The Single GUV Method for Probing Biomembrane Structure and Function

Yamazaki, Masahito; Tamba, Yukihiro

doi:10.1380/ejssnt.2005.218

Cited by 16 publications

(16 citation statements)

References 25 publications

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“…In those studies, the average values of the physical parameters of liposomes were obtained from a large number of liposomes, and thereby much information was lost. We have proposed a novel method, the single GUV method, to probe functions and dynamics of biomembranes (21,27). In the single GUV method, we observe structures and physical properties of single GUVs as a function of time and spatial coordinates and make statistical analysis of the physical properties of a single GUV over many single GUVs.…”

Section: Advantage Of the Single Guv Methodsmentioning

confidence: 99%

“…In those studies, the average values of the physical parameters of liposomes were obtained from a large number of liposomes, and thereby much information was lost. In contrast, studies of single GUVs provide information on the structure and physical properties of single GUVs as a function of time and spatial coordinates, and the statistical analysis of the physical properties of many single GUVs can provide a great deal of new information on the structure and function of biomembranes and lipid membranes which cannot be obtained from studies using suspensions of LUVs and SUVs (the single GUV method) (21). For example, the single GUV method has been successfully used to study membrane fusion and vesicle fission (22,23).…”

Section: Introductionmentioning

confidence: 99%

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Single GUV Method Reveals Interaction of Tea Catechin (−)-Epigallocatechin Gallate with Lipid Membranes

Tamba

Ohba

Kubota

et al. 2007

Biophysical Journal

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138

178

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Tea catechins, which are flavonoids and the main components of green tea extracts, are thought to have antibacterial and antioxidant activity. Several studies indicate that lipid membranes are one of the targets of the antibacterial activity of catechins. Studies using a suspension of large unilamellar vesicles (LUVs) indicate that catechin causes gradual leakage of internal contents from LUVs. However, the detailed characteristics of the interaction of catechins with lipid membranes remain unclear. In this study, we investigated the interaction of (-)-epigallocatechin gallate (EGCg), a major catechin in tea extract, with single giant unilamellar vesicles (GUVs) of egg phosphatidylcholine (egg PC) using phase-contrast fluorescence microscopy and the single GUV method. We prepared GUVs of lipid membranes of egg PC in a physiological ion concentration ( approximately 150 mM NaCl) using the polyethylene glycol-lipid method. Low concentrations of EGCg at and above 30 muM induced rapid leakage of a fluorescent probe, calcein, from the inside of single egg PC-GUVs; after the leakage, the GUVs changed into small lumps of lipid membranes. On the other hand, phase-contrast microscopic images revealed the detailed process of the EGCg-induced burst of GUVs, the decrease in their diameter, and their transformation into small lumps. The dependence of the fraction of burst GUVs on EGCg concentration was almost the same as that of the fraction of leaked GUV. This correlation strongly indicates that the leakage of calcein from the inside to the outside of the GUV occurred as a result of the burst of the GUV. The fraction of completely leaked GUV and the fraction of the burst GUV increased with time and also increased with increasing EGCg concentration. We compared the EGCg-induced leakage from single GUVs with EGCg-induced leakage from a LUV suspension. The analysis of the EGCg-induced shape changes shows that the binding of EGCg to the external monolayer of the GUV increases its membrane area, inducing an increase in its surface pressure. Small angle x-ray scattering experiments indicate that the intermembrane distance of multilamellar vesicles of PC membrane greatly decreased at EGCg concentrations above the threshold, suggesting that neighboring membranes came in close contact with each other. On the basis of these results, we discuss the mechanism of the EGCg-induced bursting of vesicles.

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Section: Advantage Of the Single Guv Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single GUV Method Reveals Interaction of Tea Catechin (−)-Epigallocatechin Gallate with Lipid Membranes

Tamba

Ohba

Kubota

et al. 2007

Biophysical Journal

Self Cite

138

178

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show abstract

“…Membrane fusion is a phenomenon that has physical, chemical, and biological aspects 3 – 5 . The energy barrier for the fusion process is the contact between two bilayer membranes and the formation of an intermediate hemi-fusion state.…”

Section: Introductionmentioning

confidence: 99%

Formation of Cell Membrane Component Domains in Artificial Lipid Bilayer

Tero

Fukumoto

Motegi

et al. 2017

Sci Rep

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The lipid bilayer environment around membrane proteins strongly affects their structure and functions. Here, we aimed to study the fusion of proteoliposomes (PLs) derived from cultured cells with an artificial lipid bilayer membrane and the distribution of the PL components after the fusion. PLs, which were extracted as a crude membrane fraction from Chinese hamster ovary (CHO) cells, formed isolated domains in a supported lipid bilayer (SLB), comprising phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cholesterol (Chol), after the fusion. Observation with a fluorescence microscope and an atomic force microscope showed that the membrane fusion occurred selectively at microdomains in the PC + PE + Chol-SLB, and that almost all the components of the PL were retained in the domain. PLs derived from human embryonic kidney 293 (HEK) cells also formed isolated domains in the PC + PE + Chol-SLB, but their fusion kinetics was different from that of the CHO-PLs. We attempted to explain the mechanism of the PL-SLB fusion and the difference between CHO- and HEK-PLs, based on a kinetic model. The domains that contained the whole cell membrane components provided environments similar to that of natural cell membranes, and were thus effective for studying membrane proteins using artificial lipid bilayer membranes.

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“…Giant unilamellar vesicles (GUVs) can be formed either by spontaneous formation (Akashi et al 1996) or by electroformation (Angelova and Dimitrov 1986), and have been extensively reviewed in the literature (Yamazaki and Tamba 2005;Dimova et al 2006;Riske 2015). Briefly, in spontaneous formation, after the solvent has been completely removed by vacuum, the lipid film, whether or not it contains fluorescently labeled lipid, is pre-hydrated with a very small volume of water (~10 μl) at 45°C for a short time,~10 min.…”

Section: Model Membranes and Strategies For Investigating Lipid-packimentioning

confidence: 99%

Lipid-packing perturbation of model membranes by pH-responsive antimicrobial peptides

2017

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The indiscriminate use of conventional antibiotics is leading to an increase in the number of resistant bacterial strains, motivating the search for new compounds to overcome this challenging problem. Antimicrobial peptides, acting only in the lipid phase of membranes without requiring specific membrane receptors as do conventional antibiotics, have shown great potential as possible substituents of these drugs. These peptides are in general rich in basic and hydrophobic residues forming an amphipathic structure when in contact with membranes. The outer leaflet of the prokaryotic cell membrane is rich in anionic lipids, while the surface of the eukaryotic cell is zwitterionic. Due to their positive net charge, many of these peptides are selective to the prokaryotic membrane. Notwithstanding this preference for anionic membranes, some of them can also act on neutral ones, hampering their therapeutic use. In addition to the electrostatic interaction driving peptide adsorption by the membrane, the ability of the peptide to perturb lipid packing is of paramount importance in their capacity to induce cell lysis, which is strongly dependent on electrostatic and hydrophobic interactions. In the present research, we revised the adsorption of antimicrobial peptides by model membranes as well as the perturbation that they induce in lipid packing. In particular, we focused on some peptides that have simultaneously acidic and basic residues. The net charges of these peptides are modulated by pH changes and the lipid composition of model membranes. We discuss the experimental approaches used to explore these aspects of lipid membranes using lipid vesicles and lipid monolayer as model membranes.

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The Single GUV Method for Probing Biomembrane Structure and Function

Cited by 16 publications

References 25 publications

Single GUV Method Reveals Interaction of Tea Catechin (−)-Epigallocatechin Gallate with Lipid Membranes

Single GUV Method Reveals Interaction of Tea Catechin (−)-Epigallocatechin Gallate with Lipid Membranes

Formation of Cell Membrane Component Domains in Artificial Lipid Bilayer

Lipid-packing perturbation of model membranes by pH-responsive antimicrobial peptides

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