View source for 6byu


==X-ray crystal structure of Escherichia coli RNA polymerase (RpoB-H526Y) and ppApp complex==
<StructureSection load='6byu' size='340' side='right'caption='[[6byu]], [[Resolution|resolution]] 3.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6byu]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6BYU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6BYU 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]] 3.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ECJ:[(5~{R})-5-(6-aminopurin-9-yl)-4-oxidanylidene-3-[oxidanyl(phosphonooxy)phosphoryl]oxy-furan-2-yl]methyl+phosphono+hydrogen+phosphate'>ECJ</scene>, <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=6byu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6byu OCA], [https://pdbe.org/6byu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6byu RCSB], [https://www.ebi.ac.uk/pdbsum/6byu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6byu ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RPOA_ECOLI RPOA_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit plays an important role in subunit assembly since its dimerization is the first step in the sequential assembly of subunits to form the holoenzyme.[HAMAP-Rule:MF_00059]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Precise regulation of gene expression is crucial for bacteria to respond to changing environmental conditions. In addition to protein factors affecting RNA polymerase (RNAP) activity, second messengers play an important role in transcription regulation, such as well-known effectors of the stringent response: guanosine 5'triphosphate-3'diphosphate and guanosine 3', 5'-bis(diphosphate) [(p)ppGpp]. Although much is known about importance of the 5' and 3' moieties of (p)ppGpp, the role of the guanine base remains somewhat cryptic. Here, we use (p)ppGpp's adenine analogs [(p)ppApp] to investigate how the nucleobase contributes to determine its binding site and transcriptional regulation. We determined X-ray crystal structure of Escherichia coli RNAP-(p)ppApp complex, which shows the analogs bind near the active site and switch regions of RNAP. We have also explored the regulatory effects of (p)ppApp on transcription initiating from the well-studied E. coli rrnB P1 promoter to assess and compare properties of (p)ppApp with (p)ppGpp. We demonstrate that contrary to (p)ppGpp, (p)ppApp activates transcription at this promoter and DksA hinders this effect. Moreover, pppApp exerts a stronger effect than ppApp. We also show that when ppGpp and pppApp are present together, the outcome depends on which one of them was pre-incubated with RNAP first. This behavior suggests a surprising Yin-Yang like reciprocal plasticity of RNAP responses at a single promoter, occasioned simply by pre-exposure to one or the other nucleotide. Our observations underscore the importance of the (p)ppNpp's purine nucleobase for interactions with RNAP, which may lead to a better fundamental understanding of (p)ppGpp regulation of RNAP activity.

Structure-function comparisons of (p)ppApp vs (p)ppGpp for Escherichia coli RNA polymerase binding sites and for rrnB P1 promoter regulatory responses in vitro.,Bruhn-Olszewska B, Molodtsov V, Sobala M, Dylewski M, Murakami KS, Cashel M, Potrykus K Biochim Biophys Acta. 2018 Aug;1861(8):731-742. doi:, 10.1016/j.bbagrm.2018.07.005. Epub 2018 Jul 18. PMID:30012465<ref>PMID:30012465</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6byu" 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: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Molodtsov V]]
[[Category: Murakami KS]]