Figure 7.

Endogenous and imported Pftf is integrally associated with membranes of both pepper chromoplasts and pea chloroplasts. A, Analysis of identical samples from Figure 5E and the protease-treated thylakoid fraction following import into pea chloroplasts (lane MP^Chl) by 12.5% polyacrylamide SDS-PAGE and fluorography. The 65-kD mPftf and 13-kD protease-protected (pp) bands are indicated by arrows. B, Immunoblot analysis of chromoplast (containing 0.4 μg chlorophyll/mg protein) and chloroplast membranes. Proteins from chromoplast and chloroplast total membranes (lanes TM), NaOH-extracted membranes (lanes MN), and protease-treated membranes (lanes MP) were separated by 12.5% SDS-PAGE, transferred to nitrocellulose, probed with anti-Pftf, and visualized by enhanced chemiluminescence. The 65-kD mPftf and 13-kD protease-protected (pp) bands are indicated by arrows. C, Transmembrane prediction of the amino acid sequence of Pftf generated by the TMpred program. More positive values indicate residues more likely to occupy a transmembrane domain.