Thermodynamic and structural behaviour of equimolar POPC/CnE4 (n=8, 12, 16) mixtures by sorption gravimetry, 2H NMR spectroscopy and X-ray diffraction

Pfeiffer, Helge; Klose, G.; Heremans, Karel

doi:10.1016/j.chemphyslip.2009.12.005

Cited by 5 publications

(5 citation statements)

References 69 publications

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“…This foregrounds the consequences of differential van der Waals and electrostatic forces in structural behavior once intercalated into the bilayer . Therefore, it is reasonable to suggest that the arrangement of the phosphocholine and sulfobetaine headgroups will modulate structural and hydration behavior relative to POPC:O-Lyso-PC mesophases …”

Section: Resultssupporting

confidence: 80%

“…71 Therefore, it is reasonable to suggest that the arrangement of the phosphocholine and sulfobetaine headgroups will modulate structural and hydration behavior relative to POPC:O-Lyso-PC mesophases. 72 Second, we consider the hydrophobic chain tails. In our work, our experimental detergents have different tails: a C12:0 alkyl chain for DDAPS and a C18:1 (Δ 9 ) acyl tail for O-Lyso-PC, in comparison to POPC with a C18:1 (Δ 9 ) acyl tail and a C16:0 acyl tail.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Surfactant-Mediated Structural Modulations to Planar, Amphiphilic Multilamellar Stacks

et al. 2023

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The hydrophobic effect, a ubiquitous process in biology, is a primary thermodynamic driver of amphiphilic selfassembly. It leads to the formation of unique morphologies including two highly important classes of lamellar and micellar mesophases. The interactions between these two types of structures and their involved components have garnered significant interest because of their importance in key biochemical technologies related to the isolation, purification, and reconstitution of membrane proteins. This work investigates the structural organization of mixtures of the lamellar-forming phospholipid 1palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and two zwitterionic micelle-forming surfactants, being n-dodecyl-N,Ndimethyl-3-ammonio-1-propanesulfonate (Zwittergent 3-12 or DDAPS) and 1-oleoyl-2-hydroxy-sn-glycero-3-phosphocholine (O-Lyso-PC), when assembled by water vapor hydration with X-ray diffraction measurements, brightfield optical microscopy, wide-field fluorescence microscopy, and atomic force microscopy. The results reveal that multilamellar mesophases of these mixtures can be assembled across a wide range of POPC to surfactant (POPC:surfactant) concentration ratios, including ratios far surpassing the classical detergent-saturation limit of POPC bilayers without significant morphological disruptions to the lamellar motif. The mixed mesophases generally decreased in lamellar spacing (D) and headgroup-to-headgroup distance (D hh ) with a higher concentration of the doped surfactant, but trends in water layer thickness (D w ) between each bilayer in the stack are highly variable. Further structural characteristics including mesophase topography, bilayer thickness, and lamellar rupture force were revealed by atomic force microscopy (AFM), exhibiting homogeneous multilamellar stacks with no significant physical differences with changes in the surfactant concentration within the mesophases. Taken together, the outcomes present the assembly of unanticipated and highly unique mixed mesophases with varied structural trends from the involved surfactant and lipidic components. Modulations in their structural properties can be attributed to the surfactant's chemical specificity in relation to POPC, such as the headgroup hydration and the hydrophobic chain tail mismatch. Taken together, our results illustrate how specific chemical complexities of surfactant− lipid interactions can alter the morphologies of mixed mesophases and thereby alter the kinetic pathways by which surfactants dissolve lipid mesophases in bulk aqueous solutions.

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Section: Resultssupporting

confidence: 80%

Section: ■ Results and Discussionmentioning

confidence: 99%

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Surfactant-Mediated Structural Modulations to Planar, Amphiphilic Multilamellar Stacks

et al. 2023

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“…Although, the linearity stated by Eq. 4.23, is slightly disturbed, most probably due to admixture effects (Pfeiffer et al 2010), the parameters A and B are very similar to the original values published before. An important limitation of this method should be mentioned; the quadrupolar splitting is reduced at and in the range of the main phase transition, a phenomenon which is called motional narrowing (Bryant et al 1992).…”

Section: Nuclear Magnetic Resonance (Nmr): Quadrupolar Splitting and supporting

confidence: 78%

Hydration Forces Between Lipid Bilayers: A Theoretical Overview and a Look on Methods Exploring Dehydration

Pfeiffer

2015

Subcellular Biochemistry

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Although, many biological systems fulfil their functions under the condition of excess hydration, the behaviour of bound water as well as the processes accompanying dehydration are nevertheless important to investigate. Dehydration can be a result of applied mechanical pressure, lowered humidity or cryogenic conditions. The effort required to dehydrate a lipid membrane at relatively low degree of hydration can be described by a disjoining pressure which is called hydration pressure or hydration force. This force is short-ranging (a few nm) and is usually considered to be independent of other surface forces, such as ionic or undulation forces. Different theories were developed to explain hydration forces that are usually not consistent with each other and which are also partially in conflict with experimental or numerical data.Over the last decades it has been more and more realised that one experimental method alone is not capable of providing much new insight into the world of such hydration forces. Therefore, research requires the comparison of results obtained from the different methods. This chapter thus deals with an overview on the theory of hydration forces, ranging from polarisation theory to protrusion forces, and presents a selection of experimental techniques appropriate for their characterisation, such as X-ray diffraction, atomic force microscopy and even calorimetry.

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“…The effects of pressure and temperature are described by the compressibility and thermal expansivity coefficients (moduli), respectively (49). Hydration of lipids has been investigated extensively (29,70,71), whereby the number of waters per lipid can be controlled by gravimetrically varying the amount of water or addition of osmolyte, which removes water from the interbilayer region. When lipid bilayers are forced into close proximity, short-range repulsion is generated (30,72), including both hydration and steric components (27,31) due to bilayer undulations and/or protrusion forces (26).…”

Section: Water Plays a Key Role In Membrane Deformationmentioning

confidence: 99%

Solid-State 2H NMR Shows Equivalence of Dehydration and Osmotic Pressures in Lipid Membrane Deformation

Mallikarjunaiah

Leftin

Kinnun

et al. 2011

Biophysical Journal

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Lipid bilayers represent a fascinating class of biomaterials whose properties are altered by changes in pressure or temperature. Functions of cellular membranes can be affected by nonspecific lipid-protein interactions that depend on bilayer material properties. Here we address the changes in lipid bilayer structure induced by external pressure. Solid-state ²H NMR spectroscopy of phospholipid bilayers under osmotic stress allows structural fluctuations and deformation of membranes to be investigated. We highlight the results from NMR experiments utilizing pressure-based force techniques that control membrane structure and tension. Our ²H NMR results using both dehydration pressure (low water activity) and osmotic pressure (poly(ethylene glycol) as osmolyte) show that the segmental order parameters (S(CD)) of DMPC approach very large values of ≈ 0.35 in the liquid-crystalline state. The two stresses are thermodynamically equivalent, because the change in chemical potential when transferring water from the interlamellar space to the bulk water phase corresponds to the induced pressure. This theoretical equivalence is experimentally revealed by considering the solid-state ²H NMR spectrometer as a virtual osmometer. Moreover, we extend this approach to include the correspondence between osmotic pressure and hydrostatic pressure. Our results establish the magnitude of the pressures that lead to significant bilayer deformation including changes in area per lipid and volumetric bilayer thickness. We find that appreciable bilayer structural changes occur with osmotic pressures in the range of 10-100 atm or lower. This research demonstrates the applicability of solid-state ²H NMR spectroscopy together with bilayer stress techniques for investigating the mechanism of pressure sensitivity of membrane proteins.

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Thermodynamic and structural behaviour of equimolar POPC/CnE4 (n=8, 12, 16) mixtures by sorption gravimetry, 2H NMR spectroscopy and X-ray diffraction

Cited by 5 publications

References 69 publications

Surfactant-Mediated Structural Modulations to Planar, Amphiphilic Multilamellar Stacks

Surfactant-Mediated Structural Modulations to Planar, Amphiphilic Multilamellar Stacks

Hydration Forces Between Lipid Bilayers: A Theoretical Overview and a Look on Methods Exploring Dehydration

Solid-State 2H NMR Shows Equivalence of Dehydration and Osmotic Pressures in Lipid Membrane Deformation

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