T7 RNA polymerase: use of limited proteolysis for the study of enzyme's interaction with substrates and inhibitors.

The specific limited trypsinolysis of bacteriophage T7 RNA polymerase (T7RP) was performed in the presence of various components of the polymerase reaction and some GTP-analogs--irreversible inhibitors of the enzyme. The differences in the rate and sites of proteolysis were observed. Basing on the data obtained the role of the N-terminal domain of the T7RP in the interaction with promoter-containing template is proposed.