Requirement of the dephospho-form of enzyme IIANtr for derepression of Escherichia coli K-12 ilvBN expression.
While the proteins of the phosphoenolpyruvate:carbohydrate phosphotransferase system (carbohydrate PTS) have been shown to regulate numerous targets, little such information is available for the nitrogen-metabolic phosphotransferase system (nitrogen-metabolic PTS). To elucidate the physiological role of the nitrogen-metabolic PTS, we carried out phenotype microarray (PM) analysis with Escherichia coli K-12 strain MG1655 deleted for the ptsP gene encoding the first enzyme of the nitrogen-metabolic PTS. Together with the PM data, growth studies revealed that a ptsN (encoding enzyme IIA(Ntr)) mutant became extremely sensitive to leucine-containing peptides (LCPs), while both ptsP (encoding enzyme I(Ntr)) and ptsO (encoding NPr) mutants were more resistant than wild type. The toxicity of LCPs was found to be due to leucine and the dephospho-form of enzyme IIA(Ntr) was found to be necessary to neutralize leucine toxicity. Further studies showed that the dephospho-form of enzyme IIA(Ntr) is required for derepression of the ilvBN operon encoding acetohydroxy acid synthase I catalysing the first step common to the biosynthesis of the branched-chain amino acids.
Lee
Chang-Ro
CR
Laboratory of Macromolecular Interactions, Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea.
Koo
Byoung-Mo
BM
Cho
Seung-Hyon
SH
Kim
Yu-Jung
YJ
Yoon
Mi-Jeong
MJ
Peterkofsky
Alan
A
Seok
Yeong-Jae
YJ
D000095:Acetolactate Synthase / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D050939:Gene Fusion; D017930:Genes, Reporter; D007930:Leucine; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000378:metabolism*; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D001616:beta-Galactosidase / Q000235:genetics
D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D000095:Acetolactate Synthase; C487562:IIA(Ntr) protein, E coli; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D001616:beta-Galactosidase; D007930:Leucine