9h45

Crystal Structure of Hfq V22A

spinqualitylabelsall models 9h45, resolution 2.08Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9h45 is a 7 chain structure with sequence from Escherichia coli K-12 and Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.08Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function 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. Seems to play a role in persister cell formation; upon overexpression decreases persister cell formation while deletion increases persister formation. 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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