Chemiosmotic and murburn explanations for aerobic respiration: Predictive capabilities, structure-function correlations and chemico-physical logic

• Published in: Archives of biochemistry and biophysics Vol. 676; p. 108128
• Main Authors: Manoj, Kelath Murali, Soman, Vidhu, David Jacob, Vivian, Parashar, Abhinav, Gideon, Daniel Andrew, Kumar, Manish, Manekkathodi, Afsal, Ramasamy, Surjith, Pakshirajan, Kannan, Bazhin, Nikolai Mikhailovich
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.11.2019
• Subjects: Adenosine Triphosphate - metabolism; Aerobic respiration; Aerobiosis; Bioenergetics; Cell Respiration; Chemiosmosis; Kinetics; Mitochondrial complexes; Models, Biological; Murburn concept; Oxidation-Reduction; Proton motive force; ROS; Thermodynamics; Trans-membrane potential; Thermodynamics; Bioenergetics; Mitochondrial complexes; Aerobic respiration; ROS; Kinetics; Proton motive force; Murburn concept; Trans-membrane potential; Chemiosmosis
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/j.abb.2019.108128

Since mid-1970s, the proton-centric proposal of ‘chemiosmosis’ became the acclaimed explanation for aerobic respiration. Recently, significant theoretical and experimental evidence were presented for an oxygen-centric ‘murburn’ mechanism of mitochondrial ATP-synthesis. Herein, we compare the predictive capabilities of the two models with respect to the available information on mitochondrial reaction chemistry and the membrane proteins' structure-function correlations. Next, fundamental queries are addressed on thermodynamics of mitochondrial oxidative phosphorylation (mOxPhos): (1) Can the energy of oxygen reduction be utilized for proton transport? (2) Is the trans-membrane proton differential harness-able as a potential energy capable of doing useful work? and (3) Whether the movement of miniscule amounts of mitochondrial protons could give rise to a potential of ~200 mV and if such an electrical energy could sponsor ATP-synthesis. Further, we explore critically if rotary ATPsynthase activity of Complex V can account for physiological ATP-turnovers. We also answer the question- “What is the role of protons in the oxygen-centric murburn scheme of aerobic respiration?” Finally, it is demonstrated that the murburn reaction model explains the fast kinetics, non-integral stoichiometry and high yield of mOxPhos. Strategies are charted to further demarcate the two explanations' relevance in the cellular physiology of aerobic respiration. •Chemiosmotic & murburn explanations for aerobic respiration are compared.•Structure-function correlations of the two models are elucidated graphically.•Thermodynamics & reaction logic of both theories are critically assessed.•Kinetics & variable stoichiometry of aerobic respiration is tangibly explained.