Open AccessRequirements for the phosphorylation of the Escherichia coli EIIA Ntr protein in vivo
Author(s) -
Zimmer Björn,
Hillmann Antje,
Görke Boris
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01262.x
Subject(s) - phosphorylation , pep group translocation , escherichia coli , protein phosphorylation , biochemistry , phosphotransferase , biology , histidine , microbiology and biotechnology , chemistry , gene , protein kinase a , amino acid
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, EI Ntr and NPr (PtsO) deliver phosphoryl groups to the EIIA Ntr (PtsN) protein. EIIA Ntr is implicated in important regulatory processes such as the σ E ‐dependent cell envelope stress response and regulation of K + uptake. Phosphorylation is believed to trigger the output of EIIA Ntr in these regulations. EIIA Ntr 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 EIIA Ntr protein in vivo by 32 P‐labeling. We show that EIIA Ntr is readily phosphorylated in wild‐type cells. This phosphorylation occurs at a single site, the histidine 73 in EIIA Ntr . 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 EIIA Ntr , suggesting cross talk between both systems.