scholarly journals Anion transport inhibitor binding to band 3 in red blood cell membranes.

1983 ◽  
Vol 81 (3) ◽  
pp. 421-449 ◽  
Author(s):  
A S Verkman ◽  
J A Dix ◽  
A K Solomon
Keyword(s):  
Conformational Change ◽  
Temperature Jump ◽  
Band 3 ◽  
Anion Transport ◽  
Stopped Flow ◽  
Binding Studies ◽  
Binding Model ◽  
High Affinity ◽  
Sequential Binding ◽  
Red Blood Cell Membranes

The inhibitor of anion exchange 4,4'-dibenzoamido-2,2'-disulfonic stilbene (DBDS) binds to band 3, the anion transport protein in human red cell ghost membranes, and undergoes a large increase in fluorescence intensity when bound to band 3. Equilibrium binding studies performed in the absence of transportable anions show that DBDS binds to both a class of high-affinity (65 nM) and low-affinity (820 nM) sites with stoichiometry equivalent to 1.6 nmol/mg ghost protein for each site, which is consistent with one DBDS site on each band 3 monomer. The kinetics of DBDS binding were studied both by stopped-flow and temperature-jump experiments. The stopped-flow data indicate that DBDS binding to the apparent high-affinity site involves association with a low-affinity site (3 microM) followed by a slow (4 s-1) conformational change that locks the DBDS molecule in place. A detailed, quantitative fit of the temperature-jump data to several binding mechanisms supports a sequential-binding model, in which a first DBDS molecule binds to one monomer and induces a conformational change. A second DBDS molecule then binds to the second monomer. If the two monomers are assumed to be initially identical, thermodynamic characterization of the binding sites shows that the conformational change induces an interaction between the two monomers that modifies the characteristics of the second DBDS binding site.

Further Studies on Zn2+-Mediated Domain–Domain Communication in Human Erythrocyte Band 3

1998 ◽  
Vol 18 (5) ◽  
pp. 265-277
Author(s):  
Hong Xu ◽  
Xujia Zhang ◽  
Fu Yu Yang
Keyword(s):  
Conformational Change ◽  
Human Erythrocyte ◽  
Cytoplasmic Domain ◽  
Band 3 ◽  
Anion Transport ◽  
Intrinsic Fluorescence ◽  
Transport Activity ◽  
Membrane Domain ◽  
Nmr Study ◽  
Anion Transport Activity

Human erythrocyte band 3 is purified and reconstituted into vesicles, forming right-side-out proteoliposomes. Zn2+ entrapped inside the proteoliposomes inhibits the anion transport activity of band 3, and removal of the cytoplasmic domain of band 3 is able to diminish Zn2+ inhibition. Thus, the inhibition of activity of band 3 results from the Zn2+ induced conformational change of the cytoplasmic domain, which in turn is transmitted to the membrane domain. The results of intrinsic fluorescence and its quenching by HB and the 35Cl NMR study indicate that the cytoplasmic domain is essential for the conformational change induced by Zn2+.SH-blocking reagents, CH3I and GSSG, are used to modify the cytoplasmic domain, where they specifically bind to Cys201 and Cys317. It is observed that the Zn2+ induced inhibition of anion transport activity is blocked. This demonstrates that Cys201 and Cys317 are required in Zn2+-mediated domain–domain communication.

n-Alkanols and halothane inhibit red cell anion transport and increase band 3 conformational change rate

Biochemistry ◽  
1985 ◽  
Vol 24 (18) ◽  
pp. 4859-4866 ◽  
Author(s):  
Stuart A. Forman ◽  
A. S. Verkman ◽  
James A. Dix ◽  
A. K. Solomon
Keyword(s):  
Conformational Change ◽  
Band 3 ◽  
Anion Transport ◽  
Red Cell ◽  
Change Rate

scholarly journals Architecture of Allosteric Structure. Equation of State Containing Three Unknown Quantities for Fractional Saturation of whole Human Blood with O2: Formatting the Adair Equation to Accommodate Ordered Equivalent Sequences of O2-Binding Reactions and a Single Conformation Change Not Concerted with O2 Binding

2019 ◽  
Author(s):  
Francis Knowles ◽  
Douglas Magde
Keyword(s):  
Equation Of State ◽  
Equilibrium Constant ◽  
Oxygen Affinity ◽  
Conformation Change ◽  
Binding Model ◽  
High Affinity ◽  
Binding Data ◽  
Sequential Binding ◽  
Cell Acid ◽  
O2 Binding

<p>O<sub>2</sub>-Equilibrium binding data of hemoglobin in whole blood under standard conditions (Kernohan JC. & Roughton FJW (1972) in Oxygen Affinity of Hemoglobin and Red Cell Acid Base Status, ed Rorth and Astrup, Copenhagen, Munksgaard, pp 65-72; Severinghaus JW in <i>ibid</i> pp. xx-xx) was fitted to an equation of state comprised of three unknown quantities: <i>K</i>α, the equilibrium constant for binding O<sub>2</sub> by equivalent low affinity α-chains;<i> K<sub>ΔC</sub></i>, a dimensionless equilibrium constant describing the conformation change between low- and high-affinity conformations of hemoglobin, <sup>T</sup>state and <sup>R</sup>state; <i>K</i><sub>β</sub>, the equilibrium constant for binding O<sub>2</sub> by equivalent high affinity β-chains, the Perutz/Adair Equation. Values of the unknown quantities at pH 7.4 and 37<sup>o</sup>C are: <i>K</i><sub>α </sub>= 15,090 L/mol; <i>K<sub>ΔC</sub></i> = 0.0260; <i>K</i><sub>β</sub> = 393,900 L/mol. </p> <p> </p> <p>A graph of predicted <i>versus</i> observed values of fractional saturation, <i>F</i>, is linear: <i>F</i><sub>PRE</sub> = 0.9998 <i>F</i><sub>OBS</sub> – 0.0005, r<sup>2</sup> =0.9997. The Perutz/Adair equation of state is defined as such insofar as all aspects of the stereochemical model (Perutz MF (1970) Nature London 228, 726-739) are imposed on the earlier sequential binding model of Adair (1925) JBC 63, 493-545.</p> <br>

Architecture of Allosteric Structure. Equation of State Containing Three Unknown Quantities for Fractional Saturation of whole Human Blood with O2: Formatting the Adair Equation to Accommodate Ordered Equivalent Sequences of O2-Binding Reactions and a Single Conformation Change Not Concerted with O2 Binding

2019 ◽  
Author(s):  
Francis Knowles ◽  
Douglas Magde
Keyword(s):  
Equation Of State ◽  
Equilibrium Constant ◽  
Oxygen Affinity ◽  
Conformation Change ◽  
Binding Model ◽  
High Affinity ◽  
Binding Data ◽  
Sequential Binding ◽  
Cell Acid ◽  
O2 Binding

<p>O<sub>2</sub>-Equilibrium binding data of hemoglobin in whole blood under standard conditions (Kernohan JC. & Roughton FJW (1972) in Oxygen Affinity of Hemoglobin and Red Cell Acid Base Status, ed Rorth and Astrup, Copenhagen, Munksgaard, pp 65-72; Severinghaus JW in <i>ibid</i> pp. xx-xx) was fitted to an equation of state comprised of three unknown quantities: <i>K</i>α, the equilibrium constant for binding O<sub>2</sub> by equivalent low affinity α-chains;<i> K<sub>ΔC</sub></i>, a dimensionless equilibrium constant describing the conformation change between low- and high-affinity conformations of hemoglobin, <sup>T</sup>state and <sup>R</sup>state; <i>K</i><sub>β</sub>, the equilibrium constant for binding O<sub>2</sub> by equivalent high affinity β-chains, the Perutz/Adair Equation. Values of the unknown quantities at pH 7.4 and 37<sup>o</sup>C are: <i>K</i><sub>α </sub>= 15,090 L/mol; <i>K<sub>ΔC</sub></i> = 0.0260; <i>K</i><sub>β</sub> = 393,900 L/mol. </p> <p> </p> <p>A graph of predicted <i>versus</i> observed values of fractional saturation, <i>F</i>, is linear: <i>F</i><sub>PRE</sub> = 0.9998 <i>F</i><sub>OBS</sub> – 0.0005, r<sup>2</sup> =0.9997. The Perutz/Adair equation of state is defined as such insofar as all aspects of the stereochemical model (Perutz MF (1970) Nature London 228, 726-739) are imposed on the earlier sequential binding model of Adair (1925) JBC 63, 493-545.</p> <br>

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