Fig. 1.

In vitro characterization of PSI activity and content in mutant strain PsaB-E613N. (A) NADP⁺ photoreduction measurements showing that electron transfer through PSI is limited by mutation PsaB-E613N. The SDs of the NADP⁺ photoreduction rates were calculated from a linear regression of the various time points at a given pc concentration. Measurements were performed with isolated PSI particles at 5 μg of Chl per ml, as described in Materials and Methods.(B) Quantification of PSI amounts in thylakoids isolated from the WT and E613N strains, upon SDS/PAGE fractionation and immunoblotting analysis using anti-PsaD antibodies.