Genetics and Regulation of the Major Enzymes of Alanine Synthesis in Escherichia coli
| Autor: | Sok Ho Kim, Barbara L. Schneider, Larry Reitzer |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Physiology and Metabolism
Mutant Biology medicine.disease_cause Microbiology Gene Expression Regulation Enzymologic Transaminase chemistry.chemical_compound Pyruvic Acid Escherichia coli medicine Molecular Biology Gene Transaminases chemistry.chemical_classification Genetics Alanine Mutation Escherichia coli Proteins Gene Expression Regulation Bacterial Molecular biology Carbon Culture Media Enzyme chemistry Biochemistry Pyruvic acid |
| Zdroj: | Journal of Bacteriology. 192:5304-5311 |
| ISSN: | 1098-5530 0021-9193 |
| Popis: | Genetic analysis of alanine synthesis in the model genetic organism Escherichia coli has implicated avtA , the still uncharacterized alaA and alaB genes, and probably other genes. We identified alaA as yfbQ . We then transferred mutations in several transaminase genes into a yfbQ mutant and isolated a mutant that required alanine for optimal growth. For cells grown with carbon sources other than pyruvate, the major alanine-synthesizing transaminases are AvtA, YfbQ (AlaA), and YfdZ (which we designate AlaC). Growth with pyruvate as the carbon source and multicopy suppression suggest that several other transaminases can contribute to alanine synthesis. Expression studies showed that alanine modestly repressed avtA and yfbQ but had no effect on yfdZ . The leucine-responsive regulatory protein (Lrp) mediated control by alanine. We purified YfbQ and YfdZ and showed that both are dimers with K m s for pyruvate within the intracellular range of pyruvate concentration. |
| Databáze: | OpenAIRE |
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