Previous Article | Next Article ![]()
Infect. Immun., May 1996, 1724-1735, Vol 64, No. 5
MK Stevens, S Porcella, J Klesney-Tait, S Lumbley, SE Thomas, MV Norgard, JD Radolf and EJ Hansen
Haemophilus ducreyi exhibits a requirement for exogenously supplied heme
for aerobic growth in vitro. Nine of ten wild-type isolates of H. ducreyi
were shown to contain a readily detectable hemoglobin-binding activity.
Spontaneous hemoglobin-binding-negative mutants of two of these wild-type
isolates lost the ability to express an outer membrane protein with an
apparent molecular mass of approximately 100 kDa. Similarly, the single
wild-type isolate that lacked the ability to bind hemoglobin also appeared
to lack expression of this same 100-kDa protein. A monoclonal antibody
(5A9) to this 100-kDa protein was used to identify a recombinant clone
which possessed an H. ducreyi chromosomal fragment containing the gene
encoding the 100-kDa protein; this protein was designated hemoglobin
utilization protein A (HupA). Nucleotide sequence analysis of the hupA gene
revealed that the predicted protein, with a calculated molecular mass of
108 kDa, was similar to TonB-dependent outer membrane proteins of other
bacteria. Increasing the concentration of heme in the growth medium
resulted in decreased expression of the HupA protein. Mutant analysis was
used to prove that the HupA protein was essential for the utilization by H.
ducreyi of both hemoglobin and hemoglobin-haptoglobin as sources of heme in
vitro. In addition, it was found that an isogenic hupA mutant was less
virulent than the wild-type parent strain in the temperature- dependent
rabbit model for dermal lesion production by H. ducreyi.
Copyright © 1996, American Society for Microbiology
A hemoglobin-binding outer membrane protein is involved in virulence expression by Haemophilus ducreyi in an animal model
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9048, USA.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|