Requirement of the dephospho‐form of enzyme IIANtr for derepression of Escherichia coli K‐12 ilvBN expression

• Published in: Molecular microbiology 2005-10, Vol.58 (1), p.334-344
• Main Authors: Lee, Chang‐Ro, Koo, Byoung‐Mo, Cho, Seung‐Hyon, Kim, Yu‐Jung, Yoon, Mi‐Jeong, Peterkofsky, Alan, Seok, Yeong‐Jae
• Format: Article
• Language: English
• Subjects: Acetolactate Synthase - genetics; Acetolactate Synthase - metabolism; Bacteriology; beta-Galactosidase - genetics; Biological and medical sciences; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Deletion; Gene Expression Regulation, Bacterial; Gene Fusion; Genes, Reporter; Leucine; Microbiology; Miscellaneous; Oligonucleotide Array Sequence Analysis; Operon; Phosphoenolpyruvate Sugar Phosphotransferase System - metabolism; RNA, Bacterial - analysis; RNA, Messenger - analysis
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2005.04834.x

Summary 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 IIANtr) mutant became extremely sensitive to leucine‐containing peptides (LCPs), while both ptsP (encoding enzyme INtr) 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 IIANtr was found to be necessary to neutralize leucine toxicity. Further studies showed that the dephospho‐form of enzyme IIANtr 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.