A mutated PtsG, the glucose transporter, allows uptake of D-ribose

Cited 36 time in webofscience Cited 0 time in scopus
  • Hit : 262
  • Download : 0
Mutations arose from an Escherichia coli strain defective in the high (Rbs/ribose) and low (Als/allose and Xyl/xylose) affinity D-ribose transporters, which allow cells to grow on D-ribose. Genetic tagging and mapping of the mutations revealed that two loci in the E. coli linkage map are involved in creating a novel ribose transport mechanism. One mutation was found in ptsG, the glucose-specific transporter of phosphoenolpyruvate:carbohydrate phosphotransferase system and the other in mlc, recently reported to be involved in the regulation of ptsG. Five different mutations in ptsG were characterized, whose growth on D-ribose medium was about 80% that of the high affinity system (Rbs(+)). Two of them were found in the predicted periplasmic loops, whereas three others are in the transmembrane region. Ribose uptakes in the mutants, competitively inhibited by D-glucose, D-xylose, or D-allose, were much lower than that of the high affinity transporter but higher than those of the Als and Xyl systems. Further analyses of the mutants revealed that the rbsK (ribokinase) and rbsD (function unknown) genes are involved in the ribose transport through PtsG, indicating that the phosphorylation of ribose is not mediated by PtsG and that some unknown metabolic function mediated by RbsD is-required. It was also found that D-xylose, another sugar not involved in phosphorylation, was efficiently transported through the wild-type or mutant PtsG in mlc-negative background, The efficiencies of xylose add glucose transports are variable in the PtsG mutants, depending on their locations, either in the periplasm or in the membrane. In an extreme case of the transmembrane change (I283T), xylose transport is virtually abolished, indicating that the residue is directly involved in determining sugar specificity. We propose that there are at least two domains for substrate specificity in PtsG with slightly altered recognition properties.
Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Issue Date
1999-05
Language
English
Article Type
Article
Keywords

ESCHERICHIA-COLI K-12; TRANSCRIPTIONAL ACTIVATOR; PHOSPHOTRANSFERASE SYSTEM; PHOSPHORYLATION; GENE; EXPRESSION; CLONING; OPERON; OVEREXPRESSION; PURIFICATION

Citation

JOURNAL OF BIOLOGICAL CHEMISTRY, v.274, no.20, pp.14006 - 14011

ISSN
0021-9258
URI
http://hdl.handle.net/10203/77966
Appears in Collection
BS-Journal Papers(저널논문)
Files in This Item
There are no files associated with this item.
This item is cited by other documents in WoS
⊙ Detail Information in WoSⓡ Click to see webofscience_button
⊙ Cited 36 items in WoS Click to see citing articles in records_button

qr_code

  • mendeley

    citeulike


rss_1.0 rss_2.0 atom_1.0