title: A sequence-specific function for the N-terminal signal-like sequence of the TonB protein.
abstract: TonB is a proline-rich protein which provides a functional link between the inner and outer membranes of Gram-negative bacteria. TonB is anchored to the inner membrane via an N-terminal signal-like sequence and spans the periplasm, interacting with transport receptors in the outer membrane. We have investigated the role of the N-terminal signal-like peptide in TonB function. Replacement of the N-terminal sequence with heterologous sequences indicates that it has at least three distinct roles in TonB function: (i) to facilitate translocation of TonB across the cytoplasmic membrane; (ii) to anchor TonB to the cytoplasmic membrane; (iii) a sequence-specific functional interaction with the ExbBD proteins.
authors.affiliation: Imperial Cancer Research Fund Laboratories, University of Oxford, John Radcliffe Hospital, UK.
authors.forename: M
authors.initials: M
authors.lastname: Karlsson
authors.forename: K
authors.initials: K
authors.lastname: Hannavy
authors.forename: C F
authors.initials: CF
authors.lastname: Higgins
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001692:Biological Transport; D016384:Consensus Sequence; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006090:Gram-Negative Bacteria / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C052874:ExbB protein, E coli; D008565:Membrane Proteins; D021382:Protein Sorting Signals; C062093:tolA protein, E coli; C057616:tonB protein, Bacteria; C489181:tonB protein, E coli; C060792:tolQ protein, E coli; C060790:exbD protein, E coli