Physical interaction between ALB3 and ALB4 in vivo. A, Immunoprecipitation with Anti-FLAG M2 Affinity Gel using 100 million chloroplasts isolated from plants stably overexpressing an ALB4-FLAG fusion under the Cauliflower mosaic virus 35S promoter. The chloroplasts were cross linked with 0.5 mm
DSP. TL, Total chloroplast lysate (0.45%); FT, flow through (0.45%); W, final (sixth) wash (approximately 4.5%); E, eluate (36%). ALB4 was detected with anti-ALB4 antibody; the size shift of ALB4 in the ALB4-FLAG sample compared with the wild type corresponds to the size of the FLAG tag. B, Immunoprecipitation (IP) with anti-ALB4 antibody (or with corresponding preimmune serum) using 100 million chloroplasts isolated from wild-type plants. Chloroplasts were cross linked with 0.5 mm
DSP. OE33, Oxygen-evolving complex 33 kD subunit; PSI-D, photosystem I subunit D; PC, plastocyanin.