The protein translocation channel at the outer envelope membrane of chloroplasts (Toc75) is synthesized as a larger precursor with an N-terminal transit peptide. Within the transit peptide of the pea Toc75, a major por-tion of the 10 amino acid long stretch that contains nine glycine residues was shown to be necessary for directing the protein to the chloroplast outer membranein vitro [Inoue K & Keegstra K (2003) Plant J34, 661–669].