title: Identification of flagellar hook and basal body gene products (FlaFV, FlaFVI, FlaFVII and FlaFVIII) in Salmonella typhimurium.
abstract: The flagellar genes flaFV, flaFVII, and flaFVIII of Salmonella typhimurium were cloned, and their presence on a given plasmid was verified by complementation of Escherichia coli mutants defective in the homologous genes. The gene products were identified by radiolabeling in a minicell system as being proteins of the following molecular masses: FlaFV, 42 kilodaltons (kDa); FlaFVI, 32 kDa; FlaFVII, 30 kDA; and FlaFVIII, 27 kDa. These data, together with isoelectric focusing data, confirm gene product assignments of flagellar components made indirectly from mutant studies. Flagellar components are transported by either a signal peptide-dependent or a flagellar-specific pathway. Consistent with its location in the outer membrane ring of the basal body, protein FlaFVIII seems to use the signal peptide-dependent pathway, since it was synthesized in a precursor form and processed, presumably by peptide cleavage, to a mature form; the maturation process was inhibited by addition of a proton ionophore. Proteins synthesized in minicells were localized as follows: FlaFVI was localized to the soluble fraction (cytoplasm); pre-FlaFVIII and FlaFVIII were localized to the particulate fraction (membrane or high-molecular-weight aggregate); FlaFV and FlaFVII were localized to both fractions. The significance of these locations in terms of known or suspected roles in the flagellar apparatus is discussed.
authors.forename: M
authors.initials: M
authors.lastname: Homma
authors.forename: K
authors.initials: K
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Iino
authors.forename: R M
authors.initials: RM
authors.lastname: Macnab
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000032:analysis; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000032:analysis; D005407:Flagella; D005796:Genes; D005798:Genes, Bacterial; D011498:Protein Precursors / Q000378:metabolism; D021382:Protein Sorting Signals / Q000378:metabolism; D012486:Salmonella typhimurium / Q000032:analysis / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; C035832:hook protein, bacterial flagellum