Transcription Factor B Contacts Promoter DNA Near the Transcription Start Site of the Archaeal Transcription Initiation Complex

摘要: Transcription initiation in all three domains of life requires the assembly large multiprotein complexes at DNA promoters before RNA polymerase (RNAP)-catalyzed transcript synthesis. Core RNAP subunits show homology among life, and recent structural information supports this homology. General transcription factors are required for productive complex formation. The archaeal general TATA-element-binding protein (TBP), which mediates promoter recognition, factor B (TFB), recruitment RNAP, extensive to eukaryal TBP TFIIB. Crystallographic is becoming available fragments (e.g. TBP-TFB-DNA, TBP-TFIIB-DNA), but understanding molecular topography complete still biochemical biophysical characterization protein-protein protein-DNA interactions. In published work, systematic site-specific photocrosslinking has been used define positions bacterial complexes. we have an complex. Employing a set 41 derivatized fragments, each having phenyl azide photoactivable crosslinking agent incorporated single, defined site within -40 +1 gdh hyperthermophilic marine archaea, Pyrococcus furiosus (Pf), determined locations PfRNAP PfTBP PfTFB relative DNA. resulting topographical striking with permits one major new conclusion, that interacts not only TATA-element region also transcription-bubble region, near start site. Comparison crystallographic implicates N-terminal domain interaction region. results discussed relation known effects substitutions TFB TFIIB on start-site selection.