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Roles of the Initial Transcribed Sequence on Productive and Non‐Productive Initiation

Transcription initiation by E. coli RNA polymerase (RNAP) begins with specific binding of RNAP to promoter DNA, the ~100 bp region from the UP‐element (−40 to −60) and farther‐upstream DNA to the initial transcribed region (ITR), extending ~20 bp downstream from the transcription start site (+1). The sequence and length of upstream promoter DNA elements (including −10, −35 and UP elements) are major determinants of the rate of formation of the open promoter complex [1], while the sequence and length of the discriminator element (between the −10 element and the transcription start site (+1) and the length of the ITR are major determinants of the lifetime of the open complex [2,3].