A hisT::Tn5 mutation affects production of microcins B17, C7, and H47 and colicin V.

A Tn5 insertion decreasing the production of microcin B17 was mapped to 50.2 min on the Escherichia coli chromosome map. Sequence analysis showed that the insertion disrupted hisT, the gene encoding pseudouridine synthase I, a tRNA-modifying enzyme. hisT::Tn5 mutant cells were also shown to be defective for the production of other antibiotic peptides, such as microcin C7, microcin H47, and colicin V.