Anion-Transport-Related Conformational Changes of the Band 3 Protein in the Red Blood Cell Membrane

Passow, Hermann

doi:10.1007/978-1-4684-4085-0_65

Cited by 8 publications

(3 citation statements)

References 42 publications

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“…The fact that the binding of NAP-taurine is strongly affected by the confor- mation of the transport site provides further evidence that the transport and NAP-taurine sites may be closely adjacent. It also suggests that the conformational change of the transport site affects other regions of the transport protein, a point that is reinforced by other evidence that changes in transport site conformation affect the interactions of various inhibitors with the system (Knauf and Mann, 1984b;Passow et al, 1980a, b;Passow, 1982).…”

Section: Intrinsic Asymmetry Of the Transport Systemmentioning

confidence: 85%

Effects of the transport site conformation on the binding of external NAP-taurine to the human erythrocyte anion exchange system. Evidence for intrinsic asymmetry.

Knauf¹,

Law²,

Tarshis³

et al. 1984

The Journal of General Physiology

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External N-(4-azido-2-nitrophenyl}2-aminoethylsulfonate (NAPtaurine) inhibits human red cell chloride exchange by binding to a site that is distinct from the chloride transport site. Increases in the intracellular chloride concentration (at constant external chloride) cause an increase in the inhibitory potency of external NAP-taurine. This effect is not due to the changes in pH or membrane potential that usually accompany a chloride gradient, since even when these changes are reversed or eliminated the inhibitory potency remains high . According to the ping-pong model for anion exchange, such transmembrane effects of intracellular chloride on external NAP-taurine can be explained if NAP-taurine only binds to its site when the transport site is in the outwardfacing (E. or ECIo) form . Since NAP-taurine prevents the conformational change from ECIo to ECli, it must lock the system in the outward-facing form . NAPtaurine can therefore be used just like the competitive inhibitor HQDIDS (4,4'-diisothiocyano-1,2-diphenylethane-2,2'-disulfonic acid) to monitor the fraction of transport sites that face outward. A quantitative analysis of the effects of chloride gradients on the inhibitory potency of NAP-taurine and H2DIDS reveals that the transport system is intrinsically asymmetric, such that when Cli = Cl., most of the unloaded transport sites face the cytoplasmic side of the membrane .

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Section: Intrinsic Asymmetry Of the Transport Systemmentioning

confidence: 85%

Effects of the transport site conformation on the binding of external NAP-taurine to the human erythrocyte anion exchange system. Evidence for intrinsic asymmetry.

Knauf¹,

Law²,

Tarshis³

et al. 1984

The Journal of General Physiology

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“…Anion transport across the red cell membrane appears to be associated with conformational changes of the Band 3 transport domain (Passow, 1982;Knauf et al, 1984;Jennings, 1985). (For review see Knauf, 1979;Macara & Cantley, 1983;Passow, 1985). Protons could be involved in substrate anion binding or they could modify the rate of translocation of Substrate anions across the erythrocyte membrane.…”

Section: Introductionmentioning

confidence: 98%

“…Subsequently, the substrate anion is translocated across the red cell membrane and, finally, it is released at the opposite membrane surface. Anion transport across the red cell membrane appears to be associated with conformational changes of the Band 3 transport domain (Passow, 1982;Knauf et al, 1984;Jennings, 1985). (For review see Knauf, 1979;Macara & Cantley, 1983;Passow, 1985).…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Band 3 substrate site in human red cell ghosts by NDS-TEMPO, a disulfonatostilbene spin probe: The function of protons in NDS-TEMPO and substrate-anion binding in relation to anion transport

1986

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NDS-TEMPO is a specific disulfonatostilbene spin label for the Band 3 substrate site (K.F. Schnell, W. Elbe, J. Käsbauer & E. Kaufmann, Biochim. Biophys. Acta 732:266-275, 1983). The pH dependence of NDS-TEMPO binding and of chloride and sulfate binding was studied in resealed human erythrocyte ghosts. pH was varied from 6.0 to 9.0. The ESR spectra from NDS-TEMPO-labeled red cell ghosts exhibited a strong immobilization of membrane-bound NDS-TEMPO. Changes of pH had no effect upon the mobility of membrane-bound NDS-TEMPO. A mutual competition between NDS-TEMPO binding and the binding of the substrate-anions, chloride and sulfate, was observed throughout the entire pH range. The maximal number of NDS-TEMPO binding sites per cell was in the range of 9.0 X 10(5) to 1.10 X 10(6) and was found to be insusceptible to changes of pH. The NDS-TEMPO/substrate-site and the chloride/substrate-site dissociation constants amounted to 1.25 microM and to 17 mM and were independent of pH from pH 6.0 to 8.0, while the sulfate/substrate-site dissociation constant displayed a strong pH dependency with a maximum of approximately 50 mM at about pH 7.0. The NDS-TEMPO inhibition constants from the chloride and the sulfate flux experiments were 0.5 microM (0 degree C) and 1.8 microM (25 degrees C), respectively, and are in close accordance with the NDS-TEMPO/substrate-site dissociation constants. Our studies provide strong evidence for the assumption that NDS-TEMPO binds in fact to the substrate site of Band 3. They show that the strong pH dependence of the chloride and of the sulfate transport cannot result from the pH dependency of substrate-anion binding, but point to the participation of ionizable regulator sites in transport catalysis. These regulator sites seem to be positioned outside the substrate site of the Band 3 transport domain.

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Binding of cytosolic proteins to the erythrocyte membrane

Salhany

1983

J of Cellular Biochemistry

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Certain enzymes and other proteins, traditionally thought to be exclusively cytosolic, have very often been found to be associated with isolated plasma membranes. These findings raise fundamental questions about concepts of membrane structure and the methods used to isolate membranes. It is conceivable that the interaction of cytosolic proteins is central to the overall structure and function of the cell in vivo. However, it is necessary to consider the specificity of the various interactions and evidence for their occurrence under conditions which can exist within the cell.The interaction of cytoplasmic proteins with the erythrocyte membrane has enjoyed renewed interest [ 11. Although earlier work considered the problem of the interaction of hemoglobin with the membrane [2-171, more recent studies have shown that certain glycolytic enzymes also bind to specific sites [7, and that a class of peripherally associated, so-called cytoskeletal, proteins exist [23-281. The interaction of hemoglobin and the glycolytic enzymes has been shown to be largely electrostatic in nature and the discussion of the physiologic significance of these interactions is accelerating.One might at first disregard the electrostatic association of hemoglobin and the glycolytic enzymes as simply an isolation artifact. However, closer examination has shown a surprising degree of specificity in binding even under the nonphysiologic conditions necessary to study binding stoichiometry. The site of high affinity binding has been shown to be band 3 protein, the integral membrane protein involved in C1-/ HC03-exchange [l]. In this paper, I shall attempt to critically summarize the later Abbreviations used: G3PD, glyceraldehyde-3P dehydrogenase; EPR, electron paramagnetic resonance; PFK, phosphofructokinase; DIDS, 4.4 -bis (isothiocyano)-

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Anion-Transport-Related Conformational Changes of the Band 3 Protein in the Red Blood Cell Membrane

Cited by 8 publications

References 42 publications

Effects of the transport site conformation on the binding of external NAP-taurine to the human erythrocyte anion exchange system. Evidence for intrinsic asymmetry.

Effects of the transport site conformation on the binding of external NAP-taurine to the human erythrocyte anion exchange system. Evidence for intrinsic asymmetry.

Characterization of the Band 3 substrate site in human red cell ghosts by NDS-TEMPO, a disulfonatostilbene spin probe: The function of protons in NDS-TEMPO and substrate-anion binding in relation to anion transport

Binding of cytosolic proteins to the erythrocyte membrane

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