YeeI, a novel protein involved in modulation of the activity of the glucose-phosphotransferase system in Escherichia coli K-12.
The membrane-bound protein EIICB(Glc) encoded by the ptsG gene is the major glucose transporter in Escherichia coli. This protein is part of the phosphoenolpyruvate:glucose-phosphotransferase system, a very important transport and signal transduction system in bacteria. The regulation of ptsG expression is very complex. Among others, two major regulators, the repressor Mlc and the cyclic AMP-cyclic AMP receptor protein activator complex, have been identified. Here we report identification of a novel protein, YeeI, that is involved in the regulation of ptsG by interacting with Mlc. Mutants with reduced activity of the glucose-phosphotransferase system were isolated by transposon mutagenesis. One class of mutations was located in the open reading frame yeeI at 44.1 min on the E. coli K-12 chromosome. The yeeI mutants exhibited increased generation times during growth on glucose, reduced transport of methyl-alpha-d-glucopyranoside, a substrate of EIICB(Glc), reduced induction of a ptsG-lacZ operon fusion, and reduced catabolite repression in lactose/glucose diauxic growth experiments. These observations were the result of decreased ptsG expression and a decrease in the amount of EIICB(Glc). In contrast, overexpression of yeeI resulted in higher expression of ptsG, of a ptsG-lacZ operon fusion, and of the autoregulated dgsA gene. The effect of a yeeI mutation could be suppressed by introducing a dgsA deletion, implying that the two proteins belong to the same signal transduction pathway and that Mlc is epistatic to YeeI. By measuring the surface plasmon resonance, we found that YeeI (proposed gene designation, mtfA) directly interacts with Mlc with high affinity.
Becker
Ann-Katrin
AK
Department of Biology and Chemistry, University of Osnabrück, D-49069 Osnabrück, Germany.
Zeppenfeld
Tim
T
Staab
Ariane
A
Seitz
Sabine
S
Boos
Winfried
W
Morita
Teppei
T
Aiba
Hiroji
H
Mahr
Kerstin
K
Titgemeyer
Fritz
F
Jahreis
Knut
K
D002876:Chromosomes, Bacterial / Q000235:genetics; D003470:Culture Media; D048168:Escherichia coli K12 / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005947:Glucose; D007785:Lactose; D009154:Mutation; D016366:Open Reading Frames; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism
D003470:Culture Media; D029968:Escherichia coli Proteins; C111065:Mlc protein, E coli; D012097:Repressor Proteins; C512679:YeeI protein, E coli; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C031629:phosphoenolpyruvate-glucose phosphotransferase; D005947:Glucose; D007785:Lactose