Haem iron-transport system in enterohaemorrhagic Escherichia coli O157

H7

Alfredo Torres, Shelley M. Payne

Research output: Contribution to journalArticle

156 Citations (Scopus)

Abstract

In this study, we identified the iron-transport systems of Escherichia coli O157:H7 strain EDL933. This strain synthesized and transported enterobactin and had a ferric citrate transport system but lacked the ability to produce or use aerobactin. It used haem and haemoglobin, but not transferrin or lactoferrin, as iron sources. We cloned the gene encoding an iron-regulated haem-transport protein and showed that this E. coli haem-utilization gene (chuA) encoded a 69 kDa outer membrane protein that was synthesized in response to iron limitation. Expression of this protein in a laboratory strain of E. coli was sufficient for utilization of haem or haemoglobin as iron sources. Mutation of the chromosomal chuA and tonB genes in E. coli O157:H7 demonstrated that the utilization of haemin and haemoglobin was ChuA- and TonB-dependent. Nucleotide sequence analysis of chuA revealed features characteristic of TonB-dependent, Fur-regulated, outer membrane iron-transport proteins. It was highly homologous to the shuA gene of Shigella dysenteriae and less closely related to hemR of Yersinia enterocolitica and hmuR of Yersinia pestis. A conserved Fur box was identified upstream of the chuA gene, and regulation by Fur was confirmed.

Original languageEnglish (US)
Pages (from-to)825-833
Number of pages9
JournalMolecular Microbiology
Volume23
Issue number4
StatePublished - 1997
Externally publishedYes

Fingerprint

Enterohemorrhagic Escherichia coli
Escherichia coli O157
Heme
Iron
Genes
Hemoglobins
Enterobactin
Shigella dysenteriae
Escherichia coli
Yersinia pestis
Yersinia enterocolitica
Hemin
Lactoferrin
Membrane Transport Proteins
Transferrin
Sequence Analysis
Carrier Proteins
Membrane Proteins
Mutation

ASJC Scopus subject areas

  • Molecular Biology
  • Microbiology

Cite this

Haem iron-transport system in enterohaemorrhagic Escherichia coli O157 : H7. / Torres, Alfredo; Payne, Shelley M.

In: Molecular Microbiology, Vol. 23, No. 4, 1997, p. 825-833.

Research output: Contribution to journalArticle

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