2025 ¡ The FEBS Journal ¡ Blackwell Publishing ¡ added 2026-04-21
Corrinoids are cobaltâcontaining tetrapyrroles. They include adenosylcobalamin (vitamin B12) and cobamides that function as cofactors and coenzymes for methyl transfer, ra Show more
Corrinoids are cobaltâcontaining tetrapyrroles. They include adenosylcobalamin (vitamin B12) and cobamides that function as cofactors and coenzymes for methyl transfer, radicalâdependent and redox reactions. Though cobamides are the most complex cofactors in nature, they are essential in the acetylâCoA pathway, thought to be the most ancient CO2âfixation pathway, where they perform a pterinâtoâcobaltâtoânickel methyl transfer reaction catalyzed by the corrinoid ironâsulphur protein (CoFeS). CoFeS occurs in H2âdependent archaeal methanogens, the oldest microbial lineage by measure of physiology and carbon isotope data, dating corrinoids to ca. 3.5âbillion years. However, CoFeS and cobamides are also essential in the acetylâCoA pathway of H2âdependent bacterial acetogens. To determine whether corrin biosynthesis was established before archaea and bacteria diverged, whether the pathways arose independently or whether cobamide biosynthesis was transferred from the archaeal to the bacterial lineage (or vice versa) during evolution, we investigated phylogenies and structural data for 26 enzymes of corrin ring and lower ligand biosynthesis. The data trace cobamide synthesis to the common ancestor of bacteria and archaea, placing it in the last universal common ancestor of all lifeforms (LUCA), while pterinâdependent methyl synthesis pathways likely arose independently postâLUCA in the lineages leading to bacteria and archaea. Enzymes of corrin biosynthesis were recruited from preexisting ancient pathways. Evolutionary forerunners of CoFeS function were likely Feâ, Niâ and Coâcontaining solidâstate surfaces, which, in the laboratory, catalyze the reactions of the acetylâCoA pathway from CO2 to pyruvate under serpentinizing hydrothermal conditions. The data suggest that enzymatic corrin biosynthesis replaced insoluble solidâstate catalysts that tethered primordial CO2 assimilation to the Earth's crust, suggesting a role for corrin synthesis in the origin of freeâliving cells. Show less