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Brenac L, Baidoo EEK, Keasling JD, Budin I. Distinct functional roles for hopanoid composition in the chemical tolerance of Zymomonas mobilis. Mol Microbiol 2019; 112:1564-1575. [PMID: 31468587 DOI: 10.1111/mmi.14380] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2019] [Indexed: 11/29/2022]
Abstract
Hopanoids are a class of membrane lipids found in diverse bacterial lineages, but their physiological roles are not well understood. The ethanol fermenter Zymomonas mobilis features the highest measured concentration of hopanoids, leading to the hypothesis that these lipids can protect against the solvent toxicity. However, the lack of genetic tools for manipulating hopanoid composition in this bacterium has limited their further functional analysis. Due to the polyploidy (>50 genome copies per cell) of Z. mobilis, we found that disruptions of essential hopanoid biosynthesis (hpn) genes act as genetic knockdowns, reliably modulating the abundance of different hopanoid species. Using a set of hpn transposon mutants, we demonstrate that both reduced hopanoid content and modified hopanoid polar head group composition mediate growth and survival in ethanol. In contrast, the amount of hopanoids, but not their head group composition, contributes to fitness at low pH. Spectroscopic analysis of bacterial-derived liposomes showed that hopanoids protect against several ethanol-driven phase transitions in membrane structure, including lipid interdigitation and bilayer dissolution. We propose that hopanoids act through a combination of hydrophobic and inter-lipid hydrogen bonding interactions to stabilize bacterial membranes during solvent stress.
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Affiliation(s)
- Léa Brenac
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA, 94608, USA
| | - Edward E K Baidoo
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA, 94608, USA
| | - Jay D Keasling
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA, 94608, USA.,Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.,Department of Chemistry, University of California, Berkeley, CA, 94720, USA.,Department of Bioengineering, University of California, Berkeley, CA, 94720, USA.,QB3 Institute, University of California, Berkeley, CA, 94270, USA.,Biological Systems & Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,The Novo Nordisk Foundation Center for Sustainability, Technical University of Denmark, Lyngby, Denmark.,Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes for Advanced Technologies, Shenzhen, China
| | - Itay Budin
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA, 94608, USA.,Department of Chemical & Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA.,Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, CA, 92093, USA
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Sato T, Kojima K, Ihda TA, Sunamoto J, Ottenbrite RM. Macrophage Activation by Poly(maleic acid-alt-2-cyclohexyl-1,3-dioxap-5-ene) Encapsulated in Polysaccharide-Coated Liposomes. J BIOACT COMPAT POL 2016. [DOI: 10.1177/088391158600100403] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An increase in the efficiency of macrophage activation has been tried by en capsulating potent polyanionic polymer immunomodulators into polysac charide-coated liposomes. For this purpose, several alternating copolymers of maleic acid (MA) and itaconic acid (IT) with 2-cyclohexyl-1,3-dioxap-5-ene (CDA), styrene (ST), and other monomers have been synthesized and frac tionated. First, the interaction between the liposomes and polyanionic polymers was investigated. As a result, poly(maleic acid-alt-2-cyclohexyl-1,3-dioxap-5-ene) (MA-CDA) was found to be the best candidate for encapsulating in the liposome while poly(itaconic acid-alt-styrene)(IA-ST) strongly perturbed these vesicles. Based on these results, MA-CDA was encapsulated in the mannan derivative- coated liposomes and the macrophage activation activity was evaluated from the superoxide production of the activated macrophages in vivo. Compared with the administration of free MA-CDA, the maximum in the superoxide pro duction appeared faster (2 h after injection) and the activity was significantly increased.
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Affiliation(s)
- Toshinori Sato
- Laboratory of Artificial Cell Technology Department of Industrial Chemistry Faculty of Engineering, Nagasaki University Nagasaki 852, Japan
| | - Kazuyuki Kojima
- Laboratory of Artificial Cell Technology Department of Industrial Chemistry Faculty of Engineering, Nagasaki University Nagasaki 852, Japan
| | - Taka-Aki Ihda
- Laboratory of Artificial Cell Technology Department of Industrial Chemistry Faculty of Engineering, Nagasaki University Nagasaki 852, Japan
| | - Junzo Sunamoto
- Laboratory of Artificial Cell Technology Department of Industrial Chemistry Faculty of Engineering, Nagasaki University Nagasaki 852, Japan
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Wikström M, Kelly AA, Georgiev A, Eriksson HM, Klement MR, Bogdanov M, Dowhan W, Wieslander A. Lipid-engineered Escherichia coli membranes reveal critical lipid headgroup size for protein function. J Biol Chem 2009; 284:954-65. [PMID: 18981182 PMCID: PMC2613627 DOI: 10.1074/jbc.m804482200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 10/23/2008] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli membranes have a substantial bilayer curvature stress due to a large fraction of the nonbilayer-prone lipid phosphatidylethanolamine, and a mutant (AD93) lacking this lipid is severely crippled in several membrane-associated processes. Introduction of four lipid glycosyltransferases from Acholeplasma laidlawii and Arabidopsis thaliana, synthesizing large amounts of two nonbilayer-prone, and two bilayer-forming gluco- and galacto-lipids, (i) restored the curvature stress with the two nonbilayer lipids, and (ii) diluted the high negative lipid surface charge in all AD93 bilayers. Surprisingly, the bilayer-forming diglucosyl-diacylglycerol was almost as good in improving AD93 membrane processes as the two nonbilayer-prone glucosyl-diacylglycerol and galactosyl-diacylglycerol lipids, strongly suggesting that lipid surface charge dilution by these neutral lipids is very important for E. coli. Increased acyl chain length and unsaturation, plus cardiolipin (nonbilayer-prone) content, were probably also beneficial in the modified strains. However, despite a correct transmembrane topology for the transporter LacY in the diglucosyl-diacylglycerol clone, active transport failed in the absence of a nonbilayer-prone glycolipid. The corresponding digalactosyl-diacylglycerol bilayer lipid did not restore AD93 membrane processes, despite analogous acyl chain and cardiolipin contents. Chain ordering, probed by bis-pyrene lipids, was substantially lower in the digalactosyl-diacylglycerol strain lipids due to its extended headgroup. Hence, a low surface charge density of anionic lipids is important in E. coli membranes, but is inefficient if the headgroup of the diluting lipid is too large. This strongly indicates that a certain magnitude of the curvature stress is crucial for the bilayer in vivo.
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Affiliation(s)
- Malin Wikström
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
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4
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Björkbom A, Yamamoto T, Kaji S, Harada S, Katsumura S, Slotte JP. Importance of the phosphocholine linkage on sphingomyelin molecular properties and interactions with cholesterol; a study with phosphate oxygen modified sphingomyelin-analogues. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1501-7. [DOI: 10.1016/j.bbamem.2008.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 03/03/2008] [Accepted: 03/03/2008] [Indexed: 12/16/2022]
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5
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Asai Y. Investigation on the relationship between the physicochemical properties of particles composed of a novel lipid A analog, E5531, and its pharmacokinetics. ADV POWDER TECHNOL 2005. [DOI: 10.1163/1568552054194177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Orädd G, Rilfors L, Lindblom G. Initial acyl chain segments of gluco- and phospholipids differ in ordering in both lamellar and reversed hexagonal phases. Phys Chem Chem Phys 2001. [DOI: 10.1039/b106018j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Asai Y, Watanabe S. The effect of lipid A analog E5531 on membrane properties of dipalmitoylphosphatidylcholine. Drug Dev Ind Pharm 2000; 26:907-12. [PMID: 10900550 DOI: 10.1081/ddc-100101317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The effect of the lipid A analog E5531 on the phospholipid membrane was determined and compared with that of the lipid A from Escherichia coli (EC). E5531 decreased the phase transition temperature of dipalmitoylphosphatidylcholine (DPPC) membrane and increased the fluidity and permeability. On the other hand, EC increased the phase transition temperature and decreased the membrane fluidity and permeability. These results suggest that the reason for the difference of biological effects of E5531 and lipid A from EC would be caused by the differences from the effect on the cell membranes.
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Affiliation(s)
- Y Asai
- Formulation Research Laboratory, Kawashima, Eisai Company, Limited, Gifu, Japan
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8
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Asai Y, Nomura T, Murahashi N, Iwamoto K. Characterization of the physicochemical properties of the micelles of platelet-activating factor (C18:0). Drug Dev Ind Pharm 2000; 26:671-4. [PMID: 10826115 DOI: 10.1081/ddc-100101282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The purpose of this study was to clarify the physicochemical properties of the micelles of platelet-activating factor (PAF; C18:0). The critical micelle concentration (CMC) of PAF (C18:0) was determined (0.20 microM) using fluorescence techniques. The fluidity and the micropolarity of the PAF (C18:0) micelle were similar to those of the micelle of stearoyl lysophosphatidylcholine.
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Affiliation(s)
- Y Asai
- Formulation Research Laboratory, Kawashima, Eisai Company, Limited, Gifu, Japan
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Asai Y, Sano Y, Kikuchi K, Iwamoto K, Watanabe S. The effect of divalent cations on the membrane properties and pharmacokinetics in rat of the lipid A analogue E5531. J Pharm Pharmacol 2000; 52:39-45. [PMID: 10716601 DOI: 10.1211/0022357001773661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
To obtain information on the effects of Ca2+ on the membrane properties of the lipid A analogue E5531, we have determined the aggregate size, zeta potential, membrane fluidity, micropolarity and permeability of the E5531 membrane as a function of Ca2+ levels. Within the molar ratios of [Ca2+]/[E5531] = 1 and 3, Ca2+ increased the zeta potential of the E5531 membrane but had no effect on aggregate size (approximately 20 nm). Within the above ratios, Ca2+ decreased the membrane fluidity, as measured by micropolarity of E5531 and increased the phase transition temperature. The pharmacokinetics in rats for these samples with different membrane fluidity, prepared by changing the pre-dose formulation concentration of Ca2+, was determined and a correlation between membrane fluidity and pharmacokinetics was clearly observed. It thus appears that Ca2+ effects the membrane fluidity of E5531 as well as its pharmacokinetics in rats.
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Affiliation(s)
- Y Asai
- Formulation Research Laboratory, Kawashima, Eisai Co., Ltd, Gifu, Japan
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10
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Asai Y, Watanabe S. Effect of divalent cations on the membrane properties of the lipid A analog E5531. Drug Dev Ind Pharm 1999; 25:1107-13. [PMID: 10529891 DOI: 10.1081/ddc-100102276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
To obtain information on the effects of Mg2+ on the membrane properties of the lipid A analog E5531, we determined the size, structure, zeta potential, membrane fluidity, and micropolarity of the aggregates and the permeability of the E5531 membrane after the addition of Mg2+. E5531 forms a vesicle structure and within the molar ratio of [E5531]:[Mg2+] = 1:3, Mg2+ increased the zeta potential of the E5531 membrane, but did not change the size of the aggregates (approximately 20 nm). Within that molar ratio, Mg2+ decreased the membrane fluidity and micropolarity of E5531 and increased the phase transition temperature. Above the molar ratio of [E5531]:[Mg2+] = 1:5, the size of the aggregates was increased, but at [E5531]:[Mg2+] = 1:3, the size of the aggregates was similar to that in the absence of Mg2+ (approximately 20 nm), and we could stabilize the aggregates in rat plasma.
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Affiliation(s)
- Y Asai
- Formulation Research Laboratory, Kawashima, Eisai Company, Limited, Gifu, Japan
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11
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Asai Y, Watanabe S. Preparation of transparent injectable formulation for lipid A analog E5531. Drug Dev Ind Pharm 1999; 25:975-82. [PMID: 10518237 DOI: 10.1081/ddc-100102260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We developed a "pH-jump method" to obtain transparent solutions of E5531, a synthetic lipid A analog, at neutral pH for pharmaceutical injection. E5531 has two pKa: pKa1 = 6.0 and pKa2 = 9.3. At pH 11.0, E5531 was dispersed as a dissociated form, and the phase transition temperature Tc of E5531 was determined to be 30 degrees C using differential scanning calorimetry (DSC). Based on these results, the pH-jump method procedure involves dispersing E5531 at pH 11.0 (above pKa2) at 50 degrees C (above Tc) and mixing with a phosphate buffer to neutralize the pH. No degradated products of E5531 were observed at 50 degrees C for 3 hr during dispersing in the alkaline solution. The turbidity of samples prepared with the pH-jump method was similar to that of water and superior to the samples dispersed directly in neutral pH. This method does not need mechanical power and is suitable for large-scale production.
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Affiliation(s)
- Y Asai
- Formulation Research Laboratory, Kawashima, Eisai Company, Limited, Gifu, Japan
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12
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Asai Y, Iwamoto K, Watanabe S. Characterization of the physicochemical properties of aggregates of the lipid A analog, E5531, prepared by a ‘pH-jump method’. Chem Phys Lipids 1999. [DOI: 10.1016/s0009-3084(98)00100-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Asai Y, Iwamoto K, Watanabe S. The effect of the lipid A analog E5531 on phospholipid membrane properties. FEBS Lett 1998; 438:15-20. [PMID: 9821951 DOI: 10.1016/s0014-5793(98)01262-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In order to determine the effect of the lipid A analog, E5531, on phospholipid membranes, we used dipalmitoylphosphatidylcholine (DPPC) and investigated the physicochemical interaction between E5531 and DPPC membranes. E5531 and DPPC are miscible in the bulk phase at 25 degrees C. Within the E5531 mole fraction range (X(E5531)) of 0-0.5, E5531 decreased the zeta potentials of DPPC membranes but did not change the size of the DPPC liposomes. E5531/DPPC mixtures formed liposome-like structures. E5531 increased the fluidity of the DPPC membrane and decreased pyrene diffusion in the membrane. E5531 decreased the phase transition temperature and the cooperative interactions between DPPC molecules. These effects of E5531 on phospholipid membranes were different from those of lipid A from Escherichia coli and Salmonella minnesota.
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Affiliation(s)
- Y Asai
- Formulation Research Laboratory, Kawashima, Eisai Co., Ltd, Gifu, Japan
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14
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Asai Y, Iwamoto K, Watanabe S. Development of a dispersal procedure for the lipid A analog E5531 using a `pH-jump method'. Int J Pharm 1998. [DOI: 10.1016/s0378-5173(98)00131-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Giulieri F, Guillod F, Greiner J, Krafft MP, Riess JG. Anionic Glucophospholipids—A New Family of Tubule-Forming Amphiphiles. Chemistry 1996. [DOI: 10.1002/chem.19960021022] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Guillod F, Greiner J, Riess JG. Vesicles made of glycophospholipids with homogeneous (two fluorocarbon or two hydrocarbon) or heterogeneous (one fluorocarbon and one hydrocarbon) hydrophobic double chains. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1282:283-92. [PMID: 8703984 DOI: 10.1016/0005-2736(96)00067-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The vesicle-forming ability of the new anionic double chain glycophospholipids 1-4, with either two hydrocarbon or two perfluorocarbon chains, or a mixed double chain (one fluorinated, one hydrogenated), was investigated. When dispersed in water, 1a-c,e, 2b,c and 4b,c readily gave heat-sterilizable vesicles, 30-70 nm in diameter. The galactose and mannose-based fluorinated vesicles were also highly stable on aging. The 6-substituted glucose derivatives 3 formed tubules that reversibly interconverted into vesicles, depending on temperature. The leakage rate in buffer of carboxyfluorescein or calcein from vesicles made from 1a-c,e 2b,c and 4b,c depended on the sugar (t1/2 galactose > mannose > glucose). It decreased significantly with increasing fluorination and length of the hydrophobic tails. The mixed perfluorocarbon/hydrocarbon-tailed amphiphiles were found to be miscible with both the two fluorocarbon chains and the two hydrocarbon chains derivatives. Such admixing tended, however, to increase the small unilamellar vesicles' permeability. In buffered serum, all the vesicles investigated were highly permeable, but incorporation of cholesterol or DSPC in vesicles made of 1e significantly reduced their permeability in serum. The new vesicle and membrane components have i.v. maximum tolerated doses as high as 500 mg/kg body weight in mice; hemolytic activity sharply decreases with increasing degree of fluorination.
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Affiliation(s)
- F Guillod
- Unité de Chimie Moléculaire, Université de Nice-Sophia Antipolis, CNRS URA 426, Nice, France
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17
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Li ZC, Li FM, Arase S, Takeoka S, Tsuchida E. Effect of a Lithocholic Acid Derivative on the Molecular Packing and Stability of Phospholipid Vesicles. CHEM LETT 1994. [DOI: 10.1246/cl.1994.2199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Freeze drying of liposomes with free and membrane-bound cryoprotectants — the background of protection and damaging processes. Int J Pharm 1994. [DOI: 10.1016/0378-5173(94)90447-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Abstract
LIPIDAT is a computerized database providing access to the wealth of information scattered throughout the literature concerning synthetic and biologically derived polar lipid polymorphic and mesomorphic phase behavior. The database is considered comprehensive for glycerophospholipids, glycoglycerolipids, sphingolipids and natural membrane extracts. Here, a review of the LIPIDAT data subset referring to glycoglycerolipids is presented together with an analysis of these data. The glycoglycerolipids subset represents 4% of all LIPIDAT records. It includes data collected over a 20-year period and consists of 419 records obtained from 37 articles in 13 journals. An analysis of the data in the subset has allowed us to identify trends in hydrated glycoglycerolipids phase behavior reflecting differences in hydrocarbon chain length, chain branching, chain-glycerol linkage type (ether vs. ester), sugar headgroup-glycerol linkage type (alpha vs. beta) and sugar headgroup identity. Included is a summary of the data concerning the effect of pH and of stereochemical purity on glycoglycerolipid phase behavior. Information on the mesomorphism of biologically derived and dry glycoglycerolipids is also presented. This review includes 92 references.
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Affiliation(s)
- R Koynova
- Department of Chemistry, Ohio State University, Columbus 43210-1173
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20
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Abstract
It should be clear from this summary that we currently know a great deal about the organization and dynamics of the lipids in mycoplasma membranes in general, and in the cell membrane of A. laidlawii in particular. In fact, research on mycoplasma membranes has been important in unambiguously establishing the fundamental lipid bilayer structure of all biological membranes and in elucidating some of the major properties of bilayers in biomembranes, such as their thermotropic phase behavior and interactions with cholesterol and membrane proteins. Although a great deal has been learned, a number of issues have not been fully resolved. In particular, the concept of membrane lipid fluidity must be refined and quantitated, and the relationship between orientational order and rates of motion better understood. This will require that the apparent discrepancies between some of the results obtained, for example, by the various spectroscopic techniques, be resolved. In particular, the nature of the boundary lipid surrounding integral membrane proteins will require further study, as will the question of the specificity of lipid-protein interactions. Also, accurate quantitative measurements for the lateral and rotational mobilities of the various lipid components in the mycoplasma membranes have not yet been made. Although not reviewed in this chapter, the related questions of the in vivo rate of phospholipid, glycolipid, and cholesterol transverse diffusion (flip-flop), and the possible asymmetric transbilayer distribution of these components in mycoplasma membranes, are still not well understood. Although much remains to be done, particularly with respect to our understanding of protein structure and function in mycoplasma membranes, a solid basis for further advances has now been laid. The many natural advantages of mycoplasma for biochemical and biophysical investigations of membrane structure and function should continue to make these organisms very useful for membrane studies for years to come.
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Affiliation(s)
- R N McElhaney
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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21
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Rilfors L, Wieslander A, Lindblom G. Regulation and physicochemical properties of the polar lipids in Acholeplasma laidlawii. Subcell Biochem 1993; 20:109-66. [PMID: 8378987 DOI: 10.1007/978-1-4615-2924-8_4] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- L Rilfors
- Department of Physical Chemistry, University of Umeå, Sweden
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22
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Biochemical and biophysical properties of thylakoid acyl lipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(09)91002-7] [Citation(s) in RCA: 189] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Webb MS, Green BR. Effects of neutral and anionic lipids on digalactosyldiacylglycerol vesicle aggregation. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1030:231-7. [PMID: 2261485 DOI: 10.1016/0005-2736(90)90299-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have previously reported that large unilamellar liposomes made from the neutral galactolipid digalactosyldiacylglycerol (DGDG) will aggregate in the presence of monovalent or divalent cations, behavior that would not have been predicted for an uncharged lipid (Webb et al. (1988) Biochim. Biophys. Acta 938, 323-333). In this paper, the effects of including the other major thylakoid lipids on the Mg2+ concentration required for aggregation of DGDG vesicles has been examined. Addition of the neutral, hexagonal-II phase preferring lipid monogalactosyldiacylglycerol (MGDG) to DGDG up to 50 mol% had no effect, suggesting that the MGDG head group is as effective in causing aggregation as the DGDG head group. Addition of 0.5 to 5.0 mol% of either of the two anionic lipids phosphatidylglycerol (PG) or sulfoquinovosyldiacylglycerol (SQDG) inhibited the aggregation of DGDG vesicles, probably by the development of an electrostatic potential. Phosphatidylcholine (PC) in amounts up to 25 mol% did not inhibit or promote aggregation. Vesicles with a composition similar to that of thylakoids (DGDG/MGDG/SQDG/PG, 1:2:0.5:0.5) required 65 mM MgCl2 in the presence of 200 mM KCl, i.e., higher concentrations than are present in the chloroplast stroma. If MGDG made up more than 25 mol% of any combination of lipids, vesicle aggregation could not be reversed by dilution. These results are consistent with cations playing a role in mediating the close approach of bilayers via an effect on head-group hydration and head-group interaction between bilayers.
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Affiliation(s)
- M S Webb
- Department of Botany, University of British Columbia, Vancouver, Canada
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Sunamoto J, Goto M, Iwamoto K, Kondo H, Sato T. Synthesis and characterization of 1,2-dimyristoylamido-1, 2-deoxyphosphatidylcholine as an artificial boundary lipid. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1024:209-19. [PMID: 2354176 DOI: 10.1016/0005-2736(90)90346-p] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The synthesis and characterization of an artificial boundary lipid, 1,2-dimyristoylamido-1,2-deoxyphosphatidylcholine (DDPC), are described. DDPC has two amide bonds instead of ester bonds of regular lecithins such as 1,2-dimyristoylphosphatidylcholine (DMPC). In differential scanning calorimetry (DSC) measurements, DDPC gave two endothermic peaks: one was at 18.0 degrees C (delta H = 10.74 kJ.mol-1) and the other at 23.0 degrees C (delta H = 12.91 kJ.mol-1). The former peak was sharp and considered to be the phase transition of the hydrocarbon region, while the latter was assigned to the melt of the hydrogen-belt formed by the amide groups of DDPC. Addition of DDPC to DMPC made the DMPC membrane less fluid in the region close to the surface, and significantly increased the reconstitution efficiency of glycophorin into the membrane. This effect of DDPC was much larger than that of naturally occurring lipid, sphingomyelin.
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Affiliation(s)
- J Sunamoto
- Department of Polymer Chemistry, Faculty of Engineering, Kyoto University, Japan
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Naito M, Utsumi H, Umeda M, Kudo I, Takeshita K, Hamada A, Nojima S, Inoue K. ESR study on synthetic glyceroglycolipid liposomal membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 985:147-52. [PMID: 2553114 DOI: 10.1016/0005-2736(89)90359-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We previously reported that glyceroglycolipid liposomes without cholesterol activated mouse peritoneal macrophages in vivo and in vitro, whereas glyceroglycolipid liposomes containing equimolar cholesterol did not. In order to characterize the properties of the glyceroglycolipid membranes, ESR spectroscopic studies were carried out with an acyl spin-labeled galactosyl ceramide (SL-GC) or a headgroup spin-labeled phospholipid (SL-6-DPPA) in 1,2-dipalmitoyl[beta-cellobiosyl-(1'---3)]glycerol (Cel-DAG) liposomal membranes. The ESR spectrum of the SL-GC in the Cel-DAG liposomes at 37 degrees C was a single broad line, indicating that the SL-GC molecules were excluded almost completely from Cel-DAG domains and formed clusters in the membranes. The spectrum of SL-6-DPPA in the Cel-DAG liposomes at 37 degrees C showed broad resonance lines with the central peak being the highest, while that at 60 degrees gave narrow lines with the low-field peak being the highest. This observation and rotational correlation time analysis showed that the molecular motions of spin-label moiety of the SL-6-DPPA were extremely restricted at 37 degrees C but not above Tc. These results suggest that below Tc the Cel-DAG molecules are packed tightly and restricted in motion in the membrane. Incorporation of cholesterol into the Cel-DAG liposomal membranes gave (1) the spectra of the SL-GC triplet, and (2) the spectra of the SL-6-DPPA narrow resonance with the low-field peak being the highest. These results suggest that cholesterol disturbs the rigid-packed structure of the Cel-DAG membrane and increases the molecular motions of the Cel-DAG. The DSC analysis of Cel-DAG with and without cholesterol agreed well to the results of the ESR technique. Thus we assume that peritoneal macrophages recognize the rigid-packed carbohydrate residues which are restricted in motion on the Cel-DAG membranes.
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Affiliation(s)
- M Naito
- Department of Health Chemistry, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan
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26
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Asgharian B, Cadenhead DA, Mannock DA, Lewis RN, McElhaney RN. A comparative monomolecular film study of 1,2-di-O-palmitoyl-3-O-(alpha- and beta-D-glucopyranosyl)-sn-glycerols. Biochemistry 1989; 28:7102-6. [PMID: 2819051 DOI: 10.1021/bi00443a047] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The polar headgroup contribution to monolayer behavior of dipalmitoylglucosylglycerol has been examined through studies of 1,2-di-O-palmitoyl-3-O-(alpha-D-glucopyranosyl)-sn-glycerol (di-16:0-alpha GlcDG) and 1,2-di-O-palmitoyl-3-O-(beta-D-glucopyranosyl)-sn-glycerol (di-16:0-beta GlcDG) in which the sugar headgroup is linked via an alpha or beta linkage to the diacylglycerol moiety. The results indicate that the limiting areas per molecule of the resultant condensed states are smaller than those of the corresponding phosphatidylcholine (DPPC) but larger than those of dipalmitoylphosphatidylethanolmine (DPPE). In the expanded state, while the areas per molecule are similar to those of DPPC at low pressures, both glycolipids occupy smaller areas at higher pressures. The expanded-state areas of the glucolipids are also slightly greater than those of DPPE. The initial compressional phase transition pressure of the glucolipid liquid-expanded/liquid-condensed transition (pi t) is, however, less sensitive to temperature than are the pi t values of phospholipids. Both of these effects must relate to strong headgroup/water interactions, which, in turn, result in a stabilization of the liquid-expanded states. In the expanded states the alpha anomers are slightly less tightly packed than the beta anomers, as is indicated by the somewhat higher areas per molecule of the expanded states and the lower transition temperatures. These differences in chain-melting temperatures are slightly smaller than those observed in bilayers. While the areas per molecule of the dipalmitoyl glucolipids are greater than those of dipalmitoylphosphatidylethanolamine, they nevertheless exhibit a greater tendency to form nonbilayer structures. Such observations indicate that other factors besides geometric shape play a role in bilayer/nonbilayer transitions.
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Affiliation(s)
- B Asgharian
- Department of Chemistry, State University of New York, Buffalo 14214
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27
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Carrier D, Giziewicz JB, Moir D, Smith IC, Jarrell HC. Dynamics and orientation of glycolipid headgroups by 2H-NMR: gentiobiose. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 983:100-8. [PMID: 2758044 DOI: 10.1016/0005-2736(89)90385-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Deuterium nuclear magnetic resonance has been used to investigate the dynamics and determine the orientation of the headgroup of the glycolipid 1,2-di-O-tetradecyl-3-O-(6-O-beta-D-glucopyranosyl-beta-D-glucopyranosyl )-sn- glycerol (beta-DTDGL), in aqueous multilamellar dispersions. In addition, its anomeric analog, having an alpha glucose-glycerol linkage, was prepared and examined. The lipids were labelled with deuterium at specific positions in the disaccharide moiety. Analysis of the deuterium quadrupolar splittings for the first glucose ring (glycerol-linked) gave segmental order parameters of 0.43 and 0.35 for the beta and alpha isomers, respectively. Both isomers had similar orientations of the sugar ring relative to the bilayer surface, as determined for lipid in the liquid-crystalline phase. 2H-NMR results for the lipid labelled at C-6' are consistent with a single conformation about the C-5'-C-6' bond of the first glucose residue, with a dihedral angle (O-5'-C-5'-C-6'-O-6') of -17 degrees. The results obtained for the second sugar ring suggest that two conformers may be present, which are in slow exchange on the 2H-NMR timescale. Measurements of longitudinal relaxation times, T1z, gave similar values for both sugar moieties in the headgroup, suggesting that the disaccharide does not exhibit the flexibility expected about the 1----6 linkage. Since T1z for 2H in these compounds decreases with increasing temperature and increases with magnetic field strength, the motion(s) dominating relaxation is in the long-correlation-time regime [omega 0 tau c)2 greater than 1). Thus, the gentiobiosyl headgroup undergoes the slowest motion of the glycolipid headgroups studied to date.
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Affiliation(s)
- D Carrier
- Division of Biological Sciences, National Research Council of Canada, Ottawa, Ontario
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28
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Carlsson A, Sato T, Sunamoto J. Physicochemical Stabilization of Lipid Microspheres by Coating with Polysaccharide Derivatives. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1989. [DOI: 10.1246/bcsj.62.791] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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29
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Renou JP, Giziewicz JB, Smith IC, Jarrell HC. Glycolipid membrane surface structure: orientation, conformation, and motion of a disaccharide headgroup. Biochemistry 1989; 28:1804-14. [PMID: 2719936 DOI: 10.1021/bi00430a057] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The orientation of the disaccharide headgroup of a lactose-containing lipid, 3-O-(4-O-beta-D-galactopyranosyl-beta-D-glucopyranosyl)-1,2-di-O-tetrade cyl-sn- glycerol (DTLL), relative to the surface of bilayer membranes has been determined via 2H NMR. The lactosyl headgroup is extended away from the membrane surface into the aqueous phase. The headgroup motion has axial symmetry as evidenced by the spectral line shape and order parameter tensor. 2H NMR of oriented multibilayers of DTLL confirms that the director of motional averaging is the bilayer normal. The two sugar residues have segmental order parameters S (glucose, 0.53; galactose, 0.51) which indicate that the headgroup fluctuates about the bilayer normal as a rigid unit. 2H spin-lattice relaxation times T1z for deuterons on each of the two sugar rings are similar, indicating further that there is no substantial motion about the disaccharide linkage within the headgroup. The magnitude of the relaxation times (4 ms) suggests that the rigid body motions of the headgroup are approaching the Larmor frequency; however, they increase with increasing temperature, indicating that the motions are rapid enough to be in the fast motional regime (omega o2 tau c2 less than 1). The conformation about the galactose-glucose intersaccharide linkage, calculated from the 2H NMR data, is shown to differ substantially from those found in X-ray diffraction studies of crystalline lactose and high-resolution NMR studies of methyl lactoside in nonviscous solution. The orientations of the hydroxymethyl groups in the headgroup have been calculated from the 2H NMR data. For the galactosyl residue the data are consistent with the presence of more than one rotamer about the C5"-C6" bond which are in fast exchange on the 2H NMR time scale. The hydroxymethyl group of the glucose residue exists in two rotameric forms about the C5'-C6' bond which have relative populations of ca. 2:1 and which are in slow exchange on the 2H NMR time scale (10(-5) s). The two rotamers differ from those deduced from X-ray crystallography of crystalline lactose and 13C NMR studies of methyl lactoside in solution.
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Affiliation(s)
- J P Renou
- Division of Biological Sciences, National Research Council of Canada, Ottawa, Ontario
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30
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Hagiwara A, Takahashi T, Oku N. Cancer chemotherapy administered by activated carbon particles and liposomes. Crit Rev Oncol Hematol 1989; 9:319-50. [PMID: 2688681 DOI: 10.1016/s1040-8428(89)80017-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In cancer chemotherapy, a specific drug delivery system is expected since many anticancer drugs show toxicity against not only cancer cells but also against normal tissues. The dosage form comprising anticancer drugs adsorbed on activated carbon particles or encapsulated in liposomes is developed as a drug-delivery system which enhances the therapeutic efficacy and reduces the adverse effects. The dosage forms are versatile in size and electric charge, so that large amounts of the drugs are distributed to the "targeted" organs or tissues and lesser amounts are distributed to the whole body. The dosage forms are designed to release the drugs slowly for a long time at local sites. Through this process, practical use of the dosage forms as an anticancer drug carrier results in an enhancement of anticancer efficacy on the local lesion and a decrease of systemic toxicity.
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Affiliation(s)
- A Hagiwara
- 1st Department of Surgery, Kyoto Prefectural University of Medicine, Japan
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31
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Koynova RD, Kuttenreich HL, Tenchov BG, Hinz HJ. Influence of head-group interactions on the miscibility of synthetic, stereochemically pure glycolipids and phospholipids. Biochemistry 1988; 27:4612-9. [PMID: 3167003 DOI: 10.1021/bi00413a005] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Phase diagrams of binary mixtures of the glycoglycerolipids 1,2-di-O-tetradecyl-3-O-beta-D-galactosyl-sn-glycerol (14-Gal) and 1,2-di-O-tetradecyl-3-O-beta-D-glucosyl-sn-glycerol (14-Glc) with the phospholipids L-dimyristoylphosphatidylcholine (DMPC) and L-dimyristoylphosphatidylethanolamine (DMPE) were recorded by high-sensitivity differential scanning calorimetry and used for determination of the glycolipid-phospholipid miscibility in solid and liquid-crystalline states. As a consequence of a metastable behavior of both glycolipids and DMPE, the solid-state glycolipid/phospholipid miscibility was strongly dependent on the temperature prehistory of the samples. While DMPC and 14-Glc mix continuously, the other three binaries display extended regions of solid-solid-phase separation in the equilibrium low-temperature states. The DMPE/glycolipid phase diagrams were of clearly expressed eutectic type. Continuous solutions were formed in the liquid-crystalline and in the metastable solid phases of the mixtures. Simulations of the shape of the phase diagrams using the Bragg-Williams approximation showed certain deviations from ideal mixing in the liquid-crystalline continuous solutions. Since both glycolipids and phospholipids contain fully saturated fatty acids of equal chain length, their mixing properties were predominantly determined by the interactions between the lipid polar moieties, assuming the influence of ester or either linkages of the alkyl chains on the mixing parameters to be negligible. The clearly expressed differences in the mixing of 14-Glc and 14-Gal with phospholipids are most probably due to different hydrogen-bond networks formed by the glucosyl and galactosyl residues.
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Affiliation(s)
- R D Koynova
- Central Laboratory of Biophysics, Bulgarian Academy of Sciences, Sofia
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32
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Prado A, da Costa MS, Laynez J, Madeira VM. Physical properties of membrane lipids isolated from a thermophilic eubacterium (Thermus sp.). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 238:47-58. [PMID: 3250247 DOI: 10.1007/978-1-4684-7908-9_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Membranes from a thermophilic eubacterium, Thermus sp. strain SPS 11, isolated from thermal springs of São Pedro do Sul spa (Portugal), are characterized for having two main polar lipids, a glycolipid (GL) with four monosaccharide residues, which at 73 degrees C accounts for 95% of the carbohydrate in the total lipid extracts, and a glycophospholipid (PL) which at 73 degrees C accounts for about 90% of the lipid phosphorous. A complex mixture of carotenoids (CA) makes up 11% by weight of the total membrane lipids. The branched fatty acyl chains (iso C15 and iso C17) comprise about 90% of the alifatic moieties of the polar lipids of this bacterium. Moreover, when the growth temperature increases from 50 to 73 degrees C there is an increase of the iso C17/ iso C15 ratio and of the GL/PL ratio. We have studied the biophysical properties of bilayers (as multilamellar liposomes) prepared from GL, PL and the mixtures of PL, GL and CA in proportions found in the membranes of bacteria growing at their optimal growth temperature, using polarization of DPH fluorescence, low and wide-angle X-ray diffraction and differential scanning calorimetry. The three techniques agree in showing the presence of a broad phase transition from a gel (L beta) phase to a liquid-crystal (L alpha) phase between 8 and 30 degrees C, for all the lipid dispersions studied except for the GL. Although all the dispersions studied form a bilayer structure at all the temperatures studied, only the mixture of the three components (PL, GL + CA) avoids the phase separation present in the mixtures of PL + CA at temperatures lower than 30 degrees C and PL + GL at temperatures lower than 55 degrees C. Our results are compared with those of Pinheiro et al. (1978) obtained with the 31p-NMR technique and applied to the study of the same samples.
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Affiliation(s)
- A Prado
- Departamento de Bioquímica, Facultad de Ciencias, Universidad del País vasco, Spain
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33
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Sprague SG. Structural and functional consequences of galactolipids on thylakoid membrane organization. J Bioenerg Biomembr 1987; 19:691-703. [PMID: 3320041 DOI: 10.1007/bf00762303] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Photosynthetic membranes of higher plant chloroplasts are composed primarily of polar, but uncharged, galactolipids unlike most mammalian membranes which contain large amounts of phosphatidylcholine. It is unclear what role(s) the galactolipids play in maintaining the differentiated thylakoid membranes, or in stabilizing the photosynthetically active enzyme complexes. Some of the membrane complexes show no lipid selectivity for maintaining structural or functional integrity. Others are poisoned or dissociated in the presence of high concentrations of a trace lipid class. The efficiency of energy transfer and the reconstitution of protein complexes into liposomes are dependent on the lipid class employed. The lipids are asymmetrically arranged along and across the thylakoid membranes but not as distinctly as the proteins.
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Affiliation(s)
- S G Sprague
- Department of Biochemistry, West Virginia University, School of Medicine, Morgantown 26506
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Boggs JM. Lipid intermolecular hydrogen bonding: influence on structural organization and membrane function. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 906:353-404. [PMID: 3307919 DOI: 10.1016/0304-4157(87)90017-7] [Citation(s) in RCA: 566] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The great variety of different lipids in membranes, with modifications to the hydrocarbon chains, polar groups and backbone structure suggests that many of these lipids may have unique roles in membrane structure and function. Acidic groups on lipids are clearly important, since they allow interaction with basic groups on proteins and with divalent cations. Another important property of certain lipids is their ability to interact intermolecularly with other lipids via hydrogen bonds. This interaction occurs through acidic and basic moieties in the polar head groups of phospholipids, and the amide moiety and hydroxyl groups on the acyl chain, sphingosine base and sugar groups of sphingo- and glycolipids. The putative ability of different classes of lipids to interact by intermolecular hydrogen bonding, the molecular groups which may participate and the effect of these interactions on some of their physical properties are summarized in Table IX. It is frequently questioned whether intermolecular hydrogen bonding could occur between lipids in the presence of water. Correlations of their properties with their molecular structures, however, suggest that it can. Participation in intermolecular hydrogen bonding increases the lipid phase transition temperature by approx. 8-16 Cdeg relative to the electrostatically shielded state and by 20-30 Cdeg relative to the repulsively charged state, while having variable effects on the enthalpy. It increases the packing density in monolayers, possibly also in the liquid-crystalline phase in bilayers, and decreases the lipid hydration. These effects can probably be accounted for by transient, fluctuating hydrogen bonds involving only a small percentage of the lipid at any one time. Thus, rotational and lateral diffusion of the lipids may take place but at a slower rate, and the lateral expansion is limited. Intermolecular hydrogen bonding between lipids in bilayers may be significantly stabilized, despite the presence of water, by the fact that the lipids are already intermolecularly associated as a result of the hydrophobic effect and the Van der Waals' interactions between their chains. The tendency of certain lipids to self-associate, their asymmetric distribution in SUVs, their preferential association with cholesterol in non-cocrystallizing mixtures, their temperature-induced transitions to the hexagonal phase and their inhibitory effect on penetration of hydrophobic residues of proteins partway into the bilayer can all be explained by their participation in intermolecular hydrogen bonding interactions.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J M Boggs
- Department of Biochemistry, Hospital for Sick Children, Toronto, Canada
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Jarrell HC, Wand AJ, Giziewicz JB, Smith IC. The dependence of glyceroglycolipid orientation and dynamics on head-group structure. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 897:69-82. [PMID: 3801482 DOI: 10.1016/0005-2736(87)90316-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The head-group orientations and molecular dynamics of three glyceroglycolipids in aqueous dispersions, as determined by 2H-NMR, are compared. 1,2-Di-O-tetradecyl-3-O-(alpha-D-glucopyranosyl)-sn-glycerol (alpha-DTGL) and 1,2-di-O-tetradecyl-3-O-(alpha-D-mannopyranosyl)-sn-glycerol (alpha-DTML), selectively 2H-labelled on the pyranose ring, at the exocyclic hydroxymethyl group, and at C3 of glycerol, have been studied by 2H-NMR and the results compared with those reported earlier for 1,2-di-O-tetradecyl-3-O-(beta-D-glucopyranosyl)-sn-glycerol (beta-DTGL). The alpha-glucolipid exhibits a gel-to-liquid crystal phase transition and a lamellar to hexagonal mesophase transition at temperatures which are similar to those of the beta-anomer, beta-DTGL. However, alpha-DTGL exhibits head group orientations and molecular ordering in the lamellar and hexagonal phases which differ strikingly with those reported for the corresponding beta-glucolipid. Whereas the head group of beta-DTGL is extended away from the bilayer surface into the aqueous phase, that of alpha-DTGL is almost parallel to the bilayer surface. alpha-DTGL exhibits a molecular order parameter of 0.56 which is substantially greater than that of its anomer, beta-DTGL, 0.45. The latter indicates that the head group region of the alpha-glyceroglucolipid is characterized by smaller angular fluctuations than that of beta-DTGL. On entering the hexagonal mesophase the pyranose ring of the beta-glucolipid undergoes a large reorientation relative to the motional axis of the head group, whereas the alpha-anomer exhibits only a small orientational change. 1,2-Di-O-tetradecyl-3-O-(alpha-D-mannopyranosyl)-sn-glycerol (alpha-DTML) undergoes a phase transition at 47 degrees C, attributed to the unusual lamellar gel to hexagonal phase transition. The pyranose ring of alpha-DTML, in a mixture with dimyristoylphosphatidylcholine (1:9 mol ratio) to give a lamellar liquid crystalline phase, is oriented away from the bilayer surface into the aqueous environment and has an Smol of 0.75. The results for alpha-DTML, 2H-labelled at the C3 position of glycerol, suggest that this segment also has high molecular ordering. alpha-DTML in a lamellar environment has the least flexible membrane surface of the glyceroglycolipids investigated to date. 2H-NMR spin lattice relaxation times have been used to probe the head group motions of the glycolipids. The results indicate that the rate of head group motion increases in the order alpha-DTML less than alpha-DTGL less than beta-DTGL.(ABSTRACT TRUNCATED AT 400 WORDS)
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Abstract
The forces that hold cell membrane components together are non-covalent and thermodynamically favoured in aqueous media. Hence virtually any glycolipid or membrane glycoprotein might be expected to be incorporable into lipid bilayer membranes and this expectation has been borne out. In addition methods have been developed for linking lipid fragments to species that would not otherwise be expected to associate with bilayers. Techniques that have been successfully used to generate bilayer structures bearing glycolipids and glycoproteins include hydration of films dried down from non-aqueous solutions of the components, detergent removal from aqueous component solutions, exogenous addition to preformed membranes, and various organic solvent injection or reverse phase approaches. Bilayer association of glycolipids and membrane glycoproteins, with preservation of specific receptor function, seem easy to achieve--in fact difficult not to achieve. Optimization of receptor function to accurately mimic that of cell membranes and efficient preservation of functions such as transport or second messenger activation, are typically more demanding, although still feasible. A systematic approach can give considerable insight into the processes involved via identification of minimal necessary factors. Unfortunately, the actual relative arrangement of components, so critical to subtleties of glycolipid and glycoprotein function, remains almost totally unknown for lack of morphological information in the size range of individual macromolecules. The latter problem has come to be the most critical limitation to many studies.
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O'Connor CJ, Wallace RG, Iwamoto K, Taguchi T, Sunamoto J. Bile salt damage of egg phosphatidylcholine liposomes. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 817:95-102. [PMID: 4039949 DOI: 10.1016/0005-2736(85)90072-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Physiochemical damage of egg phosphatidylcholine liposomes, caused by the salts of three bile acids, chenodeoxycholic acid, ursodeoxycholic acid, and cholic acid, has been investigated. Of the three bile salts, that of chenodeoxycholic acid was the most destructive, and the effect of the damage was examined by monitoring the induced 6-carboxyfluorescein release from the liposomes. For all three of the bile salts and under the experimental conditions, the minimum (effective) concentrations causing the 6-carboxyfluorescein release were below their critical micelle concentrations. In the case of the salt of chenodeoxycholic acid, the presence of cholesterol in the liposomal bilayers did not show any significant effect on the induced 6-carboxyfluorescein release, while, for the salts of ursodeoxycholic acid and cholic acid, the presence of cholesterol tended to depress the release. Permeation of bile salts into the membranes of liposomal bilayers made these membranes more fluid, and this fluidity was monitored by measuring the change in fluorescence polarization using 1,6-diphenylhexatriene entrapped in the liposomes. Coating the liposomes with polysaccharides, to make them more hydrophobic, led to their easier lysis by the bile salts.
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Liposomal membranes. XX. Autoxidation of unsaturated fatty acids in liposomal membranes. ACTA ACUST UNITED AC 1985. [DOI: 10.1016/0005-2760(85)90262-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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40
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Peters MW, Mehlhorn IE, Barber KR, Grant CW. Evidence of a distribution difference between two gangliosides in bilayer membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 1984; 778:419-28. [PMID: 6548930 DOI: 10.1016/0005-2736(84)90389-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Freeze-etch electron microscopy, a platinum shadowing technique, has been used to compare the lateral distribution of several gangliosides in bilayer model membranes by directly visualizing bound lectin molecules. In particular, GM1 and GD1a, major components of brain ganglioside, were studied in phase-separated mixtures of dipalmitoyl- and dielaidoylphosphatidylcholines exposed to Ricinus communis agglutinin and wheat germ agglutinin. The distribution of glycolipid showed evidence of microheterogeneity in that bound lectin tended to occur in clusters of several or more molecules. With GD1a as receptor such clusters were small and very uniformly distributed over the membrane surface. Somewhat larger, irregularly spaced clusters of up to a dozen lectin particles were more typical of membranes bearing GM1 and, in addition, there were occasional extensive patches of bound lectin coexisting with areas apparently devoid of glycolipid receptor in phase-separated mixtures of dipalmitoyl- and dielaidoylphosphatidylcholine. Gangliosides in the latter mixtures were not obviously influenced in their lateral distribution by the presence of coexisting fluid and rigid domains. These basic observations seem to extend to bilayer membranes containing mixtures of two gangliosides. The patterns of lectin binding were not grossly affected by incubation time or history of warming and cooling. This study was extended to bilayers of pure dipalmitoylphosphatidylcholine in expectation that the distinctive features characteristic of the P beta' phase of this lipid might accentuate any behavioural differences between GM1 and GD1a. GM1 was found to exist preferentially in the 'trough' regions between P beta' ripples, while GD1a showed no apparent preferential arrangement. Given that bound lectins adequately reflect glycolipid distribution in membranes, it would appear that structurally different glycolipids from the same host membrane can assume different distributions on the basis of interactions with defined lipid host matrices.
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McElhaney RN. The structure and function of the Acholeplasma laidlawii plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 779:1-42. [PMID: 6318828 DOI: 10.1016/0304-4157(84)90002-9] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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