Figure 10.

Turnover of PSII Proteins in the RC47 Complex and Their Accumulation in A0 and Truncation Mutant A20, Both Lacking the psbC Gene Encoding the Inner PSII Antenna CP43.

(A) Thylakoid proteins and their radioactive labeling in cells of the CP43-less strains A0ΔCP43 (a and c) and A20ΔCP43 (b and d). Proteins were separated by two-dimensional blue-native SDS-PAGE and stained with Coomassie blue (a and b), and radioactive proteins were visualized by autoradiography (c and d). A total of 6 μg of chlorophyll per sample was loaded onto the gel, and α and β subunits of ATP synthase (αβ*) were used as internal standards to check correct loading of the gels.

(B) Quantification of the D1 protein in cells of A0ΔCP43 and A20ΔCP43. Thylakoid proteins were separated by denaturing SDS-PAGE on a 12 to 20% polyacrylamide gel containing 7 M urea, electroblotted onto a PVDF membrane, and immunodecorated using the antibodies raised against amino acid residues 59 to 76 of the D1 protein from Synechocystis, CP47, and PsaD. Correct protein loading was checked by Ponceau staining and documented by the staining intensity of the α and β subunits of ATP synthase (ATPsynth stain). A total of 1, 0.5, or 0.25 μg of chlorophyll was loaded onto the gel.