title: Functional domains of the ferredoxin transit sequence involved in chloroplast import.
abstract: In order to analyze the information content of a chloroplast transit sequence, we have constructed and analyzed by in vitro assays seven substitution and 20 deletion mutants of the ferredoxin transit sequence. The N-terminal part and the C-terminal part are important for targeting, and in addition the C-terminal region is required for processing. A third region is important for translocation but not for the initial interaction with the envelope. A fourth region is less essential for in vitro import. Purified precursors were tested for their ability to compete for the in vitro import of radiolabeled wild-type precursor, which confirmed the important role in chloroplast recognition of both the N- and the C-terminal domain of the transit sequence. Monolayer experiments showed that the N terminus was mainly involved in the insertion into mono-galactolipid-containing lipid surfaces whereas the C terminus mediates the recognition of negatively charged lipids. A sequence comparison to other transit sequences suggests that the domain structure of the ferredoxin transit sequence can be extended to these sequences and thus reveals a general structural design of transit sequences.
authors.affiliation: Institute of Biomembranes, Utrecht University, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Pilon
authors.forename: H
authors.initials: H
authors.lastname: Wienk
authors.forename: W
authors.initials: W
authors.lastname: Sips
authors.forename: M
authors.initials: M
authors.lastname: de Swaaf
authors.forename: I
authors.initials: I
authors.lastname: Talboom
authors.forename: R
authors.initials: R
authors.lastname: van 't Hof
authors.forename: G
authors.initials: G
authors.lastname: de Korte-Kool
authors.forename: R
authors.initials: R
authors.lastname: Demel
authors.forename: P
authors.initials: P
authors.lastname: Weisbeek
authors.forename: B
authors.initials: B
authors.lastname: de Kruijff
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002736:Chloroplasts / Q000378:metabolism*; D005288:Ferredoxins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009838:Oligodeoxyribonucleotides; D011499:Protein Processing, Post-Translational; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
chemical_list: D005288:Ferredoxins; D009838:Oligodeoxyribonucleotides