Lactobacillus casei 64H Contains a Phosphoenolpyruvate-Dependent Phosphotransferase System for Uptake of Galactose, as Confirmed by Analysis of ptsH and Different gal Mutants
| Autor: | Petra Ehrenreich, Carl-Alfred Alpert, Ulrike Siebers, Katja Bettenbrock |
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| Rok vydání: | 1999 |
| Předmět: |
Lactobacillus casei
Physiology and Metabolism Biological Transport Active Mannose Lactose Biology Microbiology chemistry.chemical_compound Bacterial Proteins Phosphoenolpyruvate Sugar Phosphotransferase System Molecular Biology Galactose Fructose PEP group translocation biology.organism_classification Leloir pathway Kinetics Lacticaseibacillus casei Phenotype chemistry Biochemistry Genes Bacterial Mutation Tagatose |
| Zdroj: | Journal of Bacteriology. 181:225-230 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.181.1.225-230.1999 |
| Popis: | Galactose metabolism in Lactobacillus casei 64H was analyzed by genetic and biochemical methods. Mutants with defects in ptsH , galK , or the tagatose 6-phosphate pathway were isolated either by positive selection using 2-deoxyglucose or 2-deoxygalactose or by an enrichment procedure with streptozotocin. ptsH mutations abolish growth on lactose, cellobiose, N -acetylglucosamine, mannose, fructose, mannitol, glucitol, and ribitol, while growth on galactose continues at a reduced rate. Growth on galactose is also reduced, but not abolished, in galK mutants. A mutation in galK in combination with a mutation in the tagatose 6-phosphate pathway results in sensitivity to galactose and lactose, while a galK mutation in combination with a mutation in ptsH completely abolishes galactose metabolism. Transport assays, in vitro phosphorylation assays, and thin-layer chromatography of intermediates of galactose metabolism also indicate the functioning of a permease/Leloir pathway and a phosphoenolpyruvate-dependent phosphotransferase system (PTS)/tagatose 6-phosphate pathway. The galactose-PTS is induced by growth on either galactose or lactose, but the induction kinetics for the two substrates are different. |
| Databáze: | OpenAIRE |
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