Figure 2.

Amino acid sequences of signal peptides of the CtpAs (spinach, Scenedesmus and Synechocystis 6803) for targeting to the thylakoid. Sequences of the typical signal peptides for Tat-pathway (spinach PsbP) and Sec-pathway (spinach PsbO) are also aligned. Arginine and lysine residues which characteristically appear in these signals, are shown in red and blue, respectively. Hydrophobic domains are underlined. Downward arrows indicate residues under the “-3, -1 rule” of von Heijne [70,71] for the cleavage of the signal peptidase (thylakoidal processing protease) and the vertical broken line means cleavage site by the signal peptidase.