A mutant RNA polymerase that forms unusual open promoter complexes

Konstantin Severinov, Seth A. Darst

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


We describe a mutant F. Escherichia coli RNA polymerase (RNAP) that forms stable open promoter complexes even at -20°C but with a shortened melted region that extends downstream to only position -7. In the presence of initiating transcription substrates, the mutant RNAP undergoes a temperature- dependent isomerization, resulting in a promoter complex that is indistinguishable from the wild-type RNAP-promoter complex, with the melted region extended downstream to position +4. We propose that the open complex formed by the mutant RNAP represents an intermediate on the normal promoter- opening pathway and that our results support earlier findings that initial promoter opening occurs in the upstream region of the -10 promoter consensus element and subsequently extends downstream to encompass the transcription start site.

Original languageEnglish (US)
Pages (from-to)13481-13486
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number25
StatePublished - Dec 9 1997

All Science Journal Classification (ASJC) codes

  • General


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