Integration and intramolecular transposition of the TnBP3 transposon of Bordetella pertussis in the Escherichia coli K12 cells mutant for the Hpr protein of the phosphoenolpyruvate-dependent phosphotransferase system

Integration of a plasmid carrying the TnBP3 transposon of Bordetella pertus sis into the chromosome of Escherichia coli and transpositions of the integ rated structure within a chromosome in the wild-type and mutant cells ptsH devoid of the major Hpr protein of the phosphoenolpyruvate-dependent phosph otransferase system were studied. When transposed to a new chromosome site, the integrated structure was precisely (or almost precisely) excised from the metY gene sequence, which resulted in restoration of the Met(+) phenoty pe. The integration and transposition events were only observed in the E. c oli cells carrying the ptsH(+) allele. The ptsH mutations inhibited integra tion and intramolecular transposition, which were restored after phenotypic or genetic suppression of the ptsH mutation. The intensity of the processe s studied were suggested to depend on the integrity of a chain that ensures transferring of the phosphoryl residue by proteins of the phosphotransfera se system in E. coli K12.