Nitrogen regulation in Corynebacterium glutamicum: isolation of genes involved and biochemical characterization of corresponding proteins

The regulation of nitrogen assimilation was investigated in the Gram-positi ve actinomycete Corynebacterium glutamicum: Biochemical studies and site-di rected mutagenesis revealed that glutamine synthetase activity is regulated via adenylylation in this organism. The genes encoding the central signal transduction protein P-II (glnB) and the primary nitrogen sensor uridylyltr ansferase (glnD) were isolated and sequenced. Additionally, genes putativel y involved in the degradation of ornithine (ocd) and sarcosine (soxA), ammo nium uptake (amtP) and protein secretion (ftsY, srp) were identified in C. glutamicum. Based on these observations, the mechanism of N regulation in C . glutamicum is similar to that of the Gram-negative Escherichia coli. As d educed from data base searches, the described regulation may also hold true for the important pathogen Mycobacterium glutamicum. (C) 1999 Federation o f European Microbiological Societies. Published by Elsevier Science B.V. Al l rights reserved.