New approaches for the reconstitution and functional assay of membrane transport proteins. Application to the anion transporter of human erythrocytes

Darmon, Audrey; Zangvill, M; Cabantchik, Z. I.

doi:10.1016/0005-2736(83)90371-1

Cited by 24 publications

(10 citation statements)

References 35 publications

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“…As resealed ghosts are fully active in water transport (Brahm, 1982), this indicates that peripheral proteins are not involved in the process as they are removed in the procedure used for the preparation of resealed ghosts (Darmon et al, 1983) but not in the preparation of purified erythrocyte membranes (Fairbanks et al, 1971). In contrast to the report by Macey (1984), we have not observed in this or previous studies that PCMBS inhibition of water diffusional permeability in erythrocytes can be reversed by saline washes.…”

Section: Discussioncontrasting

confidence: 58%

P-(Chloromercuri)benzenesulfonate binding by membrane proteins and the inhibition of water transport in human erythrocytes

Benga¹,

Popescu²,

Pop³

et al. 1986

Biochemistry

132

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The binding of [203Hg]-p-(chloromercuri)benzenesulfonate to the membrane proteins of human erythrocytes and erythrocyte ghosts was examined under conditions where binding to the bulk of membrane sulfhydryl groups was blocked by N-ethylmaleimide. Binding was essentially complete within 90 min when approximately 40 nmol was bound per milligram of membrane protein. This binding was correlated with the inhibition of water transport measured by an NMR technique. Maximal inhibition was observed with the binding of approximately 10 nmol of p-(chloromercuri)benzenesulfonate/mg of membrane protein. Under these conditions, both band 3 and band 4.5 bound 1 mol of inhibitor/mol of protein. In contrast to previous experiments, these results indicate that band 4.5 proteins as well as band 3 have to be considered as playing a role in water transport.

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Section: Discussioncontrasting

confidence: 58%

P-(Chloromercuri)benzenesulfonate binding by membrane proteins and the inhibition of water transport in human erythrocytes

Benga¹,

Popescu²,

Pop³

et al. 1986

Biochemistry

132

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“…The common approach to investigate this in model systems, like lipid vesicles, is to study the magnitude of sulfate permeability of the vesicles and its sensitivity to anion transport-specific inhibitors like DIDS or DNDS [2][3][4][5]7,8]. However, in the band 3-erythrocyte lipid vesicles we could not demonstrate any inhibiting effect of 10 k~M DIDS on the SO42 permeability, whereas similar concentrations of DIDS inhibited the SO42-transport of erythrocytes completely (data not shown).…”

Section: Specific Permeability Properties Of Erythrocyte Lipidband 3 mentioning

confidence: 87%

“…1) is an attractive candidate for studying protein-lipid interactions in model toluene-phosphatidylcholine extraction [3], adsorption to Bio-Beads [2,[4][5][6] or after replacement of Triton X-100 by N-octylglycoside, by dialysis [7]. It has been reported that by the use of the Triton X-100-Bio-Bead method, band 3 was successfully reconstituted into lipid vesicles [2,[4][5][6].…”

Section: Introductionmentioning

confidence: 99%

The influence of lipid composition on the barrier properties of band 3-containing lipid vesicles

Hoogevest

Maine

Kruijff

et al. 1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Band 3 protein has been incorporated into lipid vesicles consisting of 94:6 (molar ratio) egg phosphatidylcholine-bovine heart phosphatidylserine or total erythrocyte lipids by means of a Triton X-100 Bio-Beads method, with an additional sonication step prior to the removal of the detergent. This method results, for both types of band 3 lipid vesicles, in rather homogeneous vesicles with comparable protein content and vesicle trap. Freeze-fracture electron microscopy revealed that band 3-egg phosphatidylcholine-bovine heart phosphatidylserine vesicles have considerably more intramembrane particles as compared to the band 3-erythrocyte lipid vesicles. The dimensions of the nonspecific permeation pathways present in the band 3-lipid vesicles were measured using an influx assay procedure for nonelectrolytes of different size, in which the vesicles were sampled and subsequently freed from nonenclosed labeled permeant by means of gel-filtration. The band 3-egg phosphatidylcholine-bovine heart phosphatidylserine vesicles have nonspecific permeation pathways (pores), with diameters of up to 60 ~,. In contrast, the band 3-total erythrocyte lipid vesicles are more homogeneous and show much smaller nonspecific permeation pathways, having a diameter of about 12 ji,. These results suggest that the nonspecific permeability of the band 3-lipid vesicles is strongly lipid-dependent. Increase in specific anion permeability expected as a consequence of the presence of band 3 in the erythrocyte lipid vesicles was found to be very limited. However, stereospecific, phioretin-inhibitable D-glucose permeability could clearly be demonstrated in these vesicles. The difference of the nonspecific permeability of the band 3-egg phosphatidylcholine-bovine heart phosphatidylserine vesicles and band 3-erythrocyte lipid vesicles, is discussed in the light of the presence of defects at the lipid/protein interface and protein aggregation, which may induce formation of pores.

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“…Bicarbonate enters and exits red blood cells through a 95-kDa anion exchange protein (AEP), which passively exchanges Cl" for HCO 3 " (Cabantchik, 1991). This transporter is the most abundant protein in the red blood cell membrane (Darmon et al, 1983). As the erythrocyte passes through the tissue capillaries, bicarbonate exits the cell by facilitated diffusion and enters the interstitial fluid.…”

Section: The Role Of Bicarbonate In Proton Removalmentioning

confidence: 99%

Molecular Mechanisms of Dental Enamel Formation

Simmer

Fincham

1995

Critical Reviews in Oral Biology & Medicine

419

406

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Tooth enamel is a unique mineralized tissue in that it is acellular, is more highly mineralized, and is comprised of individual crystallites that are larger and more oriented than other mineralized tissues. Dental enamel forms by matrix-mediated biomineralization. Enamel crystallites precipitate from a supersaturated solution within a well-delineated biological compartment. Mature enamel crystallites are comprised of non-stoichiometric carbonated calcium hydroxyapatite. The earliest crystallites appear suddenly at the dentino-enamel junction (DEJ) as rapidly growing thin ribbons. The shape and growth patterns of these crystallites can be interpreted as evidence for a precursor phase of octacalcium phosphate (OCP). An OCP crystal displays on its (100) face a surface that may act as a template for hydroxyapatite (OHAp) precipitation. Octacalcium phosphate is less stable than hydroxyapatite and can hydrolyze to OHAp. During this process, one unit cell of octacalcium phosphate is converted into two unit cells of hydroxyapatite. During the precipitation of the mineral phase, the degree of saturation of the enamel fluid is regulated. Proteins in the enamel matrix may buffer calcium and hydrogen ion concentrations as a strategy to preclude the precipitation of competing calcium phosphate solid phases. Tuftelin is an acidic enamel protein that concentrates at the DEJ and may participate in the nucleation of enamel crystals. Other enamel proteins may regulate crystal habit by binding to specific faces of the mineral and inhibiting growth. Structural analyses of recombinant amelogenin are consistent with a functional role in establishing and maintaining the spacing between enamel crystallites.

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New approaches for the reconstitution and functional assay of membrane transport proteins. Application to the anion transporter of human erythrocytes

Cited by 24 publications

References 35 publications

P-(Chloromercuri)benzenesulfonate binding by membrane proteins and the inhibition of water transport in human erythrocytes

P-(Chloromercuri)benzenesulfonate binding by membrane proteins and the inhibition of water transport in human erythrocytes

The influence of lipid composition on the barrier properties of band 3-containing lipid vesicles

Molecular Mechanisms of Dental Enamel Formation

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