2q2k: Difference between revisions
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Revision as of 09:14, 13 February 2008
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Structure of nucleic-acid binding protein
OverviewOverview
The stable inheritance of genetic material depends on accurate DNA, partition. Plasmids serve as tractable model systems to study DNA, segregation because they require only a DNA centromere, a, centromere-binding protein and a force-generating ATPase. The centromeres, of partition (par) systems typically consist of a tandem arrangement of, direct repeats. The best-characterized par system contains a, centromere-binding protein called ParR and an ATPase called ParM. In the, first step of segregation, multiple ParR proteins interact with the, centromere repeats to form a large nucleoprotein complex of unknown, structure called the segrosome, which binds ParM filaments. pSK41 ParR, binds a centromere consisting of multiple 20-base-pair (bp) tandem repeats, to mediate both transcription autoregulation and segregation. Here we, report the structure of the pSK41 segrosome revealed in the crystal, structure of a ParR-DNA complex. In the crystals, the 20-mer tandem, repeats stack pseudo-continuously to generate the full-length centromere, with the ribbon-helix-helix (RHH) fold of ParR binding successive DNA, repeats as dimer-of-dimers. Remarkably, the dimer-of-dimers assemble in a, continuous protein super-helical array, wrapping the DNA about its, positive convex surface to form a large segrosome with an open, solenoid-shaped structure, suggesting a mechanism for ParM capture and, subsequent plasmid segregation.
About this StructureAbout this Structure
2Q2K is a Single protein structure of sequence from Staphylococcus aureus with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Segrosome structure revealed by a complex of ParR with centromere DNA., Schumacher MA, Glover TC, Brzoska AJ, Jensen SO, Dunham TD, Skurray RA, Firth N, Nature. 2007 Dec 20;450(7173):1268-71. PMID:18097417
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