2 edition of dipole potential in monolayers, biolayers and biological membranes. found in the catalog.
dipole potential in monolayers, biolayers and biological membranes.
Walter Henry Dorn
Written in English
|The Physical Object|
|Number of Pages||148|
The phloretin-induced reduction in the dipole potential of planar lipid bilayers containing cholesterol, ergosterol, stigmasterol, 7-dehydrocholesterol and 5α-androstan-3β-ol was investigated. It is shown that effects depend on the type and concentration of membrane sterol. It is supposed that the effectiveness of phloretin in reducing the dipole potential of the bilayers that contain Cited by: 8. INTRODUCTION. Biological membranes create a complex and highly anisotropic electrostatic environment that supports biological function. Electrostatic interactions in and near the membrane are typically characterized by three potentials, illustrated in Fig. 1 transmembrane potential (ψ tr) is the well-known driving force for ion transport through channels in cell membranes, Cited by:
When combined with traditional electrokinetic measurements in liposome suspension and Volta potential control at lipid monolayers it reveals alterations of the dipole potential induced by multivalent cations (Be 2+, Gd 3+) about mV. It is related to the lipid phase transition detected by isotherm titration calorimetry (ITC) measurements. Internal Electrostatic Potentials in Bilayers: MeasuringandControlling Dipole Potentials in Lipid Vesicles are typically onthe orderofafewtens ofmVin biological membranes; nonetheless, they appear to have an important The magnitude of the dipole potential suggests that it shouldbeimportantin anumberofprocesses. Forexample.
The physical properties of lipid bilayers are sensitive to the specific type and composition of the lipids that make up the many different types of cell membranes. Studying model bilayers of representative heterogeneous compositions can provide key insights into membrane functionality. In this work, we use atomistic molecular dynamics simulations to characterize key properties in a number of Cited by: 1. Phloretin, a molecule which is known to decrease the dipole potential of lipid membranes, has a little effect on the CO frequencies of dimyristoylphosphatidylcholine bilayers (DMPC) in comparison to that observed on the phosphates. In the first case, the frequency is displaced very slightly to higher values, while a pronounced downward shift is observed on the asymmetric vibration frequencies Cited by:
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Journals & Books; Register Sign in. VolumeIssue 3, MarchPages Dipole potential as a driving force for the membrane insertion of polyacrylic acid in slightly acidic milieu.
A novel procedure for the measurement of the absolute value of the surface dipole potential χ of self-assembled lipid monolayers, which makes use of a phospholipid monolayer supported on mercury, is described.
It consists of increasing the tilt angle of the lipid molecules with respect to the monolayer normal by expanding progressively the supporting mercury drop and in measuring the charge Cited by: The membrane dipole potential (DP) manifests at the lipid–water interface.
It is dependent neither on the charge of the lipid nor on the ionic strength of the surrounding solution. This feature allows to distinguish between the DP and the surface potential (SP).Cited by: 4. Phloretin is known to adsorb to lipid surfaces and alters the dipole potential of lipid monolayers and bilayers.
Dipole potential in monolayers adsorption to biological and artificial membranes results in a change of the membrane permeability for a variety of charged and neutral compounds.
In this respect dipole potential in monolayers represents a model substance to study the effect of dipole potentials on membrane by: The dipole potentials of monolayers and bilayers should be the same when normalized for lipid packing density. However, they are not.
It has been discussed in several investigations that, e.g., a lipid packing-independent component of dipole potential measured in monolayers is Cited by: Indeed, such a model provides better agreement between experimental and computed dipole potentials, both for lipid monolayersand bilayers.
This combination of recently developed. Abstract. Of the individual potentials which comprise the potential profile of a membrane, the least well understood is the dipole potential.
In general, the dipole potential is manifested between the hydrocarbon interior of the membrane and the first few water layers adjacent to the lipid head by: The dipole potential is an electrical potential within phospholipid membranes, which arises because of the alignment of dipolar residues of the lipids and/or water dipoles in the region between.
This means that the dipole potentials of monolayers are higher than those of bilayers, and we used for our calculation again the maximum phloretin-induced potential change as a measure for the dipole potential of PC and PE membranes.
The adsorption of dipole molecules changes the dipole potential of monolayers and bilayersCited by: The effect of channel-forming peptide gramicidin A on the dipole potential of phospholipid monolayers and bilayers has been studied.
Surface pressure and surface potential isotherms of monolayers. Phloretin is known to adsorb to lipid surfaces and alters the dipole potential of lipid monolayers and bilayers.
Its adsorption to biological and artificial membranes results in a change of the membrane permeability for a variety of charged and neutral by: The effect of phloretin on the potential of phosphatidylcholine (PC), phosphatidylethanolamine (PE,) and phosphatidylglycerol (PG) monolayers below and above the phase transition in mixtures of different PC/PE ratios with and without cholesterol of ester and ether phospholipids have been determined.
The effectiveness of phloretin to decrease the dipole potential of monolayers Cited by: The influence of agents, known to affect the membrane dipole potential, phloretin and RHon the multi channel activity of amphotericin B in lipid bilayers of various compositions, was studied.
We present here an alternative theoretical treatment that takes into account the strong interaction between membrane (monolayer) dipole field and the dipole moment of the adsorbed molecule.
This treatment provides a much better fit of the experimental results derived from the measurements of surface potentials of lipid monolayers in the presence of by: The mechanisms underlying the influence of the membrane dipole potential on ion channel activity, including dipole-dipole and charge-dipole interactions in the pores and in membranes.
Abstract. The membrane dipole potential, ψ d, is an electrical potential difference with a value typically in the range – mV (positive in the membrane interior) which is located in the lipid headgroup region of the membrane, between the linkage of the hydrocarbon chains to the phospholipid glycerol backbone and the adjacent aqueous : Ronald J.
Clarke. WE report here detection of two kinds of asymmetry in planar lipid bilayers which may bear on the problem of asymmetry in biological membranes. One kind of asymmetry arises as a consequence of an. The nature and magnitude of the surface dipole potential χ at a membrane/water interface still remain open to discussion.
By combining measurements of differential capacity C and charge density σ at the interface between self-assembled monolayers of phosphatidylserine and phosphatidic acid supported by mercury and aqueous electrolytes of different concentration and pH, a sigmoidal dependence Cited by: The electrostatic properties of biological membranes can be described by three parameters: the transmembrane potential, the membrane surface potential, and the membrane dipole potential.
The first two are well characterized in terms of their magnitudes and biological effects. The dipole potential, however, is not well characterized. Various methods to measure the membrane dipole potential Cited by: Phloretin and its analogs adsorb to the surfaces of lipid monolayers and bilayers and decrease the dipole potential.
This reduces the conductance for anions and increases that for cations on artificial and biological membranes. The relationship between. lipids turns out to be coupled to the intrinsic membrane potential.
Dipole potential measurements of asymmetric membranes with leaflets composed of bacterial PE and 1,3-diolein (two lipids with different polar (neutral) head groups) revealed a nonzero intrinsic membrane potential.7 Recent .Interactions between signal (leader) sequences and membranes are critical to protein insertion and translocation across membranes.
In this paper, circular dichroism, tryptophan fluorescence, electrophoretic mobility, dipole potential, and binding measurements were used to study the interaction of the signal sequence of the Escherichia coli LamB protein with various lipid bilayers. By modifying.Fig. 1. The dependence of change in the membrane dipole potential (Δφd) onconcentration of thyroxine (A) and RH (B) in the bathing solution.
Membranes were made formed of DPhPC*,@ (), DOPC (), DOPS(♦), DOPE (Δ), Xanthene dyes.