Two-ion theory of energy coupling in ATP synthesis rectifies a fundamental flaw in the governing equations of the chemiosmotic theory

2017 ◽  
Vol 230 ◽  
pp. 45-52 ◽  
Author(s):  
Sunil Nath
Keyword(s):  
Atp Synthesis ◽  
Energy Coupling ◽  
Chemiosmotic Theory ◽  
Governing Equations

scholarly journals Entropy Production and Its Application to the Coupled Nonequilibrium Processes of ATP Synthesis

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 746 ◽  
Author(s):  
Sunil Nath
Keyword(s):  
Experimental Data ◽  
Entropy Production ◽  
Physiological State ◽  
Atp Synthesis ◽  
Energy Coupling ◽  
Energy Transduction ◽  
Theoretical Research ◽  
Thermodynamic Efficiency ◽  
Chemiosmotic Theory ◽  
Torsional Mechanism

Starting from the universal concept of entropy production, a large number of new results are obtained and a wealth of novel thermodynamic, kinetic, and molecular mechanistic insights are provided into the coupling of oxidation and ATP synthesis in the vital process of oxidative phosphorylation (OX PHOS). The total dissipation, Φ , in OX PHOS with succinate as respiratory substrate is quantified from measurements, and the partitioning of Φ into the elementary components of ATP synthesis, leak, slip, and other losses is evaluated for the first time. The thermodynamic efficiency, η , of the coupled process is calculated from the data on Φ and shown to agree well with linear nonequilibrium thermodynamic calculations. Equations for the P/O ratio based on total oxygen consumed and extra oxygen consumed are derived from first principles and the source of basal (state 4) mitochondrial respiration is postulated from molecular mechanistic considerations based on Nath’s two-ion theory of energy coupling within the torsional mechanism of energy transduction and ATP synthesis. The degree of coupling, q , between oxidation and ATP synthesis is determined from the experimental data and the irreversible thermodynamics analysis. The optimality of biological free energy converters is explored in considerable detail based on (i) the standard biothermodynamic approach, and (ii) a new biothermokinetic approach developed in this work, and an effective solution that is shown to arise from consideration of the molecular aspects in Nath’s theory is formulated. New experimental data in state 4 with uncouplers and redox inhibitors of OX PHOS and on respiratory control in the physiological state 3 with ADP and uncouplers are presented. These experimental observations are shown to be incompatible with Mitchell’s chemiosmotic theory. A novel scheme of coupling based on Nath’s two-ion theory of energy coupling within the torsional mechanism is proposed and shown to explain the data and also pass the test of consistency with the thermodynamics, taking us beyond the chemiosmotic theory. It is concluded that, twenty years since its first proposal, Nath’s torsional mechanism of energy transduction and ATP synthesis is now well poised to catalyze the progress of experimental and theoretical research in this interdisciplinary field.

Molecular Features of Energy Coupling in the F0F1 ATP Synthase

Physiology ◽  
1999 ◽  
Vol 14 (1) ◽  
pp. 40-46
Author(s):  
Robert K. Nakamoto
Keyword(s):  
Atp Synthase ◽  
Catalytic Domain ◽  
Atp Synthesis ◽  
Energy Coupling ◽  
F0f1 Atp Synthase ◽  
Molecular Features ◽  
Rotary Mechanism ◽  
Transport Domain

H+ translocation is coupled to ATP synthesis in the F0F1 ATP synthase via a rotary mechanism. Catalytic turnover, site-site cooperativity, and H+ transport obligatorily involve rotation of a set of subunits. The transport domain in the membranous F0 and the catalytic domain in the F1 are mechanisms designed for generating torque.

scholarly journals A critical appraisal of evidence for localized energy coupling. Kinetic studies on liposomes containing bacteriorhodopsin and ATP synthase

1985 ◽  
Vol 230 (2) ◽  
pp. 543-549 ◽  
Author(s):  
R L Van der Bend ◽  
J Petersen ◽  
J A Berden ◽  
K Van Dam ◽  
H V Westerhoff
Keyword(s):  
Electron Transfer ◽  
Atp Synthase ◽  
Critical Appraisal ◽  
Atp Synthesis ◽  
Kinetic Studies ◽  
Energy Coupling ◽  
Proton Pumps ◽  
Specific Interactions ◽  
Mitochondrial Atp Synthase ◽  
Different Levels

In intact systems (chloroplasts, mitochondria and bacteria) many experiments have been reported which are indicative of localized coupling between ATP synthase and electron transfer complexes. We have carried out similar experiments with a system in which we may assume that specific interactions between the proton pumps are absent: reconstituted vesicles containing bacteriorhodopsin and yeast mitochondrial ATP synthase. The only experiment that gives results which differ from those previously published for intact systems concerns the effect of uncouplers on the rate of ATP synthesis at different levels of inhibition of the ATP synthase. We propose that this type of experiment may discriminate between localized and delocalized coupling.

scholarly journals Photosensitive phosphoproteins in Halobacteria: regulatory coupling of transmembrane proton flux and protein dephosphorylation.

1981 ◽  
Vol 91 (3) ◽  
pp. 895-900 ◽  
Author(s):  
E N Spudich ◽  
J L Spudich
Keyword(s):  
Protein Phosphorylation ◽  
Action Spectrum ◽  
Atp Synthesis ◽  
Energy Coupling ◽  
Proton Flux ◽  
Protonmotive Force ◽  
Proton Efflux ◽  
Ph Gradients ◽  
Protein Dephosphorylation ◽  
Reversible Protein Phosphorylation

A photoregulated reversible protein phosphorylation system controlled by the halobacterial rhodopsins was recently reported. The results presented in this paper identify the initial steps in the pathway from the absorption of light to the photoregulated protein phosphorylation and dephosphorylation reactions. Action spectrum, biochemical, and genetic analyses show that the proton pump bacteriorhodopsin mediates light-induced dephosphorylation of three photoregulated phosphoproteins. Light absorbed by bacteriorhodopsin is used to establish a proton efflux from the cells. The increase in the inwardly directed protonmotive force (pmf) from this efflux induces dephosphorylation of the three phosphoproteins, as demonstrated by the effects of the protonophore CCCP and of artificially imposed transmembrane pH gradients. Upon darkening the cells, cessation of the proton efflux through bacteriorhodopsin causes a decrease in pmf, which induces rephosphorylation of the proteins. Pmf appears to function as a regulator rather than a driving force in this system. Measurements of pmf-driven ATP synthesis in our conditions indicate the regulation of protein phosphorylation by pmf is probably not a consequence of proton flux through the H+ ATPase, a known energy coupling structure in these cells. The properties of this system may indicate the existence of a pmf detector which regulates kinase or phosphatase activity; i.e., a regulatory coupling device.

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