Convergent Evolution of Coenzyme Metabolism in <i>Methanosarcina mazei</i>: Insights Into Primitive Life and Metabolic Adaptations

The convergent evolution of coenzyme metabolism in methanogens provides critical insights into primitive life and metabolic adaptations. This study investigated the molecular evolution and functional dynamics of eight coenzymes and cofactors in Methanosarcina mazei, a model methanogen essential for methane production and energy conservation in anaerobic environments. Phylogenetic and genetic diversity analyses of the 706 protein sequences revealed conserved evolutionary trajectories interspersed with lineage-specific adaptations driven by gene duplication, horizontal gene transfer, and selective pressures. Key findings included the purifying selection of methanofuran (Tajima's D = -2.9589) and coenzyme A (Tajima's D = -2.8555), indicating the conservation of critical metabolic functions. The coenzyme B biosynthesis pathway showed balanced selection (Tajima's D = 2.38602), reflecting its evolutionary plasticity. Phylogenetic analyses linked coenzyme F₄₂₀ biosynthetic enzymes closely to Methanosarcina horonobensis, while coenzyme F₄₃₀ enzymes highlighted prokaryotic specialization distinct from their eukaryotes. Coenzyme M biosynthetic genes have demonstrated unique evolutionary connections with species across domains, such as Methanothermobacter thermautotrophicus and Gekko japonicus, emphasizing their broad adaptive significance. These evolutionary trajectories reveal how M. mazei optimized its metabolic pathways to thrive in extreme anaerobic environments, bridging ancient metabolic systems from the Last Universal Common Ancestor with contemporary ecological adaptations.