Lind
- Nano-Science Center and Institute of Chemistry, Copenhagen University , København DK2100, Denmark
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13
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Ratoi M, Hoet PHM, Crossley A, Dobson P. Impact of lung surfactant on wettability and cytotoxicity of nanoparticles. RSC Adv 2014. [DOI: 10.1039/c3ra47374k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The establishment of relevant nanoparticle characterization parameters and testing strategies, which facilitate the replication of the lung surfactantin vivoaction, are essential to reaching consensus in nanotoxicity research results.
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Affiliation(s)
- Monica Ratoi
- Faculty of Engineering and Environment
- University of Southampton
- Southampton SO17 1BJ, UK
| | - Peter H. M. Hoet
- Laboratory of Pneumology
- Unit for Lung Toxicity
- K. U. Leuven
- 3000 Leuven, Belgium
| | | | - Peter Dobson
- Begbroke Science Park Directorate
- University of Oxford
- UK OX5 1PF
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Kredics L, Szekeres A, Czifra D, Vágvölgyi C, Leitgeb B. Recent results in alamethicin research. Chem Biodivers 2013; 10:744-71. [PMID: 23681724 DOI: 10.1002/cbdv.201200390] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Indexed: 12/20/2022]
Affiliation(s)
- László Kredics
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, H-6726 Szeged.
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15
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Oliynyk V, Mille C, Ng JBS, von Ballmoos C, Corkery RW, Bergström L. Selective and ATP-driven transport of ions across supported membranes into nanoporous carriers using gramicidin A and ATP synthase. Phys Chem Chem Phys 2013; 15:2733-40. [PMID: 23321853 DOI: 10.1039/c2cp43166a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a robust and versatile membrane protein based system for selective uptake and release of ions from nanoporous particles sealed with ion-tight lipid bilayers of various compositions that is driven by the addition of ATP or a chemical potential gradient. We have successfully incorporated both a passive ion channel-type peptide (gramicidin A) and a more complex primary sodium ion transporter (ATP synthase) into the supported lipid bilayers on solid nanoporous silica particles. Protein-mediated controlled release/uptake of sodium ions across the ion-tight lipid bilayer seal from or into the nanoporous silica carrier was imaged in real time using a confocal laser scanning microscope and the intensity changes were quantified. ATP-driven transport of sodium ions across the supported lipid bilayer against a chemical gradient was demonstrated. The possibility of designing durable carriers with tight lipid membranes, containing membrane proteins for selective ion uptake and release, offers new possibilities for functional studies of single or cascading membrane protein systems and could also be used as biomimetic microreactors for controlled synthesis of inorganic multicomponent materials.
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Affiliation(s)
- Vitaliy Oliynyk
- Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm, Sweden
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16
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Toppozini L, Dies H, Deamer DW, Rheinstädter MC. Adenosine monophosphate forms ordered arrays in multilamellar lipid matrices: insights into assembly of nucleic acid for primitive life. PLoS One 2013; 8:e62810. [PMID: 23667523 PMCID: PMC3646914 DOI: 10.1371/journal.pone.0062810] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/26/2013] [Indexed: 11/18/2022] Open
Abstract
A fundamental question of biology is how nucleic acids first assembled and then were incorporated into the earliest forms of cellular life 4 billion years ago. The polymerization of nucleotides is a condensation reaction in which phosphodiester bonds are formed. This reaction cannot occur in aqueous solutions, but guided polymerization in an anhydrous lipid environment could promote a non-enzymatic condensation reaction in which oligomers of single stranded nucleic acids are synthesized. We used X-ray scattering to investigate 5′-adenosine monophosphate (AMP) molecules captured in a multilamellar phospholipid matrix composed of dimyristoylphosphatidylcholine. Bragg peaks corresponding to the lateral organization of the confined AMP molecules were observed. Instead of forming a random array, the AMP molecules are highly entangled, with the phosphate and ribose groups in close proximity. This structure may facilitate polymerization of the nucleotides into RNA-like polymers.
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Affiliation(s)
- Laura Toppozini
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- Origins Institute, McMaster University, Hamilton, Ontario, Canada
- * E-mail: (LT); (DWD); (MCR))
| | - Hannah Dies
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - David W. Deamer
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
- * E-mail: (LT); (DWD); (MCR))
| | - Maikel C. Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- Origins Institute, McMaster University, Hamilton, Ontario, Canada
- Canadian Neutron Beam Centre, National Research Council Canada, Chalk River Laboratories, Chalk River, Ontario, Canada
- * E-mail: (LT); (DWD); (MCR))
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17
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Essone Mezeme M, Brosseau C. Engineering nanostructures with enhanced thermoplasmonic properties for biosensing and selective targeting applications. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:012722. [PMID: 23410374 DOI: 10.1103/physreve.87.012722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/04/2012] [Indexed: 06/01/2023]
Abstract
This paper connects the study of thermoplasmonic properties in nanoscale particles with areas of biophysics involving a cell membrane with or without conductive pores. Using a quasistatic finite element modeling of the heat transfer equation in three dimensions we simulate the stationary heat generation and temperature field around several types of gold-based nanostructures. Models were constructed that emphasized the importance of obtaining precise temperature fields that might subsequently be used for biosensing and selective targeting applications. By analyzing the observed temperature increase, effective complex permittivity, and electric field enhancement that result from plasmonic resonance, this theoretical framework provides insight into the role of the nanoparticle shape in heat generation. To illustrate the usefulness of this approach for biosensing applications, we consider how the positioning of the nanoantenna affects heating efficiency. Linear response calculations of the temperature increase reveal that symmetric gold nanosphere dimers are not only suitable for sensing applications, but can also play the role of heat sources which are more efficient than the case of a single nanosphere. We also predict that this specific type of nanoantenna allows us to detect the presence and size of a hole in the cell membrane. These results provide insight into the physics of the cell membrane and provide guidance for more detailed studies of the nanoscale control of temperature in biological materials.
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Affiliation(s)
- M Essone Mezeme
- Université Européenne de Bretagne, Université de Brest, Lab-STICC, CS 93837, 6 avenue Le Gorgeu, 29238 Brest Cedex 3, France
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18
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Toppozini L, Armstrong CL, Kaye MD, Tyagi M, Jenkins T, Rheinstädter MC. Hydration Water Freezing in Single Supported Lipid Bilayers. ACTA ACUST UNITED AC 2012. [DOI: 10.5402/2012/520307] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We present a high-temperature and high-energy resolution neutron scattering investigation of hydration water freezing in single supported lipid bilayers. Single supported lipid bilayers provide a well-defined biological interface to study hydration water dynamics and coupling to membrane degrees of freedom. Nanosecond molecular motions of membrane and hydration water were studied in the temperature range 240 K < T < 290 K in slow heating and cooling cycles using coherent and incoherent elastic neutron scattering on a backscattering spectrometer. Several freezing and melting transitions were observed. From the length scale dependence of the elastic scattering, these transitions could be assigned to freezing and melting of hydration water dynamics, diffusive lipid, and lipid acyl-tail dynamics. Coupling was investigated by comparing the different freezing and melting temperatures. While it is often speculated that membrane and hydration water dynamics are strongly coupled, we find that membrane and hydration water dynamics are at least partially decoupled in single bilayers.
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Affiliation(s)
- Laura Toppozini
- Department of Physics & Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1
| | - Clare L. Armstrong
- Department of Physics & Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1
| | - Martin D. Kaye
- Department of Physics & Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1
| | - Madhusudan Tyagi
- NIST Center for Neutron Research, NIST, Gaithersburg, MD 20899, USA
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Timothy Jenkins
- NIST Center for Neutron Research, NIST, Gaithersburg, MD 20899, USA
| | - Maikel C. Rheinstädter
- Department of Physics & Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1
- Canadian Neutron Beam Centre, National Research Council Canada, Chalk River, ON, Canada K0J 1J0
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19
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Bishop CM, Wimley WC. Structural plasticity in self-assembling transmembrane β-sheets. Biophys J 2011; 101:828-36. [PMID: 21843473 DOI: 10.1016/j.bpj.2011.06.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 06/23/2011] [Accepted: 06/28/2011] [Indexed: 10/17/2022] Open
Abstract
Here we test the hypothesis that membrane-spanning β-sheets can exhibit structural plasticity in membranes due to their ability to shift hydrogen-bonding patterns. Transmembrane β-sheet forming peptides of the sequence AcWL(n), where n = 5, 6, or 7, which range from 21 to 27 Å in maximum length, were incorporated into bilayers made of phosphatidylcholine lipids with saturated acyl chains containing 14, 16, or 18 carbons, which are 36-50 Å in thickness. The effect of the peptide β-sheets on fluid- and gel-phase bilayers were studied with differential scanning calorimetry and circular dichroism spectroscopy. We show that AcWL₅ forms a stable, peptide-rich gel phase in all three lipids. The whole family of AcWL(n) peptides appears to form similarly stable, nonmembrane-disrupting β-sheets in all bilayer phases and thicknesses. Bilayers containing up to 20 mol % peptide, which is the maximum concentration tested, formed gel phases with melting temperatures that were equal to, or slightly higher than, the pure lipid transitions. Given the range of peptide lengths and bilayer thicknesses tested, these experiments show that the AcWL(n) family of membrane-inserted β-sheets exhibit remarkable structural plasticity in membranes.
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Affiliation(s)
- Christopher M Bishop
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana, USA
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20
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Heimburg T. Lipid ion channels. Biophys Chem 2010; 150:2-22. [DOI: 10.1016/j.bpc.2010.02.018] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 02/27/2010] [Accepted: 02/27/2010] [Indexed: 10/19/2022]
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21
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Macháň R, Miszta A, Hermens W, Hof M. Real-time monitoring of melittin-induced pore and tubule formation from supported lipid bilayers and its physiological relevance. Chem Phys Lipids 2010; 163:200-6. [DOI: 10.1016/j.chemphyslip.2009.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 10/12/2009] [Accepted: 11/12/2009] [Indexed: 11/30/2022]
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22
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Phospholipid flip-flop modulated by transmembrane peptides WALP and melittin. J Struct Biol 2009; 168:37-52. [PMID: 19508895 DOI: 10.1016/j.jsb.2009.06.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Revised: 05/29/2009] [Accepted: 06/02/2009] [Indexed: 11/21/2022]
Abstract
Select transmembrane proteins found in biogenic membranes are known to facilitate rapid bidirectional flip-flop of lipids between the membrane leaflets, while others have no little or no effect. The particular characteristics which determine the extent to which a protein will facilitate flip-flop are still unknown. To determine if the relative polarity of the transmembrane protein segment influences its capacity for facilitation of flip-flop, we have studied lipid flip-flop dynamics for bilayers containing the peptides WALP(23) and melittin. WALP(23) is used as a model hydrophobic peptide, while melittin consists of both hydrophobic and hydrophilic residues. Sum-frequency vibrational spectroscopy (SFVS) was used to characterize the bilayers and determine the kinetics of flip-flop for the lipid component, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), within the mixed bilayers. The kinetic data were utilized to determine the activation thermodynamics for DSPC flip-flop in the presence of the peptides. Melittin was found to significantly reduce the free energy barrier to DSPC flip-flop when incorporated into the bilayer at 1mol.%, while incorporation of WALP(23) at the same concentration led to a more modest reduction of the free energy barrier. The possible mechanisms by which these peptides facilitate flip-flop are analyzed and discussed in terms of the observed activation thermodynamics.
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23
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Salnikov ES, Zotti MD, Formaggio F, Li X, Toniolo C, OʼNeil JDJ, Raap J, Dzuba SA, Bechinger B. Alamethicin Topology in Phospholipid Membranes by Oriented Solid-state NMR and EPR Spectroscopies: a Comparison. J Phys Chem B 2009; 113:3034-42. [DOI: 10.1021/jp8101805] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Evgeniy S. Salnikov
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Marta De Zotti
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Fernando Formaggio
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Xing Li
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Claudio Toniolo
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Joe D. J. OʼNeil
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Jan Raap
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Sergei A. Dzuba
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
| | - Burkhard Bechinger
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation, University of Strasbourg/CNRS, UMR7177, Institut de Chimie, 67070 Strasbourg, France, Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131 Padova, Italy, Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2, and Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 RA Leiden, The Netherlands
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24
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Oliynyk V, Jäger M, Heimburg T, Buckin V, Kaatze U. Lipid membrane domain formation and alamethicin aggregation studied by calorimetry, sound velocity measurements, and atomic force microscopy. Biophys Chem 2008; 134:168-77. [DOI: 10.1016/j.bpc.2008.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 02/07/2008] [Accepted: 02/09/2008] [Indexed: 11/29/2022]
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