Figure 3. Assembly of the newly synthesized thylakoid membrane proteins into complexes in intact chloroplasts.
(A) Silver-stained gel showing the distribution of thylakoid membrane proteins and protein complexes after two-dimensional BN/PAGE/SDS/PAGE separation. Molecular-mass standards for the second dimension SDS/PAGE are given on the left of the gel. (B) Autoradiogram showing the [35S]Met-labelled translation products in different thylakoid protein assemblies after a 10 min pulse followed by a 10 min chase with excess of unlabelled methionine in intact chloroplasts. D2 protein of the apparent D1 receptor complex is denoted by a white circle. (C) Longer exposure of the lower part of the autoradiogram in (B), showing the assembly of translated LMM proteins into PSII complexes. The labelled LMM subunits, which are already present in the D1 receptor complex, are indicated by open arrows and subunits of bigger PSII assemblies are indicated by black arrows. D1i (*), D1 intermediate; SU, subunit; SS, small subunit.