Updated project metadata. Aim was to analyse the in vivo start position of proteins in the import-mutant plant lines tic56-1 and ppi2 in contrast to wild type. Therefor we enriched N-terminal peptides originating from total protein of the three plant lines and detect them by mass spectrometry. This method is called TAILS and was described by Doucet et al. 2011 previously. For this analysis two experiments were done, further called TAILS1 and TAILS2. In TAILS1 total soluble protein from wild type and tic56-1 were analysed. N-termini of the wild type were labelled using normal formaldehyde during N-termini from tic56-1 were labelled with heavy formaldehyde. After labelling the two samples were combined and afterward treaded and measured together. In TAILS2 also membrane proteins were solubilized and additionally total protein from ppi2 plants was analysed. In this experiment the protein samples were treaded in the whole procedure separately and all three samples were labelled using normal formaldehyde. For peptide identification the raw-data were analysed using the Proteome Discoverer (search engine: SEQUEST) as well as MaxQuant (search engine: Andromeda). As variable modifications N-acetylation and methionine oxidation and as fixed modification carbamidomethylation of cysteins and dimethylation of lysine residues and N-termini (TAILS1: normal for wild type and heavy for tic56-1 sample) were allowed. For the Proteome Discoverer analysis the peptides diverse in the isotope labels (TAILS1) or the blocked N termini (N-terminal acetylation or dimethylation) were identified in distinct searches.