Identification of the N-Terminal Domain of Enzyme I of the Escherichia coli Phosphoenolpyruvate:Sugar Phosphotransferase System Produced by Proteolytic Digestion

ABSTRACT Strain DS988, an Azotobacter vinelandii mutant with a reduced capacity to accumulate poly-β-hydroxybutyrate, was isolated after mini-Tn5 mutagenesis of the UW136 strain. Cloning and nucleotide sequencing of the affected locus revealed a gene homologous to Escherichia coli ptsP which encodes enzyme INtr, a homologue of enzyme I of the phosphoenol pyruvate-sugar phosphotransferase system with an N-terminal domain similar to the N-terminal domain of some NifA proteins. Strain DS988 was unable to grow diazotrophically with 10 mM glucose as a carbon source. Diazotrophic growth on alternative carbon sources such as gluconate was only slightly affected. Glucose uptake, as well as glucose kinase and glucose-6-phosphate-dehydrogenase activities that lead to the synthesis of gluconate-6-phosphate, were not affected by the ptsP mutation. The inability of DS988 to grow diazotrophically in 10 mM glucose was overcome by supplying ammonium or other sources of fixed nitrogen. Acetylene reduction activity but not transcription of the nitrogenase structural gene nifH was shown to be impaired in strain DS988 when it was incubated in 10 mM glucose. The diazotrophic growth defect of DS988 was restored either by increasing the glucose concentration to above 20 mM or by lowering the oxygen concentration. These data suggest that a mutation inptsP leads to a failure in poly-β-hydroxybutyrate metabolism and in the respiratory protection of nitrogenase under carbon-limiting conditions.

Download Full-text

The role of enzyme I in the unmasking of an essential thiol of the membrane-bound enzyme II of the phosphoenolpyruvate-glucose phosphotransferase system of Escherichia coli

Biochimica et Biophysica Acta (BBA) - Biomembranes ◽

10.1016/0005-2736(77)90183-3 ◽

1977 ◽

Vol 469 (2) ◽

pp. 211-215 ◽

Cited By ~ 10

Author(s):

Rosine Haguenauer-Tsapis ◽

Adam Kepes

Keyword(s):

Escherichia Coli ◽

Phosphotransferase System ◽

Membrane Bound ◽

Enzyme I

Download Full-text

A novel phosphoprotein dependent on the bacterial phosphoenolpyruvate–sugar phosphotransferase system

Canadian Journal of Biochemistry and Cell Biology ◽

10.1139/o83-022 ◽

1983 ◽

Vol 61 (2-3) ◽

pp. 150-153 ◽

Cited By ~ 6

Author(s):

E. Bruce Waygood ◽

Roshan L. Mattoo

Keyword(s):

Escherichia Coli ◽

Salmonella Typhimurium ◽

Growth Conditions ◽

Phosphotransferase System ◽

Crude Extracts ◽

Enzyme I ◽

Novel Protein

A protein has been found by isoelectricfocusing and autoradiography in Escherichia coli and Salmonella typhimurium which was phosphorylated by enzyme I and an histidine-containing phosphocarrier protein (HPr) of the phosphoenolpyruvate–sugar phosphotransferase system (PTS). This protein was not factor IIIglc nor was it specifically induced by fructose. Its presence in soluble crude extracts was dependent upon growth conditions; however, the two bacteria had different patterns and amounts in respect to this novel protein. The protein was present in S. typhimurium SB2950 which has an extensive deletion through the pts operon, thus indicating that it must be coded for elsewhere on the genome.

Download Full-text