Cooperativity of glycolipid phase transitions: a critical comparison of results from equilibrium X-ray, density and microcalorimetric measurements

Köberl, Mathias; Schöppe, Arnulf; Hinz, Hans‐Jürgen; Rapp, Gert

doi:10.1016/s0009-3084(98)00063-2

Cited by 13 publications

(15 citation statements)

References 30 publications

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“…Similar concentration dependency of phase transition enthalpy of DPPC bilayer was reported in the DPPC/lung surfactants interactions . In addition, a cooperative unit allows the estimation of the number of DPPC molecules undergoing the gel−liquid crystalline transition simultaneously. , Pure DPPC MLV dispersions have a high cooperative unit during the main phase transition (0% mole fraction) . The strong interactions between the DPPC bilayer and associative foreign molecules always reduce the number of molecules undertaking simultaneous phase transition and drive down the cooperative unit. ,, At all chitosan mole fractions, chitosan association on the DPPC bilayer surface caused serious disorganization on the ordered bilayer structure and resulted in significant reduction of the cooperative unit.…”

Section: Discussionmentioning

confidence: 53%

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Chitosan-Induced Perturbation of Dipalmitoyl-sn-glycero-3-phosphocholine Membrane Bilayer

2001

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Recently, chitosan, a positively charged polysaccharide in slightly acidic condition, has been used as a membrane perturbant in a novel gene delivery assay. In this study, the fundamental interactions between chitosan and DPPC membrane bilayers were investigated with cross-polarization microscopy, differential scanning calorimetry and Fourier transform (FT) Raman spectroscopy. The cross-polarized images showed that chitosan induced fusions of multilamellar vesicles. It was determined that the mixing of chitosan with dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and subsequent hydration of the mixture at 60 °C significantly suppressed the enthalpy of the gel-liquid crystalline transition in a concentration-dependent manner. Chitosan also affected the thermotropic behavior of DPPC bilayer during the cooling cycle. However, chitosan addition to DPPC had no effect on the main phase transition temperature (Tm) of DPPC bilayers. When DPPC and chitosan were mixed in chloroform before hydration, the initial rate of enthalpy reduction against chitosan concentration was significantly increased. Furthermore, the dependence of the cooperative unit of the DPPCs main transition on the chitosan mole fraction showed that chitosan tuned the intermolecular interactions between neighboring lipid molecules. FT-Raman spectroscopy provided solid evidence that the attractive interchain and intermolecular forces of the hydrophobic core (acyl chains) in the DPPC bilayer were significantly reduced by the chitosan-membrane interactions. The addition of chitosan also reduced the order in the two-dimensional packing of the acyl chains and increased the fluidity of the DPPC bilayer. This study provided new insights into the physicochemical interactions between model membrane and chitosan that might aid the development of a novel membrane perturbant for gene delivery.

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Section: Discussionmentioning

confidence: 53%

“…The calorimetric enthalpy in the main transition and the corresponding phase transition temperature of the samples were determined with Universal Analysis Software (TA Instrument). The calculations of the Van't Hoff enthalpy and cooperative unit (the ratio of Van't Hoff and calorimetric enthalpy) were based on procedures described elsewhere. , …”

Section: Methodsmentioning

confidence: 99%

Chitosan-Induced Perturbation of Dipalmitoyl-sn-glycero-3-phosphocholine Membrane Bilayer

2001

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“…Besides Guerbet glycolipids, there are other synthetic double-chain glycosides of similar chain lengths such as glycosyl–glycerol (dialkyl/diacyl) lipids that are the oxy analogues of the Guerbet kinds and have been studied extensively. − The elimination of the oxygen atoms in the glycerol/hydrocarbon chain interface reduces the melting temperature of the former compared to that of the latter kinds. This suggests that the oxygen atoms at the glycosyl–glycerol linkage increase the hydrogen bonding network in the hydrophilic region and raise the lipid melting point …”

Section: Resultsmentioning

confidence: 99%

Investigation of the Effect of Sugar Stereochemistry on Biologically Relevant Lyotropic Phases from Branched-Chain Synthetic Glycolipids by Small-Angle X-ray Scattering

et al. 2013

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Synthetic branched-chain glycolipids are suitable as model systems in understanding biological cell membranes, particularly because certain natural lipids possess chain branching. Herein, four branched-chain glycopyranosides, namely, 2-hexyl-decyl-α-D-glucopyranoside (α-Glc-OC10C6), 2-hexyl-decyl-β-D-glucopyranoside (β-Glc-OC10C6), 2-hexyl-decyl-α-D-galactopyranoside (α-Gal-OC10C6), and 2-hexyl-decyl-β-D-galactopyranoside (β-Gal-OC10C6), with a total alkyl chain length of 16 carbon atoms have been synthesized, and their phase behavior has been studied. The partial binary phase diagrams of these nonionic surfactants in water were investigated by optical polarizing microscopy (OPM) and small-angle X-ray scattering (SAXS). The introduction of chain branching in the hydrocarbon chain region is shown to result in the formation of inverse structures such as inverse hexagonal and inverse bicontinuous cubic phases. A comparison of the four compounds showed that they exhibited different polymorphism, especially in the thermotropic state, as a result of contributions from anomeric and epimeric effects according to their stereochemistry. The neat α-Glc-OC10C6 compound exhibited a lamellar (Lα) phase whereas dry α-Gal-OC10C6 formed an inverse bicontinuous cubic Ia3d (QII(G)) phase. Both β-anomers of glucoside and galactoside adopted the inverse hexagonal phase (HII) in the dry state. Generally, in the presence of water, all four glycolipids formed inverse bicontinuous cubic Ia3d (QII(G)) and Pn3m (QII(D)) phases over wide temperature and concentration ranges. The formation of inverse nonlamellar phases by these Guerbet branched-chain glycosides confirms their potential as materials for novel biotechnological applications such as drug delivery and crystallization of membrane proteins.

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“…The physicochemical properties of glycoamphiphiles have sometimes been shown to be very sensitive to small details in their sugar composition, in putative connection to extensive hydrogen bonding between neighboring headgroups and with the surrounding water. Also, the sugar-headgroup conformation was hypothesized to be effective in favoring or disfavoring side–side interaction between sugar rings, also influencing the extent and kinetics of water penetration into the hydrophilic layer. − …”

Section: Introductionmentioning

confidence: 99%

“… a Aggregation number N , area per headgroup at the interface A , polar and apolar volumes of the ganglioside molecule V pol and V apol , and number of dissociable sialic acid groups per molecule N sial . Results, obtained by laser light scattering measurements, are from ref . …”

Section: Introductionmentioning

confidence: 99%

Optimizing the Crowding Strategy: Sugar-Based Ionic Micelles in the Dilute-to-Condensed Regime

et al. 2014

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In the present study, we explore the effect of concentration on micelles made by different gangliosides, which are ionic biological glycolipids bearing multisugar headgroups with huge steric hindrance. Moreover, strong preferential interactions exist among like-conformer headgroups that can keep the ganglioside micelles in a trapped configuration. We extend the well-known ionic-amphiphiles paradigm, where local condensation and micelle crowding are matched by forming larger aggregates at increasing concentration. In fact, we force the balance between interparticle and intraparticle interactions while allowing for like conformers to modulate rebalancing. In the vast experimental framework, obtained by Small Angle X-ray scattering (SAXS) experiments, a theoretical model, accounting for a collective conformational transition of the bulky headgroups, is developed and successfully tested. It allows us to shed some light on the nature and coupling of the intermolecular forces involved in the interactions among glycolipid micelles. Energy minimization leads to complex behavior of the aggregation number on increasing concentration, fully consistent with the experimental landscape. From a biological perspective, this result could be reflected in the properties of ganglioside-enriched rafts on cell membranes, with a nonlinear structural response to approaching bodies such as charged proteins.

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Cooperativity of glycolipid phase transitions: a critical comparison of results from equilibrium X-ray, density and microcalorimetric measurements

Cited by 13 publications

References 30 publications

Chitosan-Induced Perturbation of Dipalmitoyl-sn-glycero-3-phosphocholine Membrane Bilayer

Chitosan-Induced Perturbation of Dipalmitoyl-sn-glycero-3-phosphocholine Membrane Bilayer

Investigation of the Effect of Sugar Stereochemistry on Biologically Relevant Lyotropic Phases from Branched-Chain Synthetic Glycolipids by Small-Angle X-ray Scattering

Optimizing the Crowding Strategy: Sugar-Based Ionic Micelles in the Dilute-to-Condensed Regime

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