Relevance to abiogenesis It has been proposed that the reductive acetyl-CoA pathway might have begun at
deep sea alkaline hydrothermal vents where
metal sulfides and
transition metals
catalyze the
prebiotic reactions of the reductive acetyl-CoA pathway. Recent experiments have tried to replicate this pathway by attempting to reduce CO2, with very little
pyruvate observed using
native iron (Fe0,
zerovalent Fe) as a
reducing agent (2 (10 μM). Joseph Moran and colleagues state that "it has been proposed that either the complete or “horseshoe” forms of the r
TCA cycle may have once been united with the acetyl CoA pathway in an ancestral, possibly prebiotic,
carbon fixation network". but more recent work challenges this conclusion as they argued that the previous study had "undersampled protein families, resulting in incomplete
phylogenetic trees which do not reflect
protein family evolution". However geological
evidence and
phylogenomic reconstructions of the
metabolic network of the common ancestors of archaea and bacteria support that LUCA fixed CO2 and relied on H2. == Historical references ==