Characterization of 9-aminoacridine interaction with chromatophore membranes and modelling of the probe response to artificially induced transmembrane ΔpH values
| Autor: | Rita Casadio, Piero Fariselli, Bruno Andrea Melandri, Salvatore Di Bernardo |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Microdialysis
Biophysics Analytical chemistry Transmembrane pH difference Biochemistry Fluorescent probe chemistry.chemical_compound Probe-membrane interaction Bacterial chromatophore 9-Aminoacridine Phase (matter) Chromatophores Adsorption isotherm Fluorescent Dyes Tricine Quenching (fluorescence) Chemistry Vesicle Cell Membrane Charge density Cell Biology Hydrogen-Ion Concentration Fluorescence Aminacrine Membrane |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 1237:23-30 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(95)00075-e |
| Popis: | We analyze the adsorption of the fluorescent monoamine 9-aminoacridine to the membrane phase of photosynthetic chromatophores, in the physiological interval of pH values ranging from 5.5 to 8.5 and at ionic strengths of 0.005 and 0.150 M. The interaction of the probe with the membrane phase is described with S-shaped isotherms of the Hill type and is modulated by electrostatic effects as modelled with the Gouy-Chapman-Boltzman theory. This description is consistent with different values of the surface charge density of the chromatophore membranes decreasing from about 1.3 · 10dash3 to about 0.5 · 10 −3 e−/ A 2 , on changing the pH from 8.5/7.5 to 6.5/5.5, respectively. Furthermore we show that, when the free concentrations of the probe in the inner and outer vesicle compartments are computed from the adsorbing isotherms at the proper pH values, the model considering the equilibrium distribution of the neutral monoamine following the onset of a ΔpH is sufficient to describe the dependence of the artificially induced transmembrane ΔpH values on the observed quenching of the probe fluorescence. |
| Databáze: | OpenAIRE |
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