L-Glutamine metabolism and its regulation in C. glutamicum
Ontology highlight
ABSTRACT: Corynebacterium glutamicum, a gram-positive soil bacterium used for the industrial production of amino acids such as L-glutamate and L-lysine, is able to use a number of different nitrogen sources, such as ammonium, urea, or creatinine. In this communication, we show that L-glutamine serves as an excellent nitrogen source for C. glutamicum and allows similar growth rates in glucose minimal medium as ammonium. A transcriptome comparison revealed a strong induction of the nitrogen starvation response when glutamine was used as nitrogen source. Subsequent growth experiments with a variety of mutants defective in nitrogen metabolism showed that glutamate synthase is crucial for glutamine utilization, while a putative glutaminase is dispensable under the experimental conditions used. The fact that the glutamate synthase encoding gltBD operon is under strict nitrogen control explains the necessity for induction of the nitrogen starvation response. The paradox situation that the nitrogen starvation response is induced although intracellular L-glutamine levels are high has implications on nitrogen sensing. In contrast to other gram-positive and gram-negative bacteria such as Bacillus subtilis, Salmonella typhimurium, and Klebsiella pneumoniae, a drop in glutamine concentration obviously does not serve as a nitrogen starvation signal in C. glutamicum. Three biological replicates were performed. To analyse how L-glutamine influences global gene expression when used as sole nitrogen source instead of ammonium, DNA microarray analyses were performed. For this purpose RNA was isolated from exponentially growing cells cultivated in CgXII medium containing glucose as carbon source and either L-glutamine or ammonium sulphate as nitrogen source.
ORGANISM(S): Corynebacterium glutamicum ATCC 13032
SUBMITTER: Andreas Burkovski
PROVIDER: E-GEOD-19779 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
ACCESS DATA