Figure 2

Import of FcpD-GFP is charge-dependent. GFP is directed to the stroma by means of the FcpD-BTS of P. tricornutum irrespective of the particular positively charged residue (a, c, e, f). Negative charge of the precursor N-terminus impedes import within the ER (b). Neutralising the charges leads to GFP import into the PPC (d). In the scheme of the investigated precursors (on the right side), the amino acid sequence of the FcpD-transit peptide and the very N-terminus of GFP is denoted with charged residues in bold capitals in the topmost line. In further lines, only the charged amino acids at the respective position are indicated. Signal peptide in red (SP), transit peptide in blue (TP), GFP in green (eGFP). DIC = differential interference contrast, Plastid = chlorophyll autofluorescence, GFP = GFP fluorescence, Merge = merged plastid and GFP images. Scale bar = 10 μm.