[Repression of the enzyme inducible syntheses in Escherichia coli K12 mutant with a deleted ptsH gene].

The genome of lambda phage with thermosensitive repressor was integrated into the pts region of the E. coli chromosome. Such a lysogenic culture behaves as a pts mutant at 30 degrees. Heating of cells of this strain leads to the induction of lambda prophage and formation of deletions in the pts region. A mutant with a deletion covering ptsH gene was isolated after prophage induction. The deletion nature of pts mutation was confirmed in genetic and biochemical experiments. It was shown that the deletion is small and does not involve ptsI and lig genes. The isolated deltaptsH mutant possesses all characteristics of pts mutants: pleiotropic impairment of transport and utilization of a number of carbohydrates, repression of the enzyme inducible synthesis and resistance to catabolite repression with glucose. These data (together with earlier ones) allow us to conclude that the phosphorylated form of HPr is involved (in direct of indirect manner/ in activation of DNA transcription.