In vitro transcription initiation from three different Escherichia coli promoters

Abstract
Transcription initiation from .beta.-lactamase, tetracycline resistance and RNA1 promoters, present in plasmid pAT153, were studied employing the abortive initiation technique. Assays appear to be promoter-specific with supercoiled and linear templates. Supercoiling enhances the isomerization rate constant of the open RNA-polymerase-promoter complex formation. Results agree with the in vivo behavior of the corresponding promoters, and show the effect of supercoiling on transcription initiation.