Requirements for the phosphorylation of the Escherichia coli EIIANtr protein in vivo.
The nitrogen-related phosphotransferase system (Ntr-PTS) is a paralogous system working in parallel to the well-known carbohydrate:PTS. In a chain of phosphotransfer reactions, EINtr and NPr (PtsO) deliver phosphoryl groups to the EIIANtr (PtsN) protein. EIIANtr is implicated in important regulatory processes such as the sigmaE-dependent cell envelope stress response and regulation of K+ uptake. Phosphorylation is believed to trigger the output of EIIANtr in these regulations. EIIANtr is encoded within the gene cluster ptsN-yhbJ-ptsO, which is highly conserved in Proteobacteria. In this study, we investigated the phosphorylation of the Escherichia coli EIIANtr protein in vivo by 32P-labeling. We show that EIIANtr is readily phosphorylated in wild-type cells. This phosphorylation occurs at a single site, the histidine 73 in EIIANtr. YhbJ and NPr are dispensable for this phosphorylation. A detailed analysis revealed that both the energy coupling phosphotransferases of the Ntr-PTS as well as the 'sugar'-PTS contribute to the phosphorylation of EIIANtr, suggesting cross talk between both systems.
Zimmer
Björn
B
Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University, Göttingen, Germany.
Hillmann
Antje
A
Görke
Boris
B
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D028044:Phosphate-Binding Proteins; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D016601:RNA-Binding Proteins
D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C502371:NPr protein, E coli; D028044:Phosphate-Binding Proteins; D016601:RNA-Binding Proteins; C524677:YhbJ protein, E coli; D006639:Histidine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C529959:PtsN protein, E coli