INTERACTING PHOSPHOLIPID BILAYERS: Measured Forces and Induced Structural Changes

Rand, R. P.

doi:10.1146/annurev.bb.10.060181.001425

Cited by 482 publications

(242 citation statements)

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“…The ways in which we measure intermembrane or intermolecular forces are described elsewhere (6,7,15,24,25). A schematic picture of how we do it will suggest a way to connect these measurements to cellular processes.…”

Section: Methodsmentioning

confidence: 99%

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Water near intracellular surfaces.

Parsegian¹,

Rau²

1984

The Journal of Cell Biology

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In this paper we make the following points: Water is perturbed within several angstroms of the surfaces of soluble molecules. Removal of this water can require significant amounts of work, seen as an exponentially varying "hydration force" with respect to molecular separation. The favorable and specific attractions that occur in molecular assembly or in ligand binding imply that the specific association between the molecular surfaces is stronger than the association of those surfaces with water. The specificity of biochemical association is not simply a matter of protein-protein interaction but also of competing protein-water interactions. Small structural changes in molecular surfaces can evoke large changes in the contact energy of hydrated surfaces; surface hydration and the energetics of water displacement are a likely mechanism for the contact specificity of intracellular associations integrating the cell matrix.

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Section: Methodsmentioning

confidence: 99%

“…Controlled vapor pressure or direct pressure through a semipermeable membrane is also used (10,15,24) . be attractive.…”

Section: Water Near Intracellular Surfacesmentioning

confidence: 99%

Water near intracellular surfaces.

Parsegian¹,

Rau²

1984

The Journal of Cell Biology

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“…One of the major barriers inhibiting the fusion of two lipid bilayers is the layer of water between them creating a hydration repulsive pressure (74). Alcohol at the surface of the membrane can replace water thereby lowering the hydration repulsive pressure (75).…”

Section: Possible Mechanisms For Enhancement Of Fusion By Cis Additiomentioning

confidence: 99%

Drunken Membranes: Short-Chain Alcohols Alter Fusion of Liposomes to Planar Lipid Bilayers

Paxman

Hunt

Hallan

et al. 2017

Biophysical Journal

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Although the effects of ethanol on protein receptors and lipid membranes have been studied extensively, ethanol's effect on vesicles fusing to lipid bilayers is not known. To determine the effect of alcohols on fusion rates, we utilized the nystatin/ergosterol fusion assay to measure fusion of liposomes to a planar lipid bilayer (BLM). The addition of ethanol excited fusion when applied on the cis (vesicle) side, and inhibited fusion on the trans side. Other short-chain alcohols followed a similar pattern. In general, the inhibitory effect of alcohols (trans) occurs at lower doses than the excitatory (cis) effect, with a decrease of 29% in fusion rates at the legal driving limit of 0.08% (w/v) ethanol (IC 50 ¼ 0.2% v/v, 34 mM). Similar inhibitory effects were observed with methanol, propanol, and butanol, with ethanol being the most potent. Significant variability was observed with different alcohols when applied to the cis side. Ethanol and propanol enhanced fusion, butanol also enhanced fusion but was less potent, and low doses of methanol mildly inhibited fusion. The inhibition by trans addition of alcohols implies that they alter the planar membrane structure and thereby increase the activation energy required for fusion, likely through an increase in membrane fluidity. The cis data are likely a combination of the above effect and a proportionally greater lowering of the vesicle lysis tension and hydration repulsive pressure that combine to enhance fusion. Alternate hypotheses are also discussed. The inhibitory effect of ethanol on liposome-membrane fusion is large enough to provide a possible biophysical explanation of compromised neuronal behavior.

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“…The SFV E1 protein also contains a fusion peptide (Garoff et al, 1980a), and its involvement in fusion is supported by site-directed mutagenesis (Levy-Mintz and Kielian, 1991). Biophysically, the initiation of the fusion reaction mediated by viral spike proteins encompasses: (i) recognition of the appropriate target membrane; (ii) approach of the two membranes into molecular contact; and (iii) breakdown of the hydration barrier, which represents the major repulsive physical force between bilayers (Rand, 1981). The approach of the membranes into molecular contact is presumably realized by the insertion of the fusion peptide into the target membrane, providing a molecular bridge between two bilayers.…”

Section: Membrane Fusionmentioning

confidence: 99%