Identification of an outer membrane protein involved in utilization of hemoglobin-haptoglobin complexes by nontypeable Haemophilus influenzae

Isobel Maciver, Jo L. Latimer, H. H. Liem, Ursula Muller-Eberhard, Zbynek Hrkal, Eric J. Hansen

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

A recombinant plasmid containing a 6.5-kb fragment of nontypeable Haemophilus influenzae (NTHI) chromosomal DNA was shown to confer a hemoglobin-haptoglobin-binding phenotype on Escherichia coli. Use of a mini- Tn10kan transposon for random insertion mutagenesis of this recombinant plasmid allowed localization of the NTHI DNA responsible for this hemoglobin- haptoglobin-binding phenotype to a 3.5-kb PstI-XhoI fragment within the 6.5- kb NTHI DNA insert. When this mutagenized NTHI DNA fragment was used to transform the wild-type NTHI strain, the resultant kanamycin-resistant mutant exhibited significantly decreased abilities to bind hemoglobin-haptoglobin and utilize it as a source of heme for aerobic growth in vitro. This mutant also lacked expression of a 115-kDa outer membrane protein that was present in the wild-type parent strain. Transformation of this mutant with wild-type NTHI chromosomal DNA restored the abilities to bind and utilize hemoglobin- haptoglobin and to express the 115-kDa outer membrane protein. Nucleotide sequence analysis of the relevant NTHI DNA revealed the presence of a gene, designated hhuA, that encoded a predicted 117,145-Da protein. The HhuA protein exhibited features typical of a TonB-dependent outer membrane receptor and had significant identity with the hemoglobin receptors of both Haemophilus ducreyi and Neisseria meningitidis.

Original languageEnglish (US)
Pages (from-to)3703-3712
Number of pages10
JournalInfection and immunity
Volume64
Issue number9
StatePublished - Sep 22 1996

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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    Maciver, I., Latimer, J. L., Liem, H. H., Muller-Eberhard, U., Hrkal, Z., & Hansen, E. J. (1996). Identification of an outer membrane protein involved in utilization of hemoglobin-haptoglobin complexes by nontypeable Haemophilus influenzae. Infection and immunity, 64(9), 3703-3712.