Figure 1.

Synthesis of hemeless cytochrome f escapes the CES process. Chloroplast translates from wild-type, ΔpetD, F52L-55V, and F52L-55VΔpetD strains (lanes from left to right). Whole-cell polypeptides were pulse-labeled for 5 min with [¹⁴C]acetate in the presence of an inhibitor of cytoplasmic translation and separated in SDS/12–18% polyacrylamide gels in the presence of 8 M urea. Arrowhead, positions of cytochrome f and SUIV deduced from comparison with known polypeptide patterns; ∗, position of apocytochrome f, which migrates slightly faster than holocytochrome f (20).