3qsu | pdb_00003qsu

Structure of Staphylococcus aureus Hfq in complex with A7 RNA

spinqualitylabelsall models 3qsu, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3qsu is a 16 chain structure with sequence from Staag. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ZN Related: 3gib, 1kq1, 1kq2, 3hsb Gene: ECTR2_1161, hfq (STAAG) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [E5RBT2_STAAG] 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. Also binds with high specificity to tRNAs (By similarity).[SAAS:SAAS001163_004_036087] Publication Abstract from PubMed Hfq is a post-transcriptional regulator that plays a key role in bacterial gene expression by binding AU-rich sequences and A-tracts to facilitate the annealing of sRNAs to target mRNAs and to affect RNA stability. To understand how Hfq from the Gram-positive bacterium Staphylococcus aureus (Sa) binds A-tract RNA, we determined the crystal structure of an Sa Hfq-adenine oligoribonucleotide complex. The structure reveals a bipartite RNA-binding motif on the distal face that is composed of a purine nucleotide-specificity site (R-site) and a non-discriminating linker site (L-site). The (R-L)-binding motif, which is also utilized by Bacillus subtilis Hfq to bind (AG)(3)A, differs from the (A-R-N) tripartite poly(A) RNA-binding motif of Escherichia coli Hfq whereby the Sa Hfq R-site strongly prefers adenosine, is more aromatic and permits deeper insertion of the adenine ring. R-site adenine-stacking residue Phe30, which is conserved among Gram-positive bacterial Hfqs, and an altered conformation about beta3 and beta4 eliminate the adenosine-specificity site (A-site) and create the L-site. Binding studies show that Sa Hfq binds (AU)(3)A approximately (AG)(3)A >/= (AC)(3)A > (AA)(3)A and L-site residue Lys33 plays a significant role. The (R-L) motif is likely utilized by Hfqs from most Gram-positive bacteria to bind alternating (A-N)(n) RNA. Structural mechanism of Staphylococcus aureus Hfq binding to an RNA A-tract.,Horstmann N, Orans J, Valentin-Hansen P, Shelburne SA 3rd, Brennan RG Nucleic Acids Res. 2012 Sep 10. PMID:22965117 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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