The iron superoxide dismutase of Legionella pneumophila is essential for viability
| Autor: | J W Wilson, A B Sadosky, Howard A. Shuman, H M Steinman |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Paraquat
Recombinant Fusion Proteins Molecular Sequence Data Mutant Biology medicine.disease_cause Microbiology Aconitase Legionella pneumophila Superoxide dismutase Open Reading Frames chemistry.chemical_compound Bacterial Proteins medicine Amino Acid Sequence Cloning Molecular Molecular Biology Escherichia coli Alleles Aconitate Hydratase Base Sequence Superoxide Dismutase Drug Resistance Microbial Sequence Analysis DNA Periplasmic space biology.organism_classification Diploidy Molecular biology Mutagenesis Insertional Lac Operon chemistry Genes Bacterial Essential gene biology.protein Genes Lethal Research Article |
| Zdroj: | Journal of Bacteriology. 176:3790-3799 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.176.12.3790-3799.1994 |
| Popis: | Legionella pneumophila, the causative agent of Legionnaires' disease, contains two superoxide dismutases (SODs), a cytoplasmic iron enzyme (FeSOD) and a periplasmic copper-zinc SOD. To study the role of the FeSOD in L. pneumophila, the cloned FeSOD gene (sodB) was inactivated with Tn903dIIlacZ, forming a sodB::lacZ gene fusion. By using this fusion, expression of sodB was shown to be unaffected by a variety of conditions, including several that influence sod expression in Escherichia coli: aeration, oxidants, the redox cycling compound paraquat, manipulation of iron levels in the medium, and the stage of growth. A reproducible twofold decrease in sodB expression was found during growth on agar medium containing charcoal, a potential scavenger of oxyradicals, in comparison with growth on the same medium without charcoal. No induction was seen during growth in human macrophages. Additional copies of sodB+ in trans increased resistance to paraquat. Construction of a sodB mutant was attempted by allelic exchange of the sodB::lacZ fusion with the chromosomal copy of sodB. The mutant could not be isolated, and the allelic exchange was possible only if wild-type sodB was present in trans. These results indicate that the periplasmic copper-zinc SOD cannot replace the FeSOD. The data strongly suggest that sodB is an essential gene and that FeSOD is required for the viability of L. pneumophila. In contrast, Sod- mutants of E. coli and Streptococcus mutans grow aerobically and SOD is not required for viability in these species. |
| Databáze: | OpenAIRE |
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