title: Sequence analysis and protein import studies of an outer chloroplast envelope polypeptide.
abstract: A chloroplast outer envelope membrane protein was cloned and sequenced and from the sequence it was possible to deduce a polypeptide of 6.7 kDa. It has only one membrane-spanning region; the C terminus extends into the cytosol, whereas the N terminus is exposed to the space between the two envelope membranes. The protein was synthesized in an in vitro transcription-translation system to study its routing into isolated chloroplasts. The import studies revealed that the 6.7-kDa protein followed a different and heretofore undescribed translocation pathway in the respect that (i) it does not have a cleavable transit sequence, (ii) it does not require ATP hydrolysis for import, and (iii) protease-sensitive components that are responsible for recognition of precursor proteins destined for the inside of the chloroplasts are not involved in routing the 6.7-kDa polypeptide to the outer chloroplast envelope.
authors.affiliation: Botanisches Institut, Universität Munich, Federal Republic of Germany.
authors.forename: M
authors.initials: M
authors.lastname: Salomon
authors.forename: K
authors.initials: K
authors.lastname: Fischer
authors.forename: U I
authors.initials: UI
authors.lastname: Flügge
authors.forename: J
authors.initials: J
authors.lastname: Soll
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002736:Chloroplasts / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010944:Plants / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D013816:Thermodynamics
chemical_list: D008565:Membrane Proteins