View source for 3qo3


==Crystal structure of Escherichia coli Hfq, in complex with ATP==
<StructureSection load='3qo3' size='340' side='right'caption='[[3qo3]], [[Resolution|resolution]] 2.15&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3qo3]] is a 6 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=3QO3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3QO3 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]] 2.15&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</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=3qo3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qo3 OCA], [https://pdbe.org/3qo3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3qo3 RCSB], [https://www.ebi.ac.uk/pdbsum/3qo3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3qo3 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HFQ_ECOLI HFQ_ECOLI] RNA chaperone that binds small regulatory RNA (sRNAs) and mRNAs to facilitate mRNA translational regulation in response to envelope stress, environmental stress and changes in metabolite concentrations. Involved in the regulation of stress responses mediated by the sigma factors RpoS, sigma-E and sigma-32. Binds with high specificity to tRNAs. In vitro, stimulates synthesis of long tails by poly(A) polymerase I. Required for RNA phage Qbeta replication.<ref>PMID:805130</ref> <ref>PMID:10677490</ref> <ref>PMID:11222598</ref> <ref>PMID:17158661</ref> <ref>PMID:19909729</ref>   Seems to play a role in persister cell formation; upon overexpression decreases persister cell formation while deletion increases persister formation.<ref>PMID:805130</ref> <ref>PMID:10677490</ref> <ref>PMID:11222598</ref> <ref>PMID:17158661</ref> <ref>PMID:19909729</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In Escherichia coli the RNA chaperone Hfq is involved in riboregulation by assisting base-pairing between small regulatory RNAs (sRNAs) and mRNA targets. Several structural and biochemical studies revealed RNA binding sites on either surface of the donut shaped Hfq-hexamer. Whereas sRNAs are believed to contact preferentially the YKH motifs present on the proximal site, poly(A)(15) and ADP were shown to bind to tripartite binding motifs (ARE) circularly positioned on the distal site. Hfq has been reported to bind and to hydrolyze ATP. Here, we present the crystal structure of a C-terminally truncated variant of E. coli Hfq (Hfq(65)) in complex with ATP, showing that it binds to the distal R-sites. In addition, we revisited the reported ATPase activity of full length Hfq purified to homogeneity. At variance with previous reports, no ATPase activity was observed for Hfq. In addition, FRET assays neither indicated an impact of ATP on annealing of two model oligoribonucleotides nor did the presence of ATP induce strand displacement. Moreover, ATP did not lead to destabilization of binary and ternary Hfq-RNA complexes, unless a vast stoichiometric excess of ATP was used. Taken together, these studies strongly suggest that ATP is dispensable for and does not interfere with Hfq-mediated RNA transactions.

Structural and biochemical studies on ATP binding and hydrolysis by the Escherichia coli RNA chaperone Hfq.,Hammerle H, Beich-Frandsen M, Vecerek B, Rajkowitsch L, Carugo O, Djinovic-Carugo K, Blasi U PLoS One. 2012;7(11):e50892. doi: 10.1371/journal.pone.0050892. Epub 2012 Nov 30. PMID:23226421<ref>PMID:23226421</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3qo3" style="background-color:#fffaf0;"></div>

==See Also==
*[[Protein Hfq 3D structures|Protein Hfq 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Beich-Frandsen M]]
[[Category: Blasi U]]
[[Category: Djinovic-Carugo K]]
[[Category: Hammele H]]
[[Category: Kloiber K]]
[[Category: Sjoeblom B]]
[[Category: Vecerek B]]