Genetics and regulation of heme iron transport in Shigella dysenteriae and detection of an analogous system in Escherichia coli O157:H7
| Autor: | Melody Mills, Shelley M. Payne |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
DNA
Bacterial Shigella dysenteriae Iron Restriction Mapping Mutant Heme medicine.disease_cause Microbiology Insertional mutagenesis chemistry.chemical_compound Bacterial Proteins Sequence Homology Nucleic Acid Escherichia coli medicine Cloning Molecular Molecular Biology biology Escherichia coli Proteins Membrane Proteins Biological Transport biology.organism_classification Molecular biology Heme transport Mutagenesis Insertional chemistry Biochemistry Genes Bacterial Bacterial outer membrane Protein Binding Research Article Hemin |
| Zdroj: | Journal of Bacteriology. 177:3004-3009 |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | Shigella species can use heme as the sole source of iron. In this work, the heme utilization locus of Shigella dysenteriae was cloned and characterized. A cosmid bank of S. dysenteriae serotype 1 DNA was constructed in an Escherichia coli siderophore synthesis mutant incapable of heme transport. A recombinant clone, pSHU12, carrying the heme utilization system of S. dysenteriae was isolated by screening on iron-poor medium supplemented with hemin. Transposon insertional mutagenesis and subcloning identified the region of DNA in pSHU12 responsible for the phenotype of heme utilization. Minicell analysis indicated that a 70-kDa protein encoded by this region was sufficient to allow heme utilization in E. coli. Synthesis of this protein, designated Shu (Shigella heme uptake), was induced by iron limitation. The 70-kDa protein is located in the outer membrane and binds heme, suggesting it is the S. dysenteriae heme receptor. Heme iron uptake was found to be TonB dependent in E. coli. Transformation of an E. coli hemA mutant with the heme utilization subclone, pSHU262, showed that heme could serve as a source of porphyrin as well as iron, indicating that the entire heme molecule is transported into the bacterial cell. DNA sequences homologous to shu were detected in strains of S. dysenteriae serotype 1 and E. coli O157:H7. |
| Databáze: | OpenAIRE |
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