FIGURE 2.

Photosynthetic multicompartment artificial cells. (A) a) Nanometric lipid vesicle with two complementary photoconverters (PSII and PR) and an ATP synthase reconstituted into the membrane. (b) Red light illumination triggers PSII that generates a proton gradient across the lipid membrane then exploited by ATP synthase for ATP synthesis. Green light activates PR causing proton depletion and impeding ATP synthesis. (c) Photosynthetic liposomes used as organelle energy modules when encapsulated in a giant vesicle, for actin polymerization and morphological change of the vesicle after optical stimulation (Lee et al., 2018). (B) Schematic representation of a giant lipid vesicles encapsulating nanometric liposome as artificial photosynthetic organelle, which consists of BR and ATP synthase. The ATP photo-produced can sustain mRNA synthesis (➀), guanosine diphosphate (GDP) phosphorylation (➁) or tRNA aminoacylation (➂) (Berhanu et al., 2019). (C) Chromatophores extracted from R. sphaeroides are encapsulated inside giant phospholipid vesicles made of POPC and illuminated to generate a proton motive force (Δp ∼ 130 mV) across the membrane. Co-encapsulated ADP, Pi, GTP, CTP, UTP, T7 RNA polymerase (dark green), and a DNA template give rise to an out-of-equilibrium system of coupled reactions: namely, photophosphorylation and DNA transcription. The biosynthesized mRNA is revealed by acridine orange (AO, pink), which binds it, forming a green-fluorescent complex (Altamura et al., 2021b).