title: BfpU, a soluble protein essential for type IV pilus biogenesis in enteropathogenic Escherichia coli.
abstract: A cluster of 14 genes located on the large plasmid of enteropathogenic Escherichia coli (EPEC) strains is sufficient to direct the biogenesis of the type IV bundle-forming pilus (BFP) in a recombinant E. coli host. The fifth gene in the cluster, bfpU, encodes a protein that is predicted to be localized to the periplasmic space. To determine whether BfpU is necessary for pilus biogenesis, the authors constructed a non-polar bfpU mutant EPEC strain by allelic exchange. The mutant strain was unable to perform localized adherence and auto-aggregation, two phenotypes associated with BFP expression, and it failed to make BFP. These phenotypes were restored to the bfpU mutant by a plasmid containing bfpU. There was no difference between the wild-type and bfpU mutant strains in their expression or processing of the pre-pilin protein or in their localization of the pilin protein in the inner and outer membranes. Fractionation studies revealed that BfpU is completely soluble and is detected in both the periplasm and the cytoplasm. Thus, BfpU represents a novel protein required for type IV pilus assembly.
authors.affiliation: Molecular and Cellular Biology Program, Division of Infectious Diseases1 and Comparative Medicine Program, Department of Medicine,2 University of Maryland, Baltimore, School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Schreiber
authors.affiliation: Molecular and Cellular Biology Program, Division of Infectious Diseases1 and Comparative Medicine Program, Department of Medicine,2 University of Maryland, Baltimore, School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Kelly D
authors.initials: KD
authors.lastname: Stone
authors.affiliation: Molecular and Cellular Biology Program, Division of Infectious Diseases1 and Comparative Medicine Program, Department of Medicine,2 University of Maryland, Baltimore, School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Strong
authors.affiliation: Molecular and Cellular Biology Program, Division of Infectious Diseases1 and Comparative Medicine Program, Department of Medicine,2 University of Maryland, Baltimore, School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: DeTolla
authors.affiliation: Institut für Mikrobiologie und Genetik, Georg-August Universität, Grisebachstrasse 8, 37077 Göttingen, Germany3.
authors.forename: Michael
authors.initials: M
authors.lastname: Hoppert
authors.affiliation: Molecular and Cellular Biology Program, Division of Infectious Diseases1 and Comparative Medicine Program, Department of Medicine,2 University of Maryland, Baltimore, School of Medicine, Baltimore, MD 21201, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Donnenberg
mesh_terms: D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000502:physiology*; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000502:physiology*; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D015151:Immunoblotting; D005810:Multigene Family; D009154:Mutation; D010957:Plasmids / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; C469813:BfpU protein, E coli; D029968:Escherichia coli Proteins