4JRK

Crystal Structure of Escherichia coli Hfq Surface Mutant

Summary for 4JRK

• Entry DOI: 10.2210/pdb4jrk/pdb
• Related: 4JLI 4JRI
• Descriptor: Protein hfq (2 entities in total)
• Functional Keywords: riboregulator, post-transcriptional regulator, rna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 3
• Total formula weight: 23021.73

Authors

Robinson, K.E.,Orans, J. (deposition date: 2013-03-21, release date: 2013-12-11, Last modification date: 2024-02-28)

Primary citation

Robinson, K.E.,Orans, J.,Kovach, A.R.,Link, T.M.,Brennan, R.G.
Mapping Hfq-RNA interaction surfaces using tryptophan fluorescence quenching.
Nucleic Acids Res., 42:2736-2749, 2014

PubMed Abstract: 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.

PubMed: 24288369
DOI: 10.1093/nar/gkt1171

Experimental method

X-RAY DIFFRACTION (1.894 Å)