title: Mapping precursor-binding site on TatC subunit of twin arginine-specific protein translocase by site-specific photo cross-linking.
abstract: A number of secreted precursor proteins of bacteria, archaea, and plant chloroplasts stand out by a conserved twin arginine-containing sequence motif in their signal peptides. Many of these precursor proteins are secreted in a completely folded conformation by specific twin arginine translocation (Tat) machineries. Tat machineries are high molecular mass complexes consisting of two types of membrane proteins, a hexahelical TatC protein, and usually one or two single-spanning membrane proteins, called TatA and TatB. TatC has previously been shown to be involved in the recognition of twin arginine signal peptides. We have performed an extensive site-specific cross-linking analysis of the Escherichia coli TatC protein under resting and translocating conditions. This strategy allowed us to map the recognition site for twin arginine signal peptides to the cytosolic N-terminal region and first cytosolic loop of TatC. In addition, discrete contact sites between TatC, TatB, and TatA were revealed. We discuss a tentative model of how a twin arginine signal sequence might be accommodated in the Tat translocase.
authors.affiliation: Institute of Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Zellforschung (ZBMZ), University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Zoufaly
authors.forename: Julia
authors.initials: J
authors.lastname: Fröbel
authors.forename: Patrick
authors.initials: P
authors.lastname: Rose
authors.forename: Tobias
authors.initials: T
authors.lastname: Flecken
authors.forename: Carlo
authors.initials: C
authors.lastname: Maurer
authors.forename: Michael
authors.initials: M
authors.lastname: Moser
authors.forename: Matthias
authors.initials: M
authors.lastname: Müller
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000378:metabolism*; D001665:Binding Sites / Q000502:physiology; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity / Q000502:physiology
chemical_list: D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C473632:SufI protein, E coli; C499697:TatA protein, E coli; C473116:TatB protein, E coli; C461379:TatC protein, E coli; D001120:Arginine