Fig. 6: High PCCM performance requires low-pH thylakoids and a high-pH stroma. | Nature Plants

Fig. 6: High PCCM performance requires low-pH thylakoids and a high-pH stroma.

From: Modelling the pyrenoid-based CO2-concentrating mechanism provides insights into its operating principles and a roadmap for its engineering into crops

Fig. 6

a–f, pH values of the thylakoid lumen and the stroma are varied in a modelled chloroplast with an impermeable starch sheath employing passive CO2 uptake under air-level CO2 (a–c) (10 μM cytosolic; parameters as in Fig. 4d,e) or active HCO3− pumping under very low CO2 (d–f) (1 μM cytosolic, parameters as in Supplementary Fig. 17c,d). Normalized CO2 fixation flux (a,d) and ATP spent per CO2 fixed (b,e) as functions of the pH values in the two compartments are shown. c,f, Schematics of inorganic carbon pools and fluxes for the pH values indicated in a, b, d and e. White stars indicate the baseline pH values used in all other simulations.

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