We apologize for Proteopedia being slow to respond. For the past two years, a new implementation of Proteopedia has been being built. Soon, it will replace this 18-year old system. All existing content will be moved to the new system at a date that will be announced here.

4a3l

From Proteopedia

Jump to: navigation, search

RNA Polymerase II initial transcribing complex with a 7nt DNA-RNA hybrid and soaked with AMPCPP

Structural highlights

4a3l is a 10 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3.5Å
Ligands:	, , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RPB9_YEAST 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. RPB9 is part of the upper jaw surrounding the central large cleft and thought to grab the incoming DNA template. Involved in the regulation of transcription elongation. Involved in DNA repair of damage in the transcribed strand. Mediates a transcription-coupled repair (TCR) subpathway of nucleotide excision repair (NER).^[1]

Publication Abstract from PubMed

During transcription initiation by RNA polymerase (Pol) II, a transient open promoter complex (OC) is converted to an initially transcribing complex (ITC) containing short RNAs, and to a stable elongation complex (EC). We report structures of a Pol II-DNA complex mimicking part of the OC, and of complexes representing minimal ITCs with 2, 4, 5, 6, and 7 nucleotide (nt) RNAs, with and without a non-hydrolyzable nucleoside triphosphate (NTP) in the insertion site +1. The partial OC structure reveals that Pol II positions the melted template strand opposite the active site. The ITC-mimicking structures show that two invariant lysine residues anchor the 3'-proximal phosphate of short RNAs. Short DNA-RNA hybrids adopt a tilted conformation that excludes the +1 template nt from the active site. NTP binding induces complete DNA translocation and the standard hybrid conformation. Conserved NTP contacts indicate a universal mechanism of NTP selection. The essential residue Q1078 in the closed trigger loop binds the NTP 2'-OH group, explaining how the trigger loop couples catalysis to NTP selection, suppressing dNTP binding and DNA synthesis.

Structural basis of initial RNA polymerase II transcription.,Cheung AC, Sainsbury S, Cramer P EMBO J. 2011 Nov 4. doi: 10.1038/emboj.2011.396. PMID:22056778^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Li S, Smerdon MJ. Rpb4 and Rpb9 mediate subpathways of transcription-coupled DNA repair in Saccharomyces cerevisiae. EMBO J. 2002 Nov 1;21(21):5921-9. PMID:12411509
↑ Cheung AC, Sainsbury S, Cramer P. Structural basis of initial RNA polymerase II transcription. EMBO J. 2011 Nov 4. doi: 10.1038/emboj.2011.396. PMID:22056778 doi:10.1038/emboj.2011.396