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Chloroplast import and sequential maturation of pea carbonic anhydrase: the roles of various parts of the transit peptide
Author(s) -
Forsman Cecilia,
Pilon Marinus
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01391-d
Subject(s) - transit peptide , chloroplast , peptide , chloroplast stroma , biochemistry , cleavage (geology) , carbonic anhydrase , cytosol , biology , chemistry , microbiology and biotechnology , thylakoid , plastid , enzyme , gene , paleontology , fracture (geology)
Chloroplast pea carbonic anhydrase is synthesised in the cytosol with an unusually long bipartite N‐terminal extension of the mature sequence previously proposed to serve as a transit peptide. Studies of import into pea chloroplasts show that the N‐terminal 69 amino acids of the previously proposed transit peptide is sufficient for translocation and localisation to the stroma, while the acidic C‐terminal part does not seem to have any function in these processes. Processing of the in vitro imported precursors is shown to be at a new cleavage site located in the middle of the actual transit peptide. The results indicate that maturation occurs in more than one step. The time‐course does not seem to be dependent on the age of the chloroplast but on the age of the translocated precursor.