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Methods to Inhibit Bacterial Pyomelanin Production and Determine the Corresponding Increase in Sensitivity to Oxidative Stress
Published on: August 31, 2015
Factors accelerating pyrimidine production in Deinococcus radiophilus.
Don McPhail1, Man-Kim Cheung, Judith Brown
1School of Life Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK.
Archives of Microbiology
|September 23, 2008
Summary
Deinococcus radiophilus carbamoyl phosphate synthetase assays yielded anomalous results. Aspartate nitrogen may supply glutamine synthesis, bypassing external glutamine.
Area of Science:
- Biochemistry
- Microbiology
- Enzymology
Background:
- The pyrimidine biosynthesis pathway is crucial for cellular function.
- Deinococcus radiophilus is a bacterium known for its radiation resistance.
- Understanding metabolic pathways in extremophiles like D. radiophilus is important.
Purpose of the Study:
- To investigate the pyrimidine synthesizing pathway in Deinococcus radiophilus.
- To characterize the behavior of carbamoyl phosphate synthetase (CPS) in this organism.
- To elucidate the source of nitrogen for glutamine synthesis in CPS assays.
Main Methods:
- Utilized two distinct assay methods for carbamoyl phosphate synthetase: a coupled assay and a direct assay.
- Employed 14C-labeled bicarbonate as a substrate to measure carbon fixation.
- Manipulated substrate composition, specifically aspartate and glutamine, to observe effects on enzyme activity.
Main Results:
- Observed a significant discrepancy in radioactive counts between the coupled and direct CPS assays (direct assay yielded ~5% of coupled).
- Found that omitting glutamine from assay mixtures did not affect radioactive carbon fixation.
- These findings suggest an unusual nitrogen source for glutamine synthesis.
Conclusions:
- Aspartate amino-nitrogen is a potential source for glutamine synthesis via a substrate-channelled pathway to CPS.
- Externally supplied glutamine may not effectively access the CPS binding site in D. radiophilus.
- The results indicate a unique metabolic regulation or enzyme interaction in this bacterium.
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