[Study of phage T7 DNA-dependent RNA-polymerase using GTP analogs. Affinity modification and study of interaction...

Interactions of the bacteriophage T7 DNA-dependent RNA polymerase with three GTP analogs have been studied. All of the three analogs tested contained substituted naphthalenesulphamide groups and were shown to be under appropriate conditions irreversible covalent inhibitors of the enzyme, the modified enzyme possessing fluorescent properties. One of these analogs contained the reactive 2-bromoethyl phosphonate group and was shown to cause the loss of the enzyme affinity for polynucleotide templates. The other two modifiers which contained the azide reactive group did not alter the enzyme-template affinity, the polynucleotide binding leading to a notable increase of the enzyme fluorescence intensity. The latter two modifiers are supposed to be convenient for fluorescent labelling of the active site of RNA polymerase for enzyme-template binding studies.