Abstract
Molecular oxygen is a stable diradical. All O2-dependent enzymes employ a radical mechanism. Generated by cyanobacteria, O2 started accumulating on Earth 2.4 billion years ago. Its evolutionary impact is traditionally sought in respiration and energy yield. We mapped 365 O2-dependent enzymatic reactions of prokaryotes to phylogenies for the corresponding 792 protein families. The main physiological adaptations imparted by O2-dependent enzymes were not energy conservation, but novel organic substrate oxidations and O2-dependent, hence O2-tolerant, alternative pathways for O2-inhibited reactions. Oxygen-dependent enzymes evolved in ancestrally anaerobic pathways for essential cofactor biosynthesis including NAD+, pyridoxal, thiamine, ubiquinone, cobalamin, heme, and chlorophyll. These innovations allowed prokaryotes to synthesize essential cofactors in O2-containing environments, a prerequisite for the later emergence of aerobic respiratory chains.
Original language | American English |
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Pages (from-to) | 1692-1714 |
Number of pages | 23 |
Journal | FEBS Letters |
Volume | 598 |
Issue number | 14 |
DOIs | |
State | Published - 1 Jul 2024 |
Keywords
- aerobic metabolism
- evolution of aerobes
- evolution of respiration
- great oxidation event
- lateral gene transfer
- oxygen inhibition
All Science Journal Classification (ASJC) codes
- Genetics
- Molecular Biology
- Biophysics
- Structural Biology
- Biochemistry
- Cell Biology