title: Two-partner secretion of gram-negative bacteria: a single β-barrel protein enables transport across the outer membrane.
abstract: The mechanisms of protein secretion by pathogenic bacteria remain poorly understood. In gram-negative bacteria, the two-partner secretion pathway exports large, mostly virulence-related "TpsA" proteins across the outer membrane via their dedicated "TpsB" transporters. TpsB transporters belong to the ubiquitous Omp85 superfamily, whose members are involved in protein translocation across, or integration into, cellular membranes. The filamentous hemagglutinin/FhaC pair of Bordetella pertussis is a model two-partner secretion system. We have reconstituted the TpsB transporter FhaC into proteoliposomes and demonstrate that FhaC is the sole outer membrane protein required for translocation of its cognate TpsA protein. This is the first in vitro system for analyzing protein secretion across the outer membrane of gram-negative bacteria. Our data also provide clear evidence for the protein translocation function of Omp85 transporters.
authors.affiliation: Institute of Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Zellforschung, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Enguo
authors.initials: E
authors.lastname: Fan
authors.forename: Silke
authors.initials: S
authors.lastname: Fiedler
authors.forename: Françoise
authors.initials: F
authors.lastname: Jacob-Dubuisson
authors.forename: Matthias
authors.initials: M
authors.lastname: Müller
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D058947:Bacterial Secretion Systems / Q000502:physiology*; D001886:Bordetella pertussis / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002474:Cell-Free System / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D058947:Bacterial Secretion Systems; D002352:Carrier Proteins; C098052:fhaC protein, Bordetella pertussis