5IY9 : Human holo-PIC in the initial transcribing state (no IIS)

  • Yuan He (Contributor)
  • Chunli Yan (Contributor)
  • Jie Fang (Contributor)
  • Carla Inouye (Contributor)
  • Robert Tjian (Contributor)
  • Ivaylo Ivanov (Contributor)
  • Eva Nogales (Contributor)



Experimental Technique/Method:ELECTRON MICROSCOPY
Release Date:2016-05-18
Deposition Date:2016-03-24
Revision Date:2016-05-25#2016-06-22#2017-09-13
Molecular Weight:1182769.75
Macromolecule Type:Protein#DNA#RNA
Residue Count:10173
Atom Site Count:61725

In eukaryotic transcription initiation, a large multi-subunit pre-initiation complex (PIC) that assembles at the core promoter is required for the opening of the duplex DNA and identification of the start site for transcription by RNA polymerase II. Here we use cryo-electron microscropy (cryo-EM) to determine near-atomic resolution structures of the human PIC in a closed state (engaged with duplex DNA), an open state (engaged with a transcription bubble), and an initially transcribing complex (containing six base pairs of DNA-RNA hybrid). Our studies provide structures for previously uncharacterized components of the PIC, such as TFIIE and TFIIH, and segments of TFIIA, TFIIB and TFIIF. Comparison of the different structures reveals the sequential conformational changes that accompany the transition from each state to the next throughout the transcription initiation process. This analysis illustrates the key role of TFIIB in transcription bubble stabilization and provides strong structural support for a translocase activity of XPB.
Date made available2016

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