View source for 6tps


==early intermediate RNA Polymerase I Pre-initiation complex - eiPIC==
<StructureSection load='6tps' size='340' side='right'caption='[[6tps]], [[Resolution|resolution]] 3.54&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6tps]] is a 22 chain structure with sequence from [http://en.wikipedia.org/wiki/ ] and [http://en.wikipedia.org/wiki/Saccharomyces_cerevisiae Saccharomyces cerevisiae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6TPS OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6TPS FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6tps FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6tps OCA], [http://pdbe.org/6tps PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6tps RCSB], [http://www.ebi.ac.uk/pdbsum/6tps PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6tps ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/RPAC2_YEAST RPAC2_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common core component of RNA polymerases I and III which synthesize ribosomal RNA precursors and small RNAs, such as 5S rRNA and tRNAs, respectively. [[http://www.uniprot.org/uniprot/RPA43_YEAST RPA43_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors. Through its association with RRN3 is involved in recruitment of Pol I to rDNA promoters. In vitro, the A13-A43 subcomplex binds single-stranded RNA.<ref>PMID:11032814</ref> <ref>PMID:12888498</ref>  [[http://www.uniprot.org/uniprot/RRN7_YEAST RRN7_YEAST]] Component of RNA polymerase I core factor complex (CF) that acts as a SUA7/TFIIB-like factor and plays a key role in multiple steps during transcription initiation such as pre-initiation complex (PIC) assembly and postpolymerase recruitment events in polymerase I (Pol I) transcription. Binds rDNA promoters and plays a role in Pol I recruitment. After binding of UAF (upstream activation factor) to an upstream element of the promoter, CF is recruited in a SPT15/TBP-dependent manner to form a pre-initiation complex.<ref>PMID:21921198</ref> <ref>PMID:21940764</ref> <ref>PMID:8887672</ref>  [[http://www.uniprot.org/uniprot/RPA2_YEAST RPA2_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Second largest core component of RNA polymerase I which synthesizes ribosomal RNA precursors. Proposed to contribute to the polymerase catalytic activity and forms the polymerase active center together with the largest subunit. Pol I is composed of mobile elements and RPA2 is part of the core element with the central large cleft and probably a clamp element that moves to open and close the cleft (By similarity). [[http://www.uniprot.org/uniprot/RPA1_YEAST RPA1_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Largest and catalytic core component of RNA polymerase I which synthesizes ribosomal RNA precursors. Forms the polymerase active center together with the second largest subunit. A single stranded DNA template strand of the promoter is positioned within the central active site cleft of Pol I. A bridging helix emanates from RPA1 and crosses the cleft near the catalytic site and is thought to promote translocation of Pol I by acting as a ratchet that moves the RNA-DNA hybrid through the active site by switching from straight to bent conformations at each step of nucleotide addition (By similarity). [[http://www.uniprot.org/uniprot/RRN11_YEAST RRN11_YEAST]] Acts as component of the core factor (CF) complex which is essential for the initiation of rDNA transcription by RNA polymerase I. After binding of UAF (upstream activation factor) to an upstream element of the promoter, CF is recruited in a SPT15/TBP-dependent manner to form a preinitiation complex.<ref>PMID:8887672</ref>  [[http://www.uniprot.org/uniprot/RRN6_YEAST RRN6_YEAST]] Acts as component of the core factor (CF) complex which is essential for the initiation of rDNA transcription by RNA polymerase I. After binding of UAF (upstream activation factor) to an upstream element of the promoter, CF is recruited in a SPT15/TBP-dependent manner to form a preinitiation complex.<ref>PMID:8887672</ref>  [[http://www.uniprot.org/uniprot/RPA49_YEAST RPA49_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors.  A49 is easily dissociated from the rest of pol A (pol I), producing the form A*, which shows impaired transcriptional activity and increased sensitivity to alpha-amanitin. The function of A49 might be linked to the RNase H activity that was found associated with this subunit. [[http://www.uniprot.org/uniprot/RPAB2_YEAST RPAB2_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and small RNAs, such as 5S rRNA and tRNAs, respectively. Pol II is the central component of the basal RNA polymerase II transcription machinery. Pols are composed of mobile elements that move relative to each other. In Pol II, RPB6 is part of the clamp element and togther with parts of RPB1 and RPB2 forms a pocket to which the RPB4-RPB7 subcomplex binds (By similarity). [[http://www.uniprot.org/uniprot/RPAC1_YEAST RPAC1_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I and III which synthesize ribosomal RNA precursors and small RNAs, such as 5S rRNA and tRNAs, respectively. RPAC1 is part of the Pol core element with the central large cleft and probably a clamp element that moves to open and close the cleft (By similarity). [[http://www.uniprot.org/uniprot/RPA12_YEAST RPA12_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors. Involved in transcriptional termination. Involved in recruitment of RPA49 to Pol I.<ref>PMID:15073335</ref>  [[http://www.uniprot.org/uniprot/RPAB4_YEAST RPAB4_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and a small RNAs, such as 5S rRNA and tRNAs, respectively. Pols are composed of mobile elements that move relative to each other. In Pol II, the core element with the central large cleft comprises RPB3, RBP10, RPB11, RPB12 and regions of RPB1 and RPB2 forming the active center. [[http://www.uniprot.org/uniprot/RPA34_YEAST RPA34_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors.<ref>PMID:9121426</ref>  [[http://www.uniprot.org/uniprot/RRN3_YEAST RRN3_YEAST]] Required for efficient transcription initiation by RNA polymerase I. Interacts with Pol I in the absence of template DNA and stimulates recruitment of Pol I, but does not remain as part of stable preinitiation complex. [[http://www.uniprot.org/uniprot/RPAB3_YEAST RPAB3_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and small RNAs, such as 5S rRNA and tRNAs, respectively. [[http://www.uniprot.org/uniprot/RPA14_YEAST RPA14_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase I which synthesizes ribosomal RNA precursors. A14 seems to play a role in the stability of subunits ABC23 and A43. In vitro, the A14-A43 subcomplex binds single-stranded RNA.<ref>PMID:12888498</ref>  [[http://www.uniprot.org/uniprot/RPAB5_YEAST RPAB5_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and a small RNAs, such as 5S rRNA and tRNAs, respectively. Pol II is the central component of the basal RNA polymerase II transcription machinery. Pols are composed of mobile elements that move relative to each other. In Pol II, RBP10 is part of the core element with the central large cleft. [[http://www.uniprot.org/uniprot/RPAB1_YEAST RPAB1_YEAST]] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and small RNAs, such as 5S rRNA and tRNAs, respectively. Pol II is the central component of the basal RNA polymerase II transcription machinery. Pols are composed of mobile elements that move relative to each other. In Pol II, RPB5 is part of the lower jaw surrounding the central large cleft and thought to grab the incoming DNA template. Seems to be the major component in this process (By similarity). 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Transcription of the ribosomal RNA precursor by RNA polymerase (Pol) I is a prerequisite for the biosynthesis of ribosomes in eukaryotes. Compared to Pols II and III, the mechanisms underlying promoter recognition, initiation complex formation and DNA melting by Pol I substantially diverge. Here, we report the high-resolution cryo-EM reconstruction of a Pol I early initiation intermediate assembled on a double-stranded promoter scaffold that prevents the establishment of downstream DNA contacts. Our analyses demonstrate how efficient promoter-backbone interaction is achieved by combined re-arrangements of flexible regions in the 'core factor' subunits Rrn7 and Rrn11. Furthermore, structure-function analysis illustrates how destabilization of the melted DNA region correlates with contraction of the polymerase cleft upon transcription activation, thereby combining promoter recruitment with DNA-melting. This suggests that molecular mechanisms and structural features of Pol I initiation have co-evolved to support the efficient melting, initial transcription and promoter clearance required for high-level rRNA synthesis.

Structural basis of RNA polymerase I pre-initiation complex formation and promoter melting.,Pilsl M, Engel C Nat Commun. 2020 Mar 5;11(1):1206. doi: 10.1038/s41467-020-15052-y. PMID:32139698<ref>PMID:32139698</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6tps" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: DNA-directed RNA polymerase]]
[[Category: Large Structures]]
[[Category: Saccharomyces cerevisiae]]
[[Category: Engel, C]]
[[Category: Pilsl, M]]
[[Category: Ribosome biosynthesis]]
[[Category: Rna polymerase i]]
[[Category: Transcription]]
[[Category: Transcription initiation]]