title: Cloning and characterization of the exbB-exbD-tonB locus of Pasteurella haemolytica A1.
abstract: A recombinant plasmid (pMG1) carrying Pasteurella haemolytica A1 DNA which complements a tonB mutation of Escherichia coli has been isolated. E. coli tonB metE which carries pMG1 exhibits growth kinetics in the presence of vitamin B12 similar to that of the wild-type host. In addition, the complemented E. coli is susceptible to killing by bacteriophage phi 80 and colicin B. Analysis of the nucleotide sequence in the complementing DNA showed that it codes for three genes in the order of exbB-exbD-tonB. This genetic organization has been reported in Haemophilus influenzae, H. ducreyi, Pseudomonas putida and Vibrio cholerae, and may represent a separate lineage of evolution from that of the Enterobacteriaceae in which tonB is unlinked with the accessory genes exbB and exbD. A comparison of the DNA flanking the exbB-exbD-tonB locus in P. haemolytica A1 and H. influenzae showed that the flanking regions are completely different between the two organisms.
authors.affiliation: Department of Microbiology, University of Guelph, Ontario, Canada.
authors.forename: M R
authors.initials: MR
authors.lastname: Graham
authors.forename: R Y
authors.initials: RY
authors.lastname: Lo
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins; D016978:Mannheimia haemolytica / Q000235:genetics*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids; D011994:Recombinant Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D014805:Vitamin B 12 / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C052874:ExbB protein, E coli; D008565:Membrane Proteins; D011994:Recombinant Proteins; C057616:tonB protein, Bacteria; C489181:tonB protein, E coli; C489182:tonB protein, Haemophilus influenzae; C060790:exbD protein, E coli; D014805:Vitamin B 12