Identification of an outer membrane protein involved in utilization of hemoglobin-haptoglobin complexes by nontypeable Haemophilus influenzae.
AUTOR(ES)
Maciver, I
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=174284Documentos Relacionados
- Detection of Phase Variation in Expression of Proteins Involved in Hemoglobin and Hemoglobin-Haptoglobin Binding by Nontypeable Haemophilus influenzae
- Role of CCAA Nucleotide Repeats in Regulation of Hemoglobin and Hemoglobin-Haptoglobin Binding Protein Genes of Haemophilus influenzae
- Ability of Vibrio vulnificus to obtain iron from hemoglobin-haptoglobin complexes.
- Transport of Intact Porphyrin by HpuAB, the Hemoglobin-Haptoglobin Utilization System of Neisseria meningitidis
- Cellular immunity to the P6 outer membrane protein of nontypeable Haemophilus influenzae.
