Mechanism of increased respiration in an H+-ATPase-defective mutant of Corynebacterium glutamicum

• Published in: Journal of bioscience and bioengineering Vol. 113; no. 4; pp. 467 - 473
• Main Authors: Sawada, Kazunori, Kato, Yui, Imai, Keita, Li, Liyuan, Wada, Masaru, Matsushita, Kazunobu, Yokota, Atsushi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2012; Elsevier
• Subjects: ATPase; Biological and medical sciences; Biotechnology; coping strategies; Corynebacterium glutamicum; Corynebacterium glutamicum - enzymology; Corynebacterium glutamicum - genetics; Corynebacterium glutamicum - metabolism; Cytochromes; DNA microarrays; Electron Transport - genetics; Energy deficiency; Energy metabolism; enzyme activity; Escherichia coli; Fermentation; fermenters; Fundamental and applied biological sciences. Psychology; gene expression regulation; Gene Expression Regulation, Bacterial; glucose; H+-ATPase defect; H-transporting ATP synthase; malate dehydrogenase; microarray technology; mutants; Mutation; NAD (coenzyme); NAD - metabolism; NADH reoxidation; Oxidoreductases - metabolism; point mutation; proton-motive force; Proton-Translocating ATPases - genetics; quantitative polymerase chain reaction; respiration rate; Respiratory chain; respiratory rate; succinate dehydrogenase (quinone); transcription (genetics); H+-ATPase defect; Respiratory chain; Energy metabolism; Energy deficiency; Corynebacterium glutamicum; NADH reoxidation; ATPase defect; Enzyme; Deficiency; H; transporting ATP synthase; Mechanism; NADH; Bacteria; Hydrolases; Actinomycetes; Corynebacteriaceae; Mutation; Respiration
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2011.11.021

We previously reported that a spontaneous H+-ATPase-defective mutant of Corynebacterium glutamicum, F172-8, derived from C. glutamicum ATCC 14067, showed enhanced glucose consumption and respiration rates. To investigate the genome-based mechanism of enhanced respiration rate in such C. glutamicum mutants, A-1, an H+-ATPase-defective mutant derived from C. glutamicum ATCC 13032, which harbors the same point mutation as F172-8, was used in this study. A-1 showed similar fermentation profiles to F172-8 when cultured in a jar fermentor. Enzyme activity measurements, quantitative real-time PCR, and DNA microarray analysis suggested that A-1 enhanced malate:quinone oxidoreductase/malate dehydrogenase and l-lactate dehydrogenase/NAD+-dependent-lactate dehydrogenase coupling reactions, but not NADH dehydrogenase-II, for reoxidation of the excess NADH arising from enhanced glucose consumption. A-1 also up-regulated succinate dehydrogenase, which may result in the relief of excess proton-motive force (pmf) in the H+-ATPase mutant. In addition, the transcriptional level of cytochrome bd oxidase, but not cytochrome bc1-aa3, also increased, which may help prevent the excess pmf generation caused by enhanced respiration. These results indicate that C. glutamicum possesses intriguing strategies for coping with NADH over-accumulation. Furthermore, these mechanisms are different from those in Escherichia coli, even though the two species use similar strategies to prevent excess pmf generation.