5fmf
the P-lobe of RNA polymerase II pre-initiation complex
Structural highlights
FunctionRAD25_YEAST Probably an ATP-dependent DNA helicase, which may have a DNA unwinding function. Has an essential function in translation initiation. 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 PubMedThe structure of a 33-protein, 1.5-MDa RNA polymerase II preinitiation complex (PIC) was determined by cryo-EM and image processing at a resolution of 6-11 A. Atomic structures of over 50% of the mass were fitted into the electron density map in a manner consistent with protein-protein cross-links previously identified by mass spectrometry. The resulting model of the PIC confirmed the main conclusions from previous cryo-EM at lower resolution, including the association of promoter DNA only with general transcription factors and not with the polymerase. Electron density due to DNA was identifiable by the grooves of the double helix and exhibited sharp bends at points downstream of the TATA box, with an important consequence: The DNA at the downstream end coincides with the DNA in a transcribing polymerase. The structure of the PIC is therefore conducive to promoter melting, start-site scanning, and the initiation of transcription. Structure of an RNA polymerase II preinitiation complex.,Murakami K, Tsai KL, Kalisman N, Bushnell DA, Asturias FJ, Kornberg RD Proc Natl Acad Sci U S A. 2015 Nov 3;112(44):13543-8. doi:, 10.1073/pnas.1518255112. Epub 2015 Oct 19. PMID:26483468[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
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