View source for 4xlr


==Crystal structure of T.aquaticus transcription initiation complex with CarD containing bubble promoter and RNA==
<StructureSection load='4xlr' size='340' side='right'caption='[[4xlr]], [[Resolution|resolution]] 4.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4xlr]] is a 20 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus], [https://en.wikipedia.org/wiki/Thermus_thermophilus_JL-18 Thermus thermophilus JL-18] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4XLR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4XLR FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 4.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4xlr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4xlr OCA], [https://pdbe.org/4xlr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4xlr RCSB], [https://www.ebi.ac.uk/pdbsum/4xlr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4xlr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RPOA_THEAQ RPOA_THEAQ] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
A key point to regulate gene expression is at transcription initiation, and activators play a major role. CarD, an essential activator in Mycobacterium tuberculosis, is found in many bacteria, including Thermus species, but absent in Escherichia coli. To delineate the molecular mechanism of CarD, we determined crystal structures of Thermus transcription initiation complexes containing CarD. The structures show CarD interacts with the unique DNA topology presented by the upstream double-stranded/single-stranded DNA junction of the transcription bubble. We confirm that our structures correspond to functional activation complexes, and extend our understanding of the role of a conserved CarD Trp residue that serves as a minor groove wedge, preventing collapse of the transcription bubble to stabilize the transcription initiation complex. Unlike E. coli RNAP, many bacterial RNAPs form unstable promoter complexes, explaining the need for CarD.

CarD uses a minor groove wedge mechanism to stabilize the RNA polymerase open promoter complex.,Bae B, Chen J, Davis E, Leon K, Darst SA, Campbell EA Elife. 2015 Sep 8;4. doi: 10.7554/eLife.08505. PMID:26349034<ref>PMID:26349034</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4xlr" style="background-color:#fffaf0;"></div>

==See Also==
*[[RNA polymerase 3D structures|RNA polymerase 3D structures]]
*[[Sigma factor 3D structures|Sigma factor 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Thermus aquaticus]]
[[Category: Thermus thermophilus JL-18]]
[[Category: Bae B]]
[[Category: Darst SA]]