7o4l
From Proteopedia
Yeast TFIIH in the expanded state within the pre-initiation complex
Structural highlights
FunctionRAD3_YEAST ATP-dependent DNA helicase involved in excision repair of DNA damaged with UV light, bulky adducts, or cross-linking agents. Necessary for excision of pyrimidine dimers. Also unwinds DNA/RNA duplexes. Plays an essential role in the cell viability. Involved in the maintenance of the fidelity of DNA replication. Acts as component of the general transcription and DNA repair factor IIH (TFIIH) core, which is essential for both basal and activated transcription, and is involved in nucleotide excision repair (NER) of damaged DNA. TFIIH has CTD kinase and DNA-dependent ATPase activity, and is essential for polymerase II transcription in vitro.[1] [2] Publication Abstract from PubMedTranscription initiation requires assembly of the RNA polymerase II (Pol II) pre-initiation complex (PIC) and opening of promoter DNA. Here, we present the long-sought high-resolution structure of the yeast PIC and define the mechanism of initial DNA opening. We trap the PIC in an intermediate state that contains half a turn of open DNA located 30-35 base pairs downstream of the TATA box. The initially opened DNA region is flanked and stabilized by the polymerase "clamp head loop" and the TFIIF "charged region" that both contribute to promoter-initiated transcription. TFIIE facilitates initiation by buttressing the clamp head loop and by regulating the TFIIH translocase. The initial DNA bubble is then extended in the upstream direction, leading to the open promoter complex and enabling start-site scanning and RNA synthesis. This unique mechanism of DNA opening may permit more intricate regulation than in the Pol I and Pol III systems. Structure of RNA polymerase II pre-initiation complex at 2.9 A defines initial DNA opening.,Schilbach S, Aibara S, Dienemann C, Grabbe F, Cramer P Cell. 2021 Jul 22;184(15):4064-4072.e28. doi: 10.1016/j.cell.2021.05.012. Epub , 2021 Jun 15. PMID:34133942[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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