Electrostatic Interactions in Membranes and Proteins

Honig, Barry; Hubbell, Wayne L.; Flewelling, R.F.

doi:10.1146/annurev.bb.15.060186.001115

Cited by 415 publications

(295 citation statements)

References 5 publications

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“…The time constant for MG transport would be longest for Cl -, next longest for Br -, and shortest for the organic anions. The energy barrier for moving MG from the aqueous bulk electrolyte solution to the inside of the hydrophobic bilayer using a Born energy model is described in detail in ref 40. Figure 6 schematically illustrates how different anion species affect the energy barrier for MG in going from an aqueous electrolyte bulk solution to the interior of the bilayer.…”

Section: Resultsmentioning

confidence: 99%

Effects of Counterions on Molecular Transport Across Liposome Bilayer: Probed by Second Harmonic Generation

et al. 2001

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The transport rate of an organic cation, malachite green (MG), across a unilamellar bilayer (∼105 nm) of the dioleoylphosphatidylglycerol (DOPG) liposome has been studied by the SHG technique. This is the first time to our knowledge that the effects of anions on molecular cation transport have been observed. Our studies show four results. First, in the presence of sodium chloride (NaCl) or sodium bromide (NaBr), the time constant for transport of MG across the DOPG bilayer increases with the increase in the concentration of the counterion (i.e., Cl -or Br -). Second, with the organic electrolytes, sodium citrate (NaCitrate) and sodium ethanesulfonate (NaEtSO 3 ), the transport rate is independent of the concentration of the counterion (i.e., Citrateand EtSO 3 -). Third, at the same counterion concentration, the transport rate depends on the species of the counterion used. The rate of MG transport is the slowest with Cl -, faster with Br -, and the fastest with the two organic counterions, Citrate -and EtSO 3 -. Last, at the low counterion concentration of 1mM, the transport rates of MG were found to approach the same value for the four anions. A brief discussion of a possible mechanism is presented.

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Section: Resultsmentioning

confidence: 99%

Effects of Counterions on Molecular Transport Across Liposome Bilayer: Probed by Second Harmonic Generation

et al. 2001

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“…One mechanism by which the internal potential [22] of BR could be significantly altered is by changes in net charge on the cytoplasmic and extracellular surfaces. On the basis of the predicted 2-dimensional topology of BR [23], the net charge at pH 7 is expected to be -3 on the cytoplasmic side and -2 on the extracellular side, thus producing an electrostatic field in the same direction as the normal transmembrane field (i.e.…”

Section: Resultsmentioning

confidence: 99%

Bacteriorhodopsin's M₄₁₂ and BR₆₀₅ protein conformations are similar Significance for proton transport

Marrero

Rothschild

1987

FEBS Letters

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Cation removal or acidification induces a transition of bacteriorhodopsin (BR& to a blue species (BR&. Fourier transform infrared spectroscopy now reveals that the protein conformational changes accompanying this transition resemble those which occur during the BR 568 to M412 transition and associated light-driven proton transport. This and other results suggest that Bbs and M ,,I2 both have similar voltage-dependent protein conformations in which a secondary structure is stabilized by a change in the local electric potential sensed by internal charged groups involved in proton transport.

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“…Neutral energy is the free energy change in moving 1 mol of lipophilic ions from the water to membrane phase, excluding the electrical contribution. Dipole energy results from the selective orientation of phospholipid head groups, phospholipid carbonyls and surface-water molecules with the charged amphiphile [22][23][24].…”

Section: Discussionmentioning

confidence: 99%

“…The membrane dipole potential calculated from the membrane-water partition coefficients was approximately 25 mV lower in membranes comprised of PlasCho than in membranes comprised of PhosCho or AlkCho (Table 2). This substantial difference in dipole potential in membrane bilayers comprised of different phospholipid subclasses can be explained by both the differential membrane conformation and the covalent structure of each phospholipid subclass near the membrane interface including : (i) the presence of an induced dipole in the double bond of the vinyl ether linkage of plasmalogens [8,9] ; (ii) the differences in both the conformation and dynamics of the phospholipid head groups in choline glycerophospholipid subclasses [32,33] ; and (iii) the alterations in the orientation of the carbonyl group at the sn-2 fatty acid chains [22][23][24]. It should be noted that previous workers have assumed that the sn-1 acyl chain in diacyl phospholipids does not contribute substantially to the membrane dipole potential since the dipole of carbonyl is oriented perpendicularly to the membrane director [24,34,35].…”

Section: Table 2 Determination Of the Relative Dipole Potential In Mementioning

confidence: 99%

Phospholipid-subclass-specific partitioning of lipophilic ions in membrane–water systems

Zeng

Han

Gross

1999

Biochemical Journal

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Herein, we systematically investigate phospholipid-subclassspecific alterations in the partitioning of both cationic and anionic amphiphiles to identify the importance of ester, ether and vinyl ether linkages at the sn-1 position of phospholipids in the partitioning of charged amphiphiles. The results demonstrated that the membrane-water partition coefficient of a prototypic cationic amphiphile (i.e. 3,3h-dipropylthiadicarbocyanine iodide) was approximately 2.5 times higher in membranes comprised of plasmenylcholine in comparison with membranes comprised of either phosphatidylcholine or plasmanylcholine. In striking contrast, the membrane-water partition coefficient of a prototypic anionic amphiphile [i.e. bis-(1,3-dibutylbarbituric acid)trimethine oxonol] in membranes comprised of plasmenylcholine was $ 2.5 times lower than that manifest in membranes comprised of phosphatidylcholine or plasmanylcholine. Utilizing these experimentally determined partition coefficients, the relative membrane dipole potential of membranes comprised of

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Electrostatic Interactions in Membranes and Proteins

Cited by 415 publications

References 5 publications

Effects of Counterions on Molecular Transport Across Liposome Bilayer: Probed by Second Harmonic Generation

Effects of Counterions on Molecular Transport Across Liposome Bilayer: Probed by Second Harmonic Generation

Bacteriorhodopsin's M₄₁₂ and BR₆₀₅ protein conformations are similar Significance for proton transport

Phospholipid-subclass-specific partitioning of lipophilic ions in membrane–water systems

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Electrostatic Interactions in Membranes and Proteins

Cited by 415 publications

References 5 publications

Effects of Counterions on Molecular Transport Across Liposome Bilayer: Probed by Second Harmonic Generation

Effects of Counterions on Molecular Transport Across Liposome Bilayer: Probed by Second Harmonic Generation

Bacteriorhodopsin's M412 and BR605 protein conformations are similar Significance for proton transport

Phospholipid-subclass-specific partitioning of lipophilic ions in membrane–water systems

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Bacteriorhodopsin's M₄₁₂ and BR₆₀₅ protein conformations are similar Significance for proton transport