Regulation of Carbon Metabolism in Corynebacterium glutamicum
Annette Arndt and Bernhard J. Eikmanns
from: Corynebacteria: Genomics and Molecular Biology (Edited by: Andreas Burkovski). Caister Academic Press, U.K. (2008)
The amino acid producing Corynebacterium glutamicum grows aerobically on a variety of carbohydrates, organic acids and alcohols as single or combined sources of carbon and energy. Among the substrates metabolized are glucose, L-lactate, acetate and ethanol which all four can also serve as substrates for amino acid production. Based on biochemical and genetic studies, on quantitative determination of metabolic fluxes and/or on genome-based methods such as DNA microarray analyses, this chapter mainly summarizes the present knowledge on the different steps and the regulation of the fundamental pathways in C. glutamicum during growth on glucose, L-lactate, acetate and/or ethanol. It becomes evident that carbon metabolism in this organism is subject to complex regulation at the transcriptional and at the post-transcriptional level. So far, eight transcriptional regulators, i.e., SugR, GntR1, GntR2, AcnR, LldR, RamA, RamB and GlxR and the serine/threonine (Ser/Thr) protein kinase G, phospho-Ser/Thr protein phosphatase and their target protein OdhI have been identified to be involved in the regulation of key enzymes in carbon metabolism, i.e., in the regulation of substrate uptake and activation, glycolysis, tricarboxylic acid (TCA) cycle, glyoxylate cycle and/or gluconeogenesis. Although the molecular mechanisms of transcriptional and post-transcriptional regulation of the enzymes involved in carbon metabolism is not yet completely understood, the recent findings led to a much better understanding of the adaptation of C. glutamicum to a given carbon source at the molecular level read more ...