5iyd
From Proteopedia
Human core-PIC in the initial transcribing state (no IIS)
Structural highlights
FunctionRPB4_HUMAN DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase II which synthesizes mRNA precursors and many functional non-coding RNAs. Pol II is the central component of the basal RNA polymerase II transcription machinery. It is composed of mobile elements that move relative to each other. RPB4 is part of a subcomplex with RPB7 that binds to a pocket formed by RPB1, RPB2 and RPB6 at the base of the clamp element. The RBP4-RPB7 subcomplex seems to lock the clamp via RPB7 in the closed conformation thus preventing double-stranded DNA to enter the active site cleft. The RPB4-RPB7 subcomplex binds single-stranded DNA and RNA (By similarity).[1] Publication Abstract from PubMedIn 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. Near-atomic resolution visualization of human transcription promoter opening.,He Y, Yan C, Fang J, Inouye C, Tjian R, Ivanov I, Nogales E Nature. 2016 May 11;533(7603):359-65. doi: 10.1038/nature17970. PMID:27193682[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also
References
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Categories: Homo sapiens | Large Structures | Fang J | He Y | Inouye C | Ivanov I | Nogales E | Tjian R | Yan C
