Uncompensated contribution of LCI1 (C, D), LCIB (E, F), and LCIA (G, H) in a wild-type background at pH 6 (open squares), pH 7.3 (closed squares) and pH 9 (red circles) plotted against calculated CO2 concentration (left) and HCO3− concentration (right). The CO2 and HCO3− concentration ranges covered are 0–25 μM and 0–120 μM, respectively. A and B are the original O2 evolution rates of the wild type. Note that the Y-axis scales on the original O2 evolution plots (A, B) are different than those on the uncompensated contribution plots (C–H). Uncompensated contributions were calculated by subtracting O2 evolution rates of the single mutant from wild type strain (LCI1 in wild type = 21gr-lci1; LCIB in wild type = 21gr-pmp1; LCIA in wild type = 21gr-lcia).