In Vivo Analysis of HPr Reveals a Fructose-Specific Phosphotransferase System That Confers High-Affinity Uptake inStreptomyces coelicolor
| Autor: | Annette Kamionka, Fritz Titgemeyer, Harald Nothaft, Stephan Parche |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Glycerol kinase
Physiology and Metabolism Molecular Sequence Data Mutant macromolecular substances Fructose Phosphocarrier protein Microbiology chemistry.chemical_compound Bacterial Proteins Amino Acid Sequence Codon Phosphoenolpyruvate Sugar Phosphotransferase System Molecular Biology Base Sequence biology Permease Streptomyces coelicolor PEP group translocation biology.organism_classification Fructose transport Carbon Streptomyces carbohydrates (lipids) chemistry Biochemistry biology.protein bacteria |
| Zdroj: | Journal of Bacteriology. 185:929-937 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.185.3.929-937.2003 |
| Popis: | HPr, the histidine-containing phosphocarrier protein of the bacterial phosphotransferase system (PTS), serves multiple functions in carbohydrate uptake and carbon source regulation in low-G+C-content gram-positive bacteria and in gram-negative bacteria. To assess the role of HPr in the high-G+C-content gram-positive organismStreptomyces coelicolor, the encoding gene,ptsH, was deleted. TheptsHmutant BAP1 was impaired in fructose utilization, while growth on other carbon sources was not affected. Uptake assays revealed that BAP1 could not transport appreciable amounts of fructose, while the wild type showed inducible high-affinity fructose transport with an apparentKmof 2 μM. Complementation and reconstitution experiments demonstrated that HPr is indispensable for a fructose-specific PTS activity. Investigation of the putativefruKAgene locus led to identification of the fructose-specific enzyme II permease encoded by thefruAgene. Synthesis of HPr was not specifically enhanced in fructose-grown cells and occurred also in the presence of non-PTS carbon sources. Transcriptional analysis ofptsHrevealed two promoters that are carbon source regulated. In contrast to what happens in other bacteria, glucose repression of glycerol kinase was still operative in aptsHbackground, which suggests that HPr is not involved in general carbon regulation. However, fructose repression of glycerol kinase was lost in BAP1, indicating that the fructose-PTS is required for transduction of the signal. This study provides the first molecular genetic evidence of a physiological role of the PTS inS. coelicolor. |
| Databáze: | OpenAIRE |
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