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#promoter recognition

3 public questions tagged with this topic.

Transcription in Prokaryotes

σ70 region 2 primarily recognizes

Sigma70 polypeptide organized into four conserved regions comprising helical domains. Region 2, particularly subregion 2.3-2.4, responsible for recognition and melting of -10 Pribnow box element. Crystal structures show aromatic residues tryptophan from region 2 intercalate DNA, flipping adenine at -11 and thymine at -7 into protein pockets stabilizing unwound transcription bubble. Region 4.2 recognizes -35, region 1 autoinhibits DNA binding. Mutations within region 2 abolish -10 specific binding while leaving -35 interaction intact, demonstrating modular mapping. Hence region 2 primarily conf

Ref: Lodish Chapter 8: σ70 region 2 recognizes -10 element Pribnow box; Alberts Chapter 6 Sigma domain structure region mapping

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Transcription in Prokaryotes

UP element is recognized by

UP element is AT-rich sequence located approximately -40 to -60 upstream of transcription start site, found in strong rRNA and tRNA promoters. Crystallographic studies show C-terminal domain of α subunit, α-CTD connected via flexible linker, contains helix-hairpin motif binding minor groove of UP element AT tracts, providing additional anchoring energy independent of sigma -10 and -35 contacts. Interaction can enhance transcription up to thirty fold. β, σ70, β', ω subunits do not directly contact UP. Presence explains why some promoters lacking perfect consensus still strong due to extra α-CTD

Ref: Ross et al. Science 1993 UP element α-CTD interaction; Alberts Chapter 6: UP recognized by α-CTD domain structure

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