Pyrimidine, purine and nitrogen control of cytosine deaminase synthesis inEscherichia coliK12. Involvement of theglnLGandpurRgenes in the regulation ofcodAexpression
✍ Scribed by Lennart Andersen; Mogens Kilstrup; Jan Neuhard
- Book ID
- 104780293
- Publisher
- Springer
- Year
- 1989
- Tongue
- English
- Weight
- 415 KB
- Volume
- 152
- Category
- Article
- ISSN
- 0302-8933
No coin nor oath required. For personal study only.
✦ Synopsis
Cytosine deaminase, encoded by the codA gene in Escherichia coli catalyzes the deamination of cytosine to uracil and ammonia. Regulation of codA expression was studied by determining the level of cytosine deaminase in E. coli K 12 grown in various defined media. Addition of either pyrimidine or purine nucleobases to the growth medium caused repressed enzyme levels, whereas growth on a poor nitrogen source such as proline resulted in derepression of cytosine deaminase synthesis. Derepression of codA expression was induced by starvation for either uracil or cytosine nucleotides. Nitrogen control was found to be mediated by the glnLG gene products, and purine repression required a functionalpurR gene product. Studies with strains harbouring multiple mutations affecting both pyrimidine, purine and nitrogen control revealed that the overall regulation of cytosine deaminase synthesis by the different metabolites is cumulative.