Hemin uptake system of Yersinia enterocolitica: similarities with other TonB-dependent systems in gram-negative bacteria.
AUTOR(ES)
Stojiljkovic, I
RESUMO
The hemin receptor HemR of Yersinia enterocolitica was identified as a 78 kDa iron regulated outer membrane protein. Cells devoid of the HemR receptor as well as cells mutated in the tonB gene were unable to take up hemin as an iron source. The hemin uptake operon from Y. enterocolitica was cloned in Escherichia coli K12 and was shown to encode four proteins: HemP (6.5 kDa), HemR (78 kDa), HemS (42 kDa) and HemT (27 kDa). When expressed in E.coli hemA aroB, a plasmid carrying genes for HemP and HemR allowed growth on hemin as a porphyrin source. Presence of genes for HemP, HemR and HemS was necessary to allow E.coli hemA aroB cells to use hemin as an iron source. The nucleotide sequence of the hemR gene and its promoter region was determined and the amino acid sequence of the HemR receptor deduced. HemR has a signal peptide of 28 amino acids and a typical TonB box at its amino-terminus. Upstream of the first gene in the operon (hemP), a well conserved Fur box was found which is in accordance with the iron-regulated expression of HemR.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=557009Documentos Relacionados
- Binding of polymyxin B nonapeptide to gram-negative bacteria.
- Replication of plasmids in gram-negative bacteria.
- Antagonism by gram-negative bacteria to growth of Yersinia enterocolitica in mixed cultures.
- Multidrug efflux pumps of gram-negative bacteria.
- Phospholipase D activity of gram-negative bacteria.