View source for 9gu5


==Crystal Structure of Hfq V22A==
<StructureSection load='9gu5' size='340' side='right'caption='[[9gu5]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9gu5]] is a 13 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12] and [https://en.wikipedia.org/wiki/RNA_interference_vector_pBSK-Gus RNA interference vector pBSK-Gus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9GU5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9GU5 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]] 2.9&#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></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=9gu5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9gu5 OCA], [https://pdbe.org/9gu5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9gu5 RCSB], [https://www.ebi.ac.uk/pdbsum/9gu5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9gu5 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 ==
The RNA chaperone Hfq plays crucial roles in bacterial gene expression and is a major facilitator of small regulatory RNA (sRNA) action. The toroidal architecture of the Hfq hexamer presents three well-characterized surfaces that allow it to bind sRNAs to stabilize them and engage target transcripts. Hfq-interacting sRNAs are categorized into two classes based on the surfaces they use to bind Hfq. By characterizing a systematic alanine mutant library of Hfq to identify amino acid residues that impact survival of Escherichia coli experiencing nitrogen (N) starvation, we corroborated the important role of the three RNA-binding surfaces for Hfq function. We uncovered two, previously uncharacterized, conserved residues, V22 and G34, in the hydrophobic core of Hfq, to have a profound impact on Hfq's RNA-binding activity in vivo. Transcriptome-scale analysis revealed that V22A and G34A Hfq mutants cause widespread destabilization of both sRNA classes, to the same extent as seen in bacteria devoid of Hfq. However, the alanine substitutions at these residues resulted in only modest alteration in stability and structure of Hfq. We propose that V22 and G34 have impact on Hfq function, especially critical under cellular conditions when there is an increased demand for Hfq, such as N starvation.

Transcriptome-scale analysis uncovers conserved residues in the hydrophobic core of the bacterial RNA chaperone Hfq required for small regulatory RNA stability.,McQuail J, Krepl M, Katsuya-Gaviria K, Tabib-Salazar A, Burchell L, Bischler T, Grafenhan T, Brear P, Sponer J, Luisi BF, Wigneshweraraj S Nucleic Acids Res. 2025 Jan 24;53(3):gkaf019. doi: 10.1093/nar/gkaf019. PMID:39868539<ref>PMID:39868539</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9gu5" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: RNA interference vector pBSK-Gus]]
[[Category: Bischler T]]
[[Category: Brear P]]
[[Category: Burchell L]]
[[Category: Grafenhan T]]
[[Category: Katsuya-Gaviria K]]
[[Category: Krepl M]]
[[Category: Luisi B]]
[[Category: McQuail J]]
[[Category: Tabib-Salazar A]]