Phosphoenolpyruvate: Sugar phosphotransferase systems and sugar metabolism in Brevibacterium flavum.

Abstract

Brevibacteriumflavum mutants defective in the phosphoenolpyruvate (PEP)-dependent glucose phosphotransferase system (PTS) were selected with high frequency by 2-deoxyglucose-resistance. Most of them (DOGr) still had the fructose-PTS and grew not only on fructose but also on glucose like the wild-type strain. A mutant having l/8th the fructose-PTS activity of the wild strain but normal glucose-PTS activity was isolated as a xylitol-resistant mutant. It grew on glucose but not on fructose. The glucose-PTS was active on glucose, glucosamine, 2-deoxyglucose and mannose, and slightly on methyl-a-glucoside and TV-acetylglucosamine, but not on fructose or xylitol. The fructose-PTS acted on fructose and xylitol, and to someextent on glucose but not on glucosamine or 2-deoxyglucose. Mutants unable to grow on glucose (DOGrGlc~)derived from a DOGrmutant were all defective in the fructose-PTS. All revertants able to grow on glucose derived from a DOGrGlc~mutant had the fructose-PTS. The glucokinase activity was about 2/3rds the glucose activity of the fructose-PTS. All the DOGrGlc"mutants had normal levels of glucokinase. One of these mutants grew on maltose and sucrose, which were hydrolyzed to glucose. Thus, glucokinase seems to contribute to the phosphorylation of glucose liberated inside the cell. The fructose-PTS was induced by fructose and repressed by glucose. The glucose repression was not observed in a mutant defective in the glucose-PTS.In Brevibacteriumflavum, an industrial bacterium producing amino acids, glucose is me- 3) The role of glucokinase in glucose metabolism was not revealed. If glucose is phosphorylated solely at the expense of PEP, the theoretical yield in the fermentative production of amino acids synthesized from PEP will be greatly affected. The present paper deals with the derivation of PTS mutants, properties of the individual PTSs and the roles of the PTSs and glucokinase in sugar metabolism.

Identification and application of a different glucose uptake system that functions as an alternative to the phosphotransferase system in Corynebacterium glutamicum

“…The glucose analogue has also been shown to be a toxic substrate for the glucose-PTS of C. glutamicum (Mori and Shiio 1987). If strain SPH2 uptakes glucose exclusively by a different system from the PTS, the strain may exhibit a phenotype of resistance to 2-deoxyglucose.…”

Identification of a second β-glucoside phosphoenolpyruvate : carbohydrate phosphotransferase system in Corynebacterium glutamicum R

“…C. glutamicum R can provide high yields of lactate and succinate from sugar (Inui et al, 2004a;Okino et al, 2008a, b). In C. glutamicum, the general PTS (EI and HPr) as well as glucose-, fructose-and sucrose-specific PTS EIIs (Mori & Shiio, 1987;Dominguez & Lindley, 1996;Kotrba et al, 2001b;Parche et al, 2001;Moon et al, 2005), and additional pts genes (cgR_2922 and cgR_2923 of C. glutamicum R, cg3365 and cg3366 of C. glutamicum ATCC 13032) for unidentified substrates are present. However, a full understanding of the regulatory role of the PTS in C. glutamicum remains elusive.…”

Metabolic Engineering of an ATP-Neutral Embden-Meyerhof-Parnas Pathway in Corynebacterium glutamicum: Growth Restoration by an Adaptive Point Mutation in NADH Dehydrogenase

“…In C. glutamicum, glucose, fructose, and sucrose are imported and phosphorylated by the phosphoenolpyruvate-dependent carbohydrate:phosphotransferase system (PTS) and enter the EMP pathway as glucose-6-phosphate or fructose 1,6-bisphosphate (25,26). As is typical, the EMP pathway yields 2 mol of ATP per mol of glucose in C. glutamicum.…”