Release of glucose-mediated catabolite repression due to a defect in the membrane fraction of phosphoenolpyruvate: mannose phosphotransferase system in Pediococcus halophilus |
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Authors: | Keietsu Abe Kinji Uchida |
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Institution: | (1) Soy Sauce Research Laboratory, Kikkoman Corporation, 399 Noda, 278 Noda-shi, Chiba-ken, Japan |
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Abstract: | A spontaneous mutant 9R-4 resistant to 2-deoxyglucose (2DG) was derived from a wild-type strain Pediococcus halophilus I-13. Phosphoenolpyruvate (PEP)-dependent glucose-6-phosphate formation by the permeabilized 9R-4 cells was < 5% of that observed with the parent I-13. In vitro complementation of PEP-dependent 2DG-6-phosphate formation was assayed with combination of the cytoplasmic and membrane fractions prepared from the I-13 and the mutants (9R-4, and X-160 isolated from nature), which were defective in PEP: mannose phosphotransferase system (man:PTS). The defects in man:PTS of both the strain 9R-4 and X-160 were restricted to the membrane fraction (e.g. EIIman), not to the cytoplasmic one. Kinetic studies on the glucose transport with intact cells and iodoacetate-treated cells also supported the presence of two distinct transport systems in this bacterium as follows: (i) The wild-type I-13 possessed a high-affinity man:PTS (K
m=11 M) and a low-affinity proton motive force driven glucose permease (GP) (K
m=170 M). (ii) Both 9R-4 and X-160 had only the low-affinity system (K
m=181 M for 9R-4, 278 M for X-160). In conclusion, a 2DG-induced selective defect in the membrane component (EIIman) of the man:PTS could partially release glucose-mediated catabolite repression but not frutose-mediated catabolite repression in soy pediococci.Abbreviations GCR
glucose-mediated catabolite repression
- FCR
fructose-mediated catabolite repression
- PEP
phosphoenolpyruvate
- man:PTS
phosphoenolpyruvate:mannose phosphotransferase system
- glc:PTS
phosphoenolpyruvate:glucose phosphotransferase system
- GP
glucose permease
- CCCP
carbonylcyanide mchlorophenylhydrazone
- DCCD
N,N -dicyclohexylcarbodiimide
- P
proton motive force
- G-6-P
glucose-6-phosphate
- 2DG
2-deoxyglucose
- IAA
iodoacetic acid
- EIIman
enzyme II component of man:PTS
- EIIIman
enzyme III component of man:PTS
- EIIglc
enzyme II component of glc:PTS
- EIIIglc
enzyme III component of glc:PTS |
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Keywords: | Pediococcus halophilus Membrane Glucose transport Phosphotransferase EnzymeIIman Glucose permease Catabolite repression |
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