3no7

Crystal structure of the centromere-binding protein ParB from plasmid pCXC100

spinqualitylabelsall models 3no7, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3no7 is a 2 chain structure with sequence from Leifsonia xyli subsp. cynodontis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.4Å Ligands: SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q6EEF9_LEIXC Publication Abstract from PubMed Plasmid pCXC100 from the Gram-positive bacterium Leifsonia xyli subsp. cynodontis uses a type Ib partition system that includes a centromere region, a Walker-type ATPase ParA and a centromere-binding protein ParB for stable segregation. However, ParB shows no detectable sequence homology to any DNA-binding motif. Here, we study the ParB centromere interaction by structural and biochemical approaches. The crystal structure of the C-terminal DNA-binding domain of ParB at 1.4 A resolution reveals a dimeric ribbon-helix-helix (RHH) motif, supporting the prevalence of RHH motif in centromere binding. Using hydroxyl radical footprinting and quantitative binding assays, we show that the centromere core comprises nine uninterrupted 9-nt direct repeats that can be successively bound by ParB dimers in a cooperative manner. However, the interaction of ParB with a single subsite requires 18 base pairs covering one immediate repeat as well as two halves of flanking repeats. Through mutagenesis, sequence specificity was determined for each position of an 18-bp subsite. These data suggest an unique centromere recognition mechanism by which the repeat sequence is jointly specified by adjacent ParB dimers bound to an overlapped region. Crystal structure and centromere binding of the plasmid segregation protein ParB from pCXC100.,Huang L, Yin P, Zhu X, Zhang Y, Ye K Nucleic Acids Res. 2010 Dec 1. PMID:21123191 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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