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Salmonella typhimurium mutants lacking NAD pyrophosphatase
U E Park1, J R Roth, B M Olivera
1Department of Biology, University of Utah, Salt Lake City 84112.
Journal of Bacteriology
|August 1, 1988
Summary
Salmonella typhimurium utilizes exogenous nicotinamide adenine dinucleotide (NAD) as a nutrient source. Researchers identified mutants unable to break down NAD, revealing a new gene locus involved in this essential metabolic pathway.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Salmonella typhimurium can utilize exogenous nicotinamide adenine dinucleotide (NAD) as a source for both purine and pyridine.
- The initial step in NAD assimilation involves breakdown by NAD pyrophosphatase.
Purpose of the Study:
- To isolate and characterize Salmonella typhimurium mutants deficient in NAD pyrophosphatase activity.
- To identify the genetic locus responsible for NAD pyrophosphatase activity.
Main Methods:
- Isolation of S. typhimurium mutants unable to utilize exogenous NAD as a purine source.
- Genetic mapping of mutations to identify the responsible locus.
Main Results:
- Mutants lacking NAD pyrophosphatase activity were successfully isolated.
- These mutants failed to use exogenous NAD as a purine source.
- The mutations were mapped to a novel locus, pnuE, on the Salmonella chromosome.
Conclusions:
- NAD pyrophosphatase is essential for the assimilation of exogenous NAD in Salmonella typhimurium.
- The pnuE locus is critical for NAD pyrophosphatase function and NAD salvage pathway.