Metabolism in anaerobic environments, Unification of Photoautotrophy, Chemoautotrophy and Photoelectric autotrophy

This topic is related to Is RuBisCO going to be added as an enzyme/organelle.

Splitting up photosynthesis

Considering that Luca will start from an anaerobic environment, we need some anaerobic autotrophic.
We have the current ways about chemoautotrophism: Rusticyanin requires Oxygen, Chemosynthesizing Protein directly converts hydrogen sulfide into glucose.

I think Chemosynthesizing Protein is amiss, its hydrogen sulfide is directly converted into glucose without consuming energy. But in reality, purple sulfur bacteria use hydrogen sulfide as hydrogen source to synthesize glucose with light energy. This process does not release oxygen.

Before the emergence of oxygen producing photosynthesis, Sulfate(SO4-) is the most widely oxidant in primitive ocean, the primitive ocean is filled with hydrogen, ammonia and hydrogen sulfide. They are excellent energy source and more efficient hydrogen sources than water until the increase in oxygen concentration suppresses their concentration. But there is no hydrogen gas in the current game, ammonia is limited to only reproduction, and hydrogen sulfide is directly converted into glucose.

Abandoned ideas

I tend to separate energy supply, hydrogen source decomposition, and carbon sequestration. hydrogen source decomposition consumes ATP and produces important NADPH, which is provided on carbon sequestration.

I have an idea that hydrogen source decomposition is limited to use ATP from energy supply in adjacent position, such as photosynthetic pigment(Chlorophyll, Carotenoids, and Retinene). It would help to achieve that similar to oxygen photosynthesis in cyanobacteria and sulfur photosynthesis in archaea.[Additionally, we should consider that thylakoid has the overall effect of using light energy to decompose water. But it is the only intracellular membrane structure of bacteria, so we should pay special attention to it.]

edit: Nitrogen in acidic and reducibility primitive oceans should exist in the form of ammonium Instead of ammonia.

What does adjacent mean? In the same organelle?

Collaboration between two adjacent components, multiple components work as a whole.The purpose is to Avoid consuming ATP produced by glucose to produce glucose. Perhaps there should be other methods.


I went to further understand the evolution of photosynthesis.

It seems that the energy supply and hydrogen source decomposition should be integrated into one structure, Hydrogen source decomposition exists as an upgrade of structure.

One possible solution is that the energy supply structure upgraded with hydrogen source decomposition function not only generates ATP but also NADPH, which are required for glucose synthesis. The amount of NADPH will limit the ATP used for glucose synthesis within its autotrophic capacity range.

This design is not only applicable for photosynthesis, but also compatible with chemoautotrophic effects. The existence of Photoelectric autophy and Carboxysome means it has realism.

Photoelectric autophy may be that life began to try to use light energy, while life may have directly used hydrogen gas for carbon dioxide fixation earlier on. The Wood Ljungdahl pathway is widely present in anaerobic bacteria and archaea.

Carboxysome is the unique inner membrane structure of autotrophic bacteria, which exists in chemoautotrophic Thiobacillus, Beggiatoa and some photoautotrophic cyanobacteria.

If Photoelectric autophy is considered, rutile can be added as a new rock to provide photoelectrons for surrounding cells under light, and new extracellular structures can be added to convert photoelectrons into NADPH and ATP.

It is worth mentioning that Nitrosopululus maritimus has the ability to produce oxygen without the need for light, although the production is only sufficient for their own use.

Taking the Optical System as an Example (Pigment Evolution Route)

porphyrin [free] (Adaptive radiation, light ATP generation)→bacteriochlorophyll [photosynthetic membrane] (Adaptive radiation, light ATP generation, hydrogen source: hydrogen sulfide)→chlorophyll [thylakoid] (Adaptive radiation, light ATP generation, hydrogen source: hydrogen sulfide, water{ Oxygen production})

Carotene [free] (Adaptive radiation, Weak light ATP generation)→Retinal [photosynthetic membrane] (Adaptive radiation,Strong light ATP generation, hydrogen source: hydrogen sulfide)

Eumelanin [vacuole] (Extreme radiation adaptation)→Allomelanin[vacuole] (Extreme radiation adaptation, high radiation ATP generation, hydrogen source: water)

Evolution of photosystem
RC 1: reducing fuction, producing NADPH
RC 2: proton motive fuction, producing ATP, (Water decomposition, from OEC)

Heliobacteria was found to have a relatively primitive single photoreaction center.

I have found some information about oxygen evolution complexes (OECs), which are the only protein complexes in nature that can decompose water at ordinary temperature.
If passive protease is implemented, it can be used as an unlocking condition for oxygen production photosynthesis.