title: The entire N-terminal half of TatC is involved in twin-arginine precursor binding.
abstract: Translocation of twin-arginine precursor proteins across the cytoplasmic membrane of Escherichia coli requires the three membrane proteins TatA, TatB, and TatC. TatC and TatB were shown to be involved in precursor binding. We have analyzed in vitro a number of single alanine substitutions in tatC that were previously shown to compromise in vivo the function of the Tat translocase. All tatC mutants that were defective in precursor translocation into cytoplasmic membrane vesicles concomitantly interfered with precursor binding not only to TatC but also to TatB. Hence structural changes of TatC that affect precursor targeting simultaneously abolish engagement of the twin-arginine signal sequence with TatB and block the formation of a functional Tat translocase. Since these phenotypes were observed for tatC mutations spread over the first half of TatC, this entire part of the molecule must globally be involved in precursor binding.
authors.affiliation: Institut für Biochemie und Molekularbiologie and Zentrum für Biochemie und Molekulare Zellforschung, Universität Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Holzapfel
authors.forename: Gottfried
authors.initials: G
authors.lastname: Eisner
authors.forename: Meriem
authors.initials: M
authors.lastname: Alami
authors.forename: Claire M L
authors.initials: CM
authors.lastname: Barrett
authors.forename: Grant
authors.initials: G
authors.lastname: Buchanan
authors.forename: Iris
authors.initials: I
authors.lastname: Lüke
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Betton
authors.forename: Colin
authors.initials: C
authors.lastname: Robinson
authors.forename: Tracy
authors.initials: T
authors.lastname: Palmer
authors.forename: Michael
authors.initials: M
authors.lastname: Moser
authors.forename: Matthias
authors.initials: M
authors.lastname: Müller
mesh_terms: D001120:Arginine / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D017434:Protein Structure, Tertiary
chemical_list: D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C461379:TatC protein, E coli; D001120:Arginine