Dissipation in Bioenergetic Electron Transfer Chains
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This paper examines the processes by which wasteful dissipation of free energy may occur in bioenergetic electron transfer chains. Frictionless transfer requires high rate constants in order to achieve a quasi-equilibrium steady-state. Previous results concerning the maximum power available from a photochemical source are recalled. The energetic performance of the bacterial reaction center is discussed, characterizing the processes that decrease either the quantum yield (recombination and obstruction) or the chemical potential (friction and non-equilibrated mechanisms). Considering the whole chain, diffusive carriers are potentially weaker links, due to kinetic limitation and short-circuiting reactions. It is suggested that the evolutionary trend has been to limit their number by lumping them into tightly bound protein complexes or, in a more flexible way, into labile supercomplexes.
Li Z, Zhou M, Ran X, Wang W, Wang H, Wang T Appl Environ Microbiol. 2025; 91(2):e0166824.
PMID: 39760519 PMC: 11837502. DOI: 10.1128/aem.01668-24.
Interheme electron tunneling in cytochrome c oxidase.
Kaila V, Johansson M, Sundholm D, Wikstrom M Proc Natl Acad Sci U S A. 2010; 107(50):21470-5.
PMID: 21106766 PMC: 3003029. DOI: 10.1073/pnas.1005889107.
What governs the reaction center excitation wavelength of photosystems I and II?.
Milo R Photosynth Res. 2009; 101(1):59-67.
PMID: 19585266 DOI: 10.1007/s11120-009-9465-8.
Noy D Photosynth Res. 2007; 95(1):23-35.
PMID: 17968671 DOI: 10.1007/s11120-007-9269-7.