Integration and Intramolecular Transposition of the TnBP3 Transposon ofBordetella pertussis in the Escherichia coliK12 Cells Mutant for the Hpr Protein of the Phosphoenolpyruvate-Dependent Phosphotransferase System

Integration of a plasmid carrying the TnBP3 transposon of Bordetella pertussisinto the chromosome of Escherichia coliand transpositions of the integrated structure within a chromosome in the wild-type and mutant cells ptsHdevoid of the major Hpr protein of the phosphoenolpyruvate-dependent phosphotransferase system were studied. When transposed to a new chromosome site, the integrated structure was precisely (or almost precisely) excised from the metYgene sequence, which resulted in restoration of the Met⁺phenotype. The integration and transposition events were only observed in the E. colicells carrying the ptsH⁺allele. The ptsHmutations inhibited integration and intramolecular transposition, which were restored after phenotypic or genetic suppression of the ptsHmutation. The intensity of the processes studied were suggested to depend on the integrity of a chain that ensures transferring of the phosphoryl residue by proteins of the phosphotransferase system in E. coliK12.