FIGURE 4.

BN-PAGE and Western analysis of NaBr-extracted thylakoids. A, thylakoids were extracted with 1 m NaBr and sedimented by centrifugation. Stoichiometric amounts equivalent to 15 μg of chlorophyll of both the thylakoid pellet (NaBr p) and the supernatant (NaBr sn) were separated on 15% SDS-polyacrylamide gels and subjected to Western analyses with polyclonal antisera raised against TatA, TatB, and TatC. For comparison, stoichiometric amounts of untreated thylakoids, as well as of stromal extracts (stroma), were analyzed in parallel. x and y indicate the locations of proteins cross-reacting with the TatA antibody. B, in thykaloido transport experiment analyzing the 16/23 precursor with untreated (control) or NaBr-extracted thylakoids (NaBr). Thylakoids were washed twice with HM buffer, solubilized with digitonin, separated on a 5–13.5% Blue Native polyacrylamide gradient gel, and strained with Coomassie Blue (coomassie) or visualized by phosphorimaging (autoradiography). PS I, photosystem I; PS II, photosystem II; Cyt b₆f, cytochrome b₆f complex; LHC II, light-harvesting complex II.