Selection the most appropriate signal peptides for chloroplast targeting of the reporter protein based on bioinformatic tools and comparison with in vitro data

Chloroplasts cannot produce all the proteins they need and most chloroplastic proteins are encoded in the nucleus.These proteins are synthesized in the cytosol as precursors and transferred to chloroplasts. Its targeted approach, due to the existence of a specific sequence of target detection, is at the N-terminal of any chloroplast immature protein that is called signal peptide. In this study, we analuzed 200 signal peptides of different genes and hosts to select the most appropriate signal peptides for chloroplast. Cleavage sites of signal peptide, probability of their transfer to chloroplasts and their hydrophobicity was evaluated by bioinformatics tools such as Targetp, Tppred, PredSL, Predotor and protoscale. Moreover, in order to determine conserved amino acids in the structure, sequences were analyzed by BLAST program. In the next step, we predected the second structure of the GUS protein after binding of the signal peptide to the N-terminal. The most suitable signal peptides were selected from Spinacia oleracea, Arabidopsis thaliana, Petunia and Zea mays species. It is expected that the sequence of signal peptides can transfer repoeter protein into chloroplasts. Therefore, sequence of signal peptides will be added to the N-terminal of the gus gene and tranfored to the tobacco plant. In the following steps, the qualitative evaluation of the gus gene expression will be carried out to confirm the bioinformatics resuls.

Keywords:

Chloroplast , signal peptide , bioinformatic , JXV