Isolation of Escherichia coli RNA Polymerase Binding Sites on T5 and T7 DNA: Further Evidence for Sigma-Dependent Recognition of A-T-Rich DNA Sequences

Previous isolation and analysis of E. coli RNA polymerase (EC 2.7.7.6) binding sites on lambda DNA had demonstrated the existence of a sigma-dependent process of recognition of A-T-rich DNA sequences. We have now extended this finding to T5 and T7 DNA and häve provided evidence for the double-strandedness of the isolated binding sites. The possible equation of these sites to the genetically defined promoters is discussed.