title: A Toc75-like protein import channel is abundant in chloroplasts.
abstract: Chloroplasts import post-translationally most of their constituent polypeptides via two distinct translocon units located in the outer and inner envelope. The protein import channel of the translocon of the outer envelope of chloroplasts, Toc75, is the most abundant protein in that membrane. We identify a novel Toc75 homologous protein, atToc75-V, a prominent protein that is clearly localized in the chloroplastic outer envelope. Phylogenetic analysis indicates that Toc75-V is more closely related to its prokaryotic ancestors than to Toc75 from plants. The presence of a second translocation channel suggests that alternative, previously unrecognized import routes into chloroplasts might exist.
authors.affiliation: Department für Biologie I, Menzinger Strasse 67, Ludwig-Maximilians-Universität, D-80638 München, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Eckart
authors.forename: Lutz
authors.initials: L
authors.lastname: Eichacker
authors.forename: Karen
authors.initials: K
authors.lastname: Sohrt
authors.forename: Enrico
authors.initials: E
authors.lastname: Schleiff
authors.forename: Lisa
authors.initials: L
authors.lastname: Heins
authors.forename: Jürgen
authors.initials: J
authors.lastname: Soll
mesh_terms: D000595:Amino Acid Sequence; D002736:Chloroplasts / Q000737:chemistry*; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000737:chemistry*; D010940:Plant Proteins; D011498:Protein Precursors / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D008565:Membrane Proteins; C103933:OEP75 protein precursor, plant; D010940:Plant Proteins; D011498:Protein Precursors