The evolution of oxygen-utilizing enzymes suggests early biosphere oxygenation
“…This suggests that PSII may retain features of type I RCs no longer seen in the PbRC or other RC2 complexes, which use an independently evolved antenna system, LH1 (Yu et al 2018 ). These features shared by PSII and type I RCs are consistent with recent evidence suggesting an early origin of photosynthetic water oxidation (Cardona et al 2019 ; Jabłońska and Tawfik 2021 ). …”
Section: Comparison Of the Gsbrc To Other Rcssupporting
“…This rather abrupt change in the character of S isotope ratios is thought to have occurred owing to formation of a UVblocking ozone layer. However, other researchers point to intervals or oases of elevated atmospheric oxygen as early as 3.1 Ga based on pulses of redox-sensitive trace elements in Archean sediments (e.g., Anbar et al 2007), as well as the postulated early appearance of microbial oxygen-utilizing enzymes (Jabłońska and Tawfik 2021). Those results suggest that a subset of oxidized mineral species might have formed prior to 2.4 Ga, during the Neoarchean Era.…”
Section: Stage 7 Great Oxidation Eventmentioning
“…Current analysis makes the involvement of an efficient fully aerobic bacterium related to the alpha-proteobacteria at eukaryotic origins perfectly feasible, because a protein family analysis demonstrated a burst of emerging oxygenases and other oxidoreductases, indicative of sufficient early biosphere oxygenation, to have occurred more than 3 billion years ago, well before the emergence of the eukaryotes (∼2 billion years ago). [36] Taken together, this makes a more accidental entry as depicted in Figure 1, instead of phagocytic uptake, seem to be more likely. However, the recent descriptions of some internal membrane structures in an archaeon (Ignicoccus hospitalis) have prompted speculation that the eukaryotic endomembrane system (and possibly phagocytosis) might have originated within the Archaea.…”
Section: Phagocytosis: Early or Late?mentioning
“…Current analysis makes the involvement of an efficient fully aerobic bacterium related to the alpha‐proteobacteria at eukaryotic origins perfectly feasible, because a protein family analysis demonstrated a burst of emerging oxygenases and other oxidoreductases, indicative of sufficient early biosphere oxygenation, to have occurred more than 3 billion years ago, well before the emergence of the eukaryotes (∼2 billion years ago). [ 36 ]…”
Section: Phagocytosis: Early or Late?mentioning