Novel proteins of the phosphotransferase system encoded within the rpoN operon of Escherichia coli: Enzyme IIANtr affects growth on organic nitrogen and the conditional lethality of an erats mutant

Bradford S. Powell, Donald L. Court, Toshifumi Inada, Yoshikazu Nakamura, Valerie Michotey, Xuewen Cui, Aiala Reizer, Milton H. Saier, Jonathan Reizer

Research output: Contribution to journalArticle

177 Citations (Scopus)

Abstract

Two rpoN-linked ΔTn10-kan insertions suppress the conditionally lethal erats allele. One truncates rpoN while the second disrupts another gene (ptsN) in the rpoN operon and does not affect classical nitrogen regulation. Neither alter expression of era indicating that suppression is post-translational. Plasmid clones of ptsN prevent suppression by either disruption mutation indicating that this gene is important for lethality caused by erats. rpoN and six neighboring genes were sequenced and compared with sequences in the database. Two of these genes encode proteins homologous to Enzyme IIAFru and HPr of the phosphoenolpyruvate:sugar phosphotransferase system. We designate these proteins IIANtr (ptsN) and NPr (npr). Purified IIANtr and NPr exchange phosphate appropriately with Enzyme I, HPr, and Enzyme HA proteins of the phosphoenolpyruvate: sugar phosphotransferase system. Several sugars and tricarboxylic acid cycle intermediates inhibited growth of the ptsN disruption mutant on medium containing an amino acid or nucleoside base as a combined source of nitrogen, carbon, and energy. This growth inhibition was relieved by supplying the ptsN gene or ammonium salts but was not aleviated by altering levels of exogenously supplied cAMP. These results support our previous proposal of a novel mechanism linking carbon and nitrogen assimilation and relates IIANtr to the unknown process regulated by the essential GTPase Era.

Original languageEnglish
Pages (from-to)4822-4839
Number of pages18
JournalJournal of Biological Chemistry
Volume270
Issue number9
DOIs
Publication statusPublished - 1995 Mar 3
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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