Figure 4.

In vivo protein labeling of plastid-encoded thylakoid membrane proteins. A, Pulse labeling of thylakoid proteins of bfa3 and WT plants. After pulse labeling with [³⁵S]-Met for 20 min, thylakoid proteins were separated by SDS-urea-PAGE (left), and the labeled proteins were visualized by autoradiography (right). B, Pulse-chase labeling of thylakoid membrane proteins. After pulse labeling with [³⁵S]-Met for 20 min as in (A), the leaves were incubated with excess cold Met for an additional 0.5, 1, and 2 h. Labeled proteins were visualized by subsequent SDS-urea-PAGE and autoradiography. C, Assembly kinetics of the thylakoid protein complexes. After pulse-chase labeling as in B, except that the leaves were chased for 15, 30, and 60 min, and thylakoid protein complexes were separated by 2D BN/SDS-PAGE. The labeled proteins were visualized by autoradiography. CF₁α/β subunits are indicated as in Figure 3C. The position of intact chloroplast ATP synthases (CF₁-CF₀) and CF₁ subcomplex (CF₁) in the first dimension are indicated with arrows. The complex between the CF₁-CF₀ ATP synthase and CF₁ subcomplex (marked with an asterisk) is a putative complex containing the β-subunit.