Figure 3.

Synthesis de novo of proteins in thylakoid membranes under strong light. Proteins in wild-type and transformed cells were pulse-labeled by incubation of cells at 25°C, for the indicated times, under strong light at 1000 μmol photons m⁻² s⁻¹ with standard aeration, in the presence of ³⁵S-labeled Met and Cys. Thylakoid membranes were isolated and proteins were separated by SDS-PAGE. A, representative radiogram of pulse-labeled proteins from thylakoid membranes. B, Quantitation of the relative levels of labeled thylakoid proteins in wild-type (open circles), EF-Tu (wild type; open triangles), and EF-Tu (C82S; closed squares) cells. Values are means ± sd (bars) of results from three independent experiments. The value for wild-type cells upon incubation for 30 min was taken as 1.0. Asterisks indicate statistically significant differences (P < 0.01; Student’s t test). WT, wild type.