Contacts between Escherichia coli RNA polymerase and an early promoter of phage T7.

Abstract

Specific contacts between the E. coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) and the phosphates and purine bases of the A3 promoter of phage T7 cluster into 3 regions located approximately 10, 16 and 35 base pairs before the RNA initiation site. Two of these contain nucleotide sequences that are fairly conserved among many promoters, known as the Pribnow box and -35 region homologies; the third, just upstream from the Pribnow box, is not conserved. The polymerase binds preferentially to the coding strand and for the most part touches only 1 face of the DNA helix.