| Structural highlights
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.[1] [2] [3] [4] [5] Seems to play a role in persister cell formation; upon overexpression decreases persister cell formation while deletion increases persister formation.[6] [7] [8] [9] [10]
Publication Abstract from PubMed
Hfq is a posttranscriptional riboregulator and RNA chaperone that binds small RNAs and target mRNAs to effect their annealing and message-specific regulation in response to environmental stressors. Structures of Hfq-RNA complexes indicate that U-rich sequences prefer the proximal face and A-rich sequences the distal face; however, the Hfq-binding sites of most RNAs are unknown. Here, we present an Hfq-RNA mapping approach that uses single tryptophan-substituted Hfq proteins, all of which retain the wild-type Hfq structure, and tryptophan fluorescence quenching (TFQ) by proximal RNA binding. TFQ properly identified the respective distal and proximal binding of A15 and U6 RNA to Gram-negative Escherichia coli (Ec) Hfq and the distal face binding of (AA)3A, (AU)3A and (AC)3A to Gram-positive Staphylococcus aureus (Sa) Hfq. The inability of (GU)3G to bind the distal face of Sa Hfq reveals the (R-L)n binding motif is a more restrictive (A-L)n binding motif. Remarkably Hfq from Gram-positive Listeria monocytogenes (Lm) binds (GU)3G on its proximal face. TFQ experiments also revealed the Ec Hfq (A-R-N)n distal face-binding motif should be redefined as an (A-A-N)n binding motif. TFQ data also demonstrated that the 5'-untranslated region of hfq mRNA binds both the proximal and distal faces of Ec Hfq and the unstructured C-terminus.
Mapping Hfq-RNA interaction surfaces using tryptophan fluorescence quenching.,Robinson KE, Orans J, Kovach AR, Link TM, Brennan RG Nucleic Acids Res. 2013 Nov 27. PMID:24288369[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Carmichael GG, Weber K, Niveleau A, Wahba AJ. The host factor required for RNA phage Qbeta RNA replication in vitro. Intracellular location, quantitation, and purification by polyadenylate-cellulose chromatography. J Biol Chem. 1975 May 25;250(10):3607-612. PMID:805130
- ↑ Hajnsdorf E, Regnier P. Host factor Hfq of Escherichia coli stimulates elongation of poly(A) tails by poly(A) polymerase I. Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1501-5. PMID:10677490 doi:10.1073/pnas.040549897
- ↑ Sledjeski DD, Whitman C, Zhang A. Hfq is necessary for regulation by the untranslated RNA DsrA. J Bacteriol. 2001 Mar;183(6):1997-2005. PMID:11222598 doi:10.1128/JB.183.6.1997-2005.2001
- ↑ Guisbert E, Rhodius VA, Ahuja N, Witkin E, Gross CA. Hfq modulates the sigmaE-mediated envelope stress response and the sigma32-mediated cytoplasmic stress response in Escherichia coli. J Bacteriol. 2007 Mar;189(5):1963-73. Epub 2006 Dec 8. PMID:17158661 doi:10.1128/JB.01243-06
- ↑ Kim Y, Wood TK. Toxins Hha and CspD and small RNA regulator Hfq are involved in persister cell formation through MqsR in Escherichia coli. Biochem Biophys Res Commun. 2010 Jan 1;391(1):209-13. doi:, 10.1016/j.bbrc.2009.11.033. Epub 2009 Nov 10. PMID:19909729 doi:10.1016/j.bbrc.2009.11.033
- ↑ Carmichael GG, Weber K, Niveleau A, Wahba AJ. The host factor required for RNA phage Qbeta RNA replication in vitro. Intracellular location, quantitation, and purification by polyadenylate-cellulose chromatography. J Biol Chem. 1975 May 25;250(10):3607-612. PMID:805130
- ↑ Hajnsdorf E, Regnier P. Host factor Hfq of Escherichia coli stimulates elongation of poly(A) tails by poly(A) polymerase I. Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1501-5. PMID:10677490 doi:10.1073/pnas.040549897
- ↑ Sledjeski DD, Whitman C, Zhang A. Hfq is necessary for regulation by the untranslated RNA DsrA. J Bacteriol. 2001 Mar;183(6):1997-2005. PMID:11222598 doi:10.1128/JB.183.6.1997-2005.2001
- ↑ Guisbert E, Rhodius VA, Ahuja N, Witkin E, Gross CA. Hfq modulates the sigmaE-mediated envelope stress response and the sigma32-mediated cytoplasmic stress response in Escherichia coli. J Bacteriol. 2007 Mar;189(5):1963-73. Epub 2006 Dec 8. PMID:17158661 doi:10.1128/JB.01243-06
- ↑ Kim Y, Wood TK. Toxins Hha and CspD and small RNA regulator Hfq are involved in persister cell formation through MqsR in Escherichia coli. Biochem Biophys Res Commun. 2010 Jan 1;391(1):209-13. doi:, 10.1016/j.bbrc.2009.11.033. Epub 2009 Nov 10. PMID:19909729 doi:10.1016/j.bbrc.2009.11.033
- ↑ Robinson KE, Orans J, Kovach AR, Link TM, Brennan RG. Mapping Hfq-RNA interaction surfaces using tryptophan fluorescence quenching. Nucleic Acids Res. 2013 Nov 27. PMID:24288369 doi:http://dx.doi.org/10.1093/nar/gkt1171
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