Purification and properties of a bacteriophage T5-modified form of Escherichia coli RNA polymerase.

A modified form of Escherichia coli RNA polymerase that contains one of the three T5-specific polypeptides known to interact with the host enzyme was purified from bacteriophage T5-infected cells. The properties of this T5-modified enzyme appeared identical to those of the RNA polymerase derived from uninfected non-colicinogenic cells and to a fully active enzyme isolated from T5-infected ColIb+ cells after the limited in vivo transcription of T5 genes allowed by the plasmid had ceased.