The proton motive force in isolated membrane vesicles and chromatophores from Rhodopseudomonas sphaeroides

1978 ◽  
Vol 44 (1) ◽  
pp. 115-115
Author(s):  
P. A. M. Michels ◽  
W. N. Konings
Keyword(s):  
Membrane Vesicles ◽  
Proton Motive Force ◽  
Motive Force ◽  
Rhodopseudomonas Sphaeroides ◽  
Isolated Membrane Vesicles

scholarly journals The Role of the Proton-Motive Force and Electron Flow in Light-Driven Solute Transport in Rhodopseudomonas sphaeroides

2005 ◽  
Vol 129 (3) ◽  
pp. 583-587 ◽  
Author(s):  
Marieke G. L. ELFERINK ◽  
Ilan FRIEDBERG ◽  
Klaas J. HELLINGWERF ◽  
Wil N. KONINGS
Keyword(s):  
Solute Transport ◽  
Electron Flow ◽  
Proton Motive Force ◽  
Motive Force ◽  
Rhodopseudomonas Sphaeroides

scholarly journals Mechanism of glucose and maltose transport in plasma-membrane vesicles from the yeast Candida utilis

1997 ◽  
Vol 321 (2) ◽  
pp. 487-495 ◽  
Author(s):  
Peter J. A. van den BROEK ◽  
Angeline E. van GOMPEL ◽  
Marijke A. H. LUTTIK ◽  
Jack T. PRONK ◽  
Carla C. M. van LEEUWEN
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Plasma Membranes ◽  
Membrane Vesicles ◽  
Proton Motive Force ◽  
Motive Force ◽  
Transport Systems ◽  
Sugar Accumulation ◽  
Plasma Membrane Vesicles ◽  
Maltose Transport

Transport of glucose and maltose was studied in plasma-membrane vesicles from Candida utilis. The yeast was grown on a mixture of glucose and maltose in aerobic carbon-limited continuous cultures which enabled transport to be studied for both sugars with the same vesicles. Vesicles were prepared by fusion of isolated plasma membranes with proteoliposomes containing bovine heart cytochrome coxidase as a proton-motive-force-generating system. Addition of reduced cytochrome cgenerated a proton-motive force, consisting of a membrane potential, negative inside, and a pH gradient, alkaline inside. Energization led to accumulation of glucose and maltose in these vesicles, reaching accumulation ratios of about 40Ő50. Accumulation also occurred in the presence of valinomycin or nigericin, but was prevented by a combination of the two ionophores or by uncoupler, showing that glucose and maltose transport are dependent on the proton-motive force. Comparison of sugar accumulation with quantitative data on the proton-motive force indicated a 1:1 H+/sugar stoichiometry for both transport systems. Efflux of accumulated glucose was observed on dissipation of the proton-motive force. Exchange and counterflow experiments confirmed the reversible character of the H+Őglucose symporter. In contrast, uncoupler or a mixture of valinomycin plus nigericin induced only a slow efflux of accumulated maltose. Moreover under counterflow conditions, the expected transient accumulation was small. Thus the H+Őmaltose symporter has some characteristics of a carrier that is not readily reversible. It is concluded that in C. utilisthe transport systems for glucose and maltose are both driven by the proton-motive force, but the mechanisms are different.

The role of the proton motive force and electron flow in light-driven solute transport in Rhodopseudomonas sphaeroides

1984 ◽  
Vol 50 (1) ◽  
pp. 88-88
Author(s):  
Marieke G. L. Elferink ◽  
Klaas J. Hellingwerf ◽  
Wil N. Konings
Keyword(s):  
Solute Transport ◽  
Electron Flow ◽  
Proton Motive Force ◽  
Motive Force ◽  
Rhodopseudomonas Sphaeroides

Na+ and K+ transport in a photodenitrifier, Rhodopseudomonas sphaeroides f.sp. denitrificans

1986 ◽  
Vol 64 (9) ◽  
pp. 946-952
Author(s):  
Balaram Kundu ◽  
D. J. D. Nicholas
Keyword(s):  
Proton Motive Force ◽  
Motive Force ◽  
Rhodopseudomonas Sphaeroides ◽  
Concomitant Increase ◽  
K Transport

Washed cells of Rhodopseudomonas sphaeroides f.sp. denitrificans depleted of cellular K+ by treatment with diethanolamine contained less than 5 mM K+. The K+-depleted cells accumulated 22Na+ only when there was no diethanolamine in the external buffer (50 mM Tris–HCl, pH 7.5). Studies with 22Na+-loaded cells indicate that this photodenitrifier had antiporters for Na+–H+, K+–Na+, and K+–H+ and lacked a respiration (denitrification) dependent Na+ pump. The K+–Na+ antiporter was electrogenic and required proton-motive force for its operation. Thus the addition of either NaCl or KCl to K+-depleted cells resulted in a depolarization of Δψ, both in light and in the dark, by 10–35 mV, which was partially compensated for by a concomitant increase (5–13 mV) in ΔpH.

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