3qq6 | pdb_00003qq6

The N-terminal DNA binding domain of SinR from Bacillus subtilis

spinqualitylabelsall models 3qq6, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3qq6 is a 2 chain structure with sequence from Bacillus subtilis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1b0n Gene: BSU24610, flaD, sin, sinR (Bacillus subtilis) Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed sinR encodes a tetrameric repressor of genes required for biofilm formation in Bacillus subtilis. sinI, which is transcribed under Spo0A control, encodes a dimeric protein that binds to SinR to form a SinR-SinI heterodimer in which the DNA-binding functions of SinR are abrogated and repression of biofilm genes is relieved. The heterodimer-forming surface comprises residues conserved between SinR and SinI. Each forms a pair of alpha-helices that hook together to form an intermolecular four-helix bundle. Here, we are interested in the assembly of the SinR tetramer and its binding to DNA. Size-exclusion chromatography with multi-angle laser light scattering and crystallographic analysis reveal that a DNA-binding fragment of SinR (residues 1-69) is a monomer, while a SinI-binding fragment (residues 74-111) is a tetramer arranged as a dimer of dimers. The SinR(74-111) chain forms two alpha-helices with the organisation of the dimer similar to that observed in the SinR-SinI complex. The tetramer is formed through interactions of residues at the C-termini of the four chains. A model of the intact SinR tetramer in which the DNA binding domains surround the tetramerisation core was built. Fluorescence anisotropy and surface plasmon resonance experiments showed that SinR binds to an oligonucleotide duplex, 5'-TTTGTTCTCTAAAGAGAACTTA-3', containing a pair of SinR consensus sequences in inverted orientation with a K(d) of 300 nM. The implications of these data for promoter binding and the curious quaternary structural transitions of SinR upon binding to (i) SinI and (ii) the SinR-like protein SlrR, which "repurposes" SinR as a repressor of autolysin and motility genes, are discussed. Structure and Organisation of SinR, the Master Regulator of Biofilm Formation in Bacillus subtilis.,Colledge VL, Fogg MJ, Levdikov VM, Leech A, Dodson EJ, Wilkinson AJ J Mol Biol. 2011 Aug 19;411(3):597-613. Epub 2011 Jun 25. PMID:21708175 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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