title: Identification of the znuA-encoded periplasmic zinc transport protein of Haemophilus ducreyi.
abstract: The znuA gene of Haemophilus ducreyi encodes a 32-kDa (mature) protein that has homology to both the ZnuA protein of Escherichia coli and the Pzp1 protein of H. influenzae; both of these latter proteins are members of a growing family of prokaryotic zinc transporters. Inactivation of the H. ducreyi 35000 znuA gene by insertional mutagenesis resulted in a mutant that grew more slowly than the wild-type parent strain in vitro unless ZnCl(2) was provided at a final concentration of 100 microM. Other cations tested did not restore growth of this H. ducreyi mutant to wild-type levels. The H. ducreyi ZnuA protein was localized to the periplasm, where it is believed to function as the binding component of a zinc transport system. Complementation of the znuA mutation with the wild-type H. ducreyi znuA gene provided in trans restored the ability of this H. ducreyi mutant to grow normally in the absence of exogenously added ZnCl2. The wild-type H. ducreyi znuA gene was also able to complement a H. influenzae pzp1 mutation. The H. ducreyi znuA isogenic mutant exhibited significantly decreased virulence (P = 0.0001) when tested in the temperature-dependent rabbit model for experimental chancroid. This decreased virulence was not observed when the znuA mutant was complemented with the wild-type H. ducreyi znuA gene provided in trans.
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9048, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Lewis
authors.forename: J
authors.initials: J
authors.lastname: Klesney-Tait
authors.forename: S R
authors.initials: SR
authors.lastname: Lumbley
authors.forename: C K
authors.initials: CK
authors.lastname: Ward
authors.forename: J L
authors.initials: JL
authors.lastname: Latimer
authors.forename: C A
authors.initials: CA
authors.lastname: Ison
authors.forename: E J
authors.initials: EJ
authors.lastname: Hansen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis*; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006191:Haemophilus ducreyi / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D011817:Rabbits; D014774:Virulence; D015032:Zinc / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D015032:Zinc