L-Glutamine as nitrogen source for Corynebacterium glutamicum: derepression of the AmtR regulon and implications for nitrogen sensing,10.1099/mic.0.04

• ...This is in accordance with the results of reporter gene assays and RNA hybridization experiments, which revealed that transcription of the GOGAT-encoding gltBD operon strictly depends on ammonium limitation (Beckers et al. 2001; Schulz et al. 2001; Silberbach et al. 2005; Rehm et al. 2010b)...
• ...Based on RNA hybridization analyses in combination with various growth conditions, different publications favor ammonium as one molecule, which flags the nitrogen status of C. glutamicum (Nolden et al. 2001b; Müller et al. 2006; Rehm et al. 2010b)...
• ...When ammonium assimilation and L-glutamate production were investigated in more detail by mutant analyses recently (Rehm et al. 2010b), only gdh deletion significantly affected growth and L-glutamate formation with ammonium...
• ...However, in combination with a gltBD deletion, the negative impact of a gdh deletion on growth and on the intracellular L-glutamate pool was even more pronounced (Rehm et al. 2010b)...
• ...Compared to E. coli (for example, see Yan 2007; Kumar and Shimizu 2010), C. glutamicum comprises an about tenfold higher GDH activity (Burkovski 2005; Rehm et al. 2010b) and an at least twofold higher GS activity (Rehm et al. 2010b)...
• ...Compared to E. coli (for example, see Yan 2007; Kumar and Shimizu 2010), C. glutamicum comprises an about tenfold higher GDH activity (Burkovski 2005; Rehm et al. 2010b) and an at least twofold higher GS activity (Rehm et al. 2010b)...
• ...Furthermore, with 100 to 500 mM for L-glutamate and 10 to 50 mM for L-glutamine, extremely high internal pools of these amino acids were already found in the wild type (Nolden et al. 2001b; Rehm et al. 2010b), which might serve as a nitrogen buffer and be beneficial at least for L-glutamate and L-glutamine production...
• ...Previous (Börmann et al. 1992; Börmann-El Kholy et al. 1993; Tesch et al. 1998; Müller et al. 2006) and especially recent studies (Rehm et al. 2010b) of mutant strains showed a high robustness of ammonium assimilation and L-glutamate pool...

Nadine Rehm, et al. Engineering of nitrogen metabolism and its regulation in Corynebacteri...