PMID: 37904Jul 10, 1979

Effect of surface potential on the intramembrane electrical field measured with carotenoid spectral shift in chromatophores from Rhodopseudomonas sphaeroides

Biochimica Et Biophysica Acta
K MatsuuraM Nishimura

Abstract

Changes in the surface potential, the electrical potential difference between the membrane surface and the bulk aqueous phase were measured with the carotenoid spectral shift which indicates the change of electrical field in the membrane. Chromatophores were prepared from a non-sulfur purple bacterium, Rhodopseudomonas sphaeroides, in a low-salt buffer. Surface potential was changed by addition of salt or by pH jump as predicted by the Gouy-Chapman diffuse double layer theory. When a salf was added at neutral pH, the shift of carotenoid spectrum to shorter wavelength, corresponding to an increase in electrical potential at the outside surface, was observed. The salts of divalent cations (MgSO4, MgCl-2, CaCl2) were effective at concentrations lower than those of monovalent cation salts (NACl, KCl, Na2SO4) by a factor of about 50. Among the salts of monoor divalent cation used, little ionic species-dependent difference was observed in the low-concentration range except that due to the valence of cations. The pH dependence of the salt-induced carotenoid change was explained in terms of the change in surface charge density, which was about 0 at pH 5--5.5 and had negative values at higher pH values. The dependence of the pH jump-ind...Continue Reading

References

Nov 1, 1980·Quarterly Reviews of Biophysics·D Devault
May 1, 1983·Quarterly Reviews of Biophysics·S W Thorne, J T Duniec
Dec 17, 2014·Photosynthesis Research·André VerméglioFabrice Rappaport
Apr 21, 2006·Biochimica Et Biophysica Acta·Armen Y MulkidjanianDmitry A Cherepanov
Apr 14, 2017·Journal of Bioenergetics and Biomembranes·Jaromír PlášekMilan Hoefer

Related Concepts

Cations, Divalent
Carotenoids
Resting Potentials
Sulfur
Bacterial Chromatophore
Menopause
Chromatophore
Cations
Rhodobacter sphaeroides
Intracellular Membranes

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