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Tight leash on ammonia


16 Aug 2012

In low-GC Gram-positive bacteria four regulators, GlnR, TnrA, GltC and CodY, manage the transcriptional control of the enzymes involved in central nitrogen metabolism. Based on an extensive analysis of the genomes of all species belonging the class Bacilli, which includes well-known families such as Bacillaceae, Lactobacillaceae and Staphylococcaceae, Tom Groot Kormelink (Kluyver Centre for Genomics of Industrial Fermentation) and colleagues found that the GlnR regulon is the most constant of the four. Furthermore, GlnR appears unaffected by the absence/presence of the other three regulators. According to the authors, constraining the import of ammonia- and amino-containing compounds is primarily regulated by GlnR, as is the production of intracellular ammonia. Tight control of ammonia levels is important to limit futile cycling by diffusion of ammonia out of the cell, which fits with the proposed role of GlnR, the authors state.

Groot Kormelink T, Koenders E, Hagemeijer Y, Overmars L, Siezen RJ, de Vos WM, Francke C
Comparative genome analysis of central nitrogen metabolism and its control by GlnR in the class Bacilli.
BMC Genomics 2012, 13:191

By: Esther Thole