Proton Transfer Dynamics at the Membrane/Water Interface: Dependence on the Fixed and Mobile pH Buffers, on the Size and Form of Membrane Particles, and on the Interfacial Potential Barrier

Cherepanov, Dmitry A.; Junge, Wolfgang; Mulkidjanian, Armen Y.

doi:10.1016/s0006-3495(04)74146-6

Cited by 65 publications

(53 citation statements)

References 71 publications

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“…The resulting barrier was determined to be approximately 6 RT adjacent to membranes made of carbon nanotubes (20). This observation does not explain why the barrier adjacent to GMO membranes (8.8-10 RT) is smaller than that in the vicinity of DPhPC membranes (12)(13)(14)(15)(16).…”

Section: Discussionmentioning

confidence: 88%

Protons migrate along interfacial water without significant contributions from jumps between ionizable groups on the membrane surface

Springer

Hagen²,

Cherepanov³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Kinetics of fluorescence changes on top of three different lipid bilayers due to lateral proton migration. The observation area was located at a distance of 70 μm from the area of proton release. Because all FPE molecules are surrounded by DPhPC or DPhPE molecules, they are anticipated to accept protons, which are released from these molecules. GMO does not possess ionizable moieties so that in case of two-dimensional diffusion, proton release from one FPE molecule seems to be required before the next FPE molecule may pick up the proton. Despite the huge differences in proton release rates from the different lipids, τ max for all three lipid bilayers was similar. That is, lateral proton diffusivity is independent of the choice of the lipid. The buffer contained 0.1 mM Capso (pH 9.0) and 100 mM NaCl. The F1 Wv/+ mice were then backcrossed to A/J mice for 10 generations, creating A/J N10 Wv/+ mice. These were then crossed to B6 Wv/+ mice to create F1 wildtype and F1 Wv/Wv mice for study. A/J mice had an increased airway resistance compared to B6 mice, and F1 mice had a naïve AHR phenotype equivalent to their parental A/J strain. F1 Wv/Wv mice displayed an airway resistance similar to normoresponsive B6 mice. Values represent mean ± SE, n = at least 10 in each group.

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Section: Discussionmentioning

confidence: 88%

Protons migrate along interfacial water without significant contributions from jumps between ionizable groups on the membrane surface

Springer

Hagen²,

Cherepanov³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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100

140

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“…But the membrane potential would also drive K + toward the cells, placing the entire burden for H + reentry on the affinity of H + for its binding site on the antiporter being much greater than the affinity of K + for its site. An alternative hypothesis is that the GCAM is like ATP synthesizing membranes (Kell, 1979;Cherepanov et al, 2004;Mulkidjanian and Cherepanov, 2006) and the H + concentration in the unstirred layer adjacent to the membrane lining the cavity is much higher than that in the bulk fluid. (Castagna et al, 1998) and CAATCH1 (cation amino acid transporter channel) (Feldman et al, 2000) from caterpillars and Na + /amino acid symport by AeAAT1i (Ae.…”

Section: Drosophila Nhas Are Plasma Membrane Proteinsmentioning

confidence: 99%

“…(Of course, the H + s that make up the 'higher c H SL ' are the same ones that make up the Δψ, which is another objection to the pmf concept). Direct evidence for a separate outer fluid-membrane interface phase and an outer bulk fluid phase is provided by Cherepanov, Mulkidjanian, Junge and associates (Cherepanov et al, 2003;Cherepanov et al, 2004) (for a review, see Mulkidjanian et al, 2005). They used light + is held at the fluid membrane interface (SL) by electrostatic attraction to its gegenion.…”

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confidence: 99%

Voltage coupling of primary H+ V-ATPases to secondary Na+- or K+-dependent transporters

Harvey

2009

Journal of Experimental Biology

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SUMMARY This review provides alternatives to two well established theories regarding membrane energization by H+ V-ATPases. Firstly, we offer an alternative to the notion that the H+ V-ATPase establishes a protonmotive force (pmf) across the membrane into which it is inserted. The term pmf, which was introduced by Peter Mitchell in 1961 in his chemiosmotic hypothesis for the synthesis of ATP by H+ F-ATP synthases, has two parts, the electrical potential difference across the phosphorylating membrane, Δψ, and the pH difference between the bulk solutions on either side of the membrane, ΔpH. The ΔpH term implies three phases – a bulk fluid phase on the H+ input side, the membrane phase and a bulk fluid phase on the H+ output side. The Mitchell theory was applied to H+ V-ATPases largely by analogy with H+ F-ATP synthases operating in reverse as H+ F-ATPases. We suggest an alternative, voltage coupling model. Our model for V-ATPases is based on Douglas B. Kell's 1979 `electrodic view' of ATP synthases in which two phases are added to the Mitchell model – an unstirred layer on the input side and another one on the output side of the membrane. In addition, we replace the notion that H+ V-ATPases normally acidify the output bulk solution with the hypothesis, which we introduced in 1992, that the primary action of a H+ V-ATPase is to charge the membrane capacitance and impose a Δψ across the membrane; the translocated hydrogen ions (H+s) are retained at the outer fluid–membrane interface by electrostatic attraction to the anions that were left behind. All subsequent events, including establishing pH differences in the outside bulk solution, are secondary. Using the surface of an electrode as a model, Kell's`electrodic view' has five phases – the outer bulk fluid phase, an outer fluid–membrane interface, the membrane phase, an inner fluid–membrane interface and the inner bulk fluid phase. Light flash,H+ releasing and binding experiments and other evidence provide convincing support for Kell's electrodic view yet Mitchell's chemiosmotic theory is the one that is accepted by most bioenergetics experts today. First we discuss the interaction between H+ V-ATPase and the K+/2H+ antiporter that forms the caterpillar K+ pump, and use the Kell electrodic view to explain how the H+s at the outer fluid–membrane interface can drive two H+ from lumen to cell and one K+ from cell to lumen via the antiporter even though the pH in the bulk fluid of the lumen is highly alkaline. Exchange of outer bulk fluid K+ (or Na+) with outer interface H+ in conjunction with (K+ or Na+)/2H+ antiport, transforms the hydrogen ion electrochemical potential difference, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{{\mu}}_{\mathrm{H}}\) \end{document}, to a K+electrochemical potential difference, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{{\mu}}_{\mathrm{K}}\) \end{document} or a Na+electrochemical potential difference, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{{\mu}}_{\mathrm{Na}}\) \end{document}. The \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{{\mu}}_{\mathrm{K}}\) \end{document} or \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\overline{{\mu}}_{\mathrm{Na}}\) \end{document} drives K+- or Na+-coupled nutrient amino acid transporters (NATs), such as KAAT1(K+ amino acid transporter 1), which moves Na+ and an amino acid into the cell with no H+s involved. Examples in which the voltage coupling model is used to interpret ion and amino acid transport in caterpillar and larval mosquito midgut are discussed.

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“…Moreover, a potential barrier represented by ordered water molecules on the surface of biological membranes would prevent H þ to diffuse. 12 How can enough H þ motive force be generated across inner mitochondrial membranes to synthesize ATP? Perhaps, this is a general open question for ATP synthase, as recently pointed out, 2 and the crux of the question.…”

Section: Introductionmentioning

confidence: 99%

Hypothesis of Lipid-Phase-Continuity Proton Transfer for Aerobic ATP Synthesis

Morelli

Ravera

Calzia

et al. 2013

J Cereb Blood Flow Metab

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The basic processes harvesting chemical energy for life are driven by proton (H þ ) movements. These are accomplished by the mitochondrial redox complex V, integral membrane supramolecular aggregates, whose structure has recently been described by advanced studies. These did not identify classical aqueous pores. It was proposed that H þ transfer for oxidative phosphorylation (OXPHOS) does not occur between aqueous sources and sinks, where an energy barrier would be insurmountable. This suggests a novel hypothesis for the proton transfer. A lipid-phase-continuity H þ transfer is proposed in which H þ are always bound to phospholipid heads and cardiolipin, according to Mitchell's hypothesis of asymmetric vectorial H þ diffusion. A phase separation is proposed among the proton flow, following an intramembrane pathway, and the ATP synthesis, occurring in the aqueous phase. This view reminiscent of Grotthus mechanism would better account for the distance among the F o and F 1 moieties of F o F 1 -ATP synthase, for its mechanical coupling, as well as the necessity of a lipid membrane. A unique active role for lipids in the evolution of life can be envisaged. Interestingly, this view would also be consistent with the evidence of an OXPHOS outside mitochondria also found in non-vesicular membranes, housing the redox complexes. Journal of Cerebral Blood INTRODUCTIONChemical energy for living matter is mostly supplied by the F o F 1 -ATP synthases (ATP synthases), multimeric proteins, which employ a rotary mechanism driven by proton-motive force. In turn, protons (H þ ) are translocated by electron transport chain (ETC). The structure and organization of ATP synthases, the 'splendid nanomolecular machine' 1 that mechanically synthesize ATP from ADP and Pi are well described, but how its rotation is driven by proton flow and how this energy is converted into catalysis are less clear.2 F 1 moiety is peculiar in that it is the only enzyme as yet known channeling energy to the reactant species by means of mechanical force. The topic of H þ cycling, pivotal in oxidative phosphorylation, is central in energy conversion.

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Proton Transfer Dynamics at the Membrane/Water Interface: Dependence on the Fixed and Mobile pH Buffers, on the Size and Form of Membrane Particles, and on the Interfacial Potential Barrier

Cited by 65 publications

References 71 publications

Protons migrate along interfacial water without significant contributions from jumps between ionizable groups on the membrane surface

Protons migrate along interfacial water without significant contributions from jumps between ionizable groups on the membrane surface

Voltage coupling of primary H+ V-ATPases to secondary Na+- or K+-dependent transporters

Hypothesis of Lipid-Phase-Continuity Proton Transfer for Aerobic ATP Synthesis

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