Murburn concept: A tangible bioenergetic rationale for the origin, sustenance, termination, and evolution of life

Abstract

Since 2017, I have argued that affinity/contact-based electron transport chain (ETC) and chemiosmotic rotary ATP synthesis (CRAS) explanation fail to reason the workability or evolution of cellular bioenergetics. Cyanobacteria (Prochlorococcus) can both respire and photosynthesize. In these systems, the aqueous milieu of <0.1 femtoliter (pH 8) cannot afford any free protons to build ‘pmf’’, thereby negating chemiosmosis. The anti-parallel ETCs (NADH→H2O in respiration and H2O→NADH in photosynthesis) would lead to futile cycles, owing to the commonality of cytochromes b6f and c1. Aphids of genus Acyrthosiphon use the inbuilt carotenoid pigments to reduce NAD and synthesize ATP, without elaborate setups like Z-scheme. The classical perceptions deem archaeans to have a unique bioenergetic history, distinct from bacteria/eukarya. Although it is known that archaea lack FoF1ATP(synth)ase, the ‘molecular motor’ is otherwise believed to be conserved in bacterial/eukaryotic systems. However, the genes of Complex V are not clubbed/linked in proteobacterial Rickettsia prowazekii. Several parasitic and a free-living alveolate Tetrahymena thermophila lack essential proteins of Fo module. Complex V is completely absent in the blood-stage malarial parasite (Plasmodium berghei) and Buchnera aphidicola (a proteobacterium, endosymbiont of cedar bark aphid). Monocercomonoides (a flagellate oxymonad rodent-gut symbiont) and human erythrocytes generate ATP without mitochondria! The recently discovered cnidarian parasite Henneguya salminicola does not have respiratory Complexes I, III & IV, the purported classical proton pumps. While the ETC-CRAS model is incompatible with these facts, the newly available murburn alternative accommodates them. The principles of scientific pursuits and Ockham’s razor decide in favor of the murburn model of bioenergetics.