Steady-state levels of chlorophyll precursors were measured from leaves of WT and acd2 plants grown for 15 days or 20 days. This experiment was done twice with similar results. Error bars represent SD (n=2).
(a) Mg-protoporphyrin IX (Mg-Proto IX), Mg-protoporphyrin IX monomethyl ester (MPE) and protoporphyrin IX (PPIX) contents in WT and acd2 plants.
(b) Chlorophyllide contents in WT and acd2 plants.
(c) Quenching of ACD2 protein fluorescence by PPIX. The percentage (%) decrease in intrinsic fluorescence of purified ACD2 protein, due to PPIX binding, was plotted against the concentration of PPIX and the Kd was found to be 0.31 ± 0.02 μM. This experiment was done three times with similar results.