2v79

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==Overview==
==Overview==
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The DnaD protein is an essential component of the chromosome-replication machinery of the Gram-positive bacterium Bacillus subtilis and is part of the primosomal cascade that ultimately loads the replicative ring helicase DnaC onto DNA. Moreover, DnaD is a global regulator of DNA architecture, as it forms higher order nucleoprotein structures in order to open supercoiled DNA. Here, the crystallization and preliminary X-ray diffraction analysis of the two domains of DnaD from B. subtilis are reported. Crystals of the N-terminal domain are trigonal, with either P3(1)21 or P3(2)21 space-group symmetry, and diffracted X-rays to 2.0 A resolution; crystals of the C-terminal domain are hexagonal, with space group P6(1) or P6(5), and diffracted X-rays to 2.9 A resolution in-house. Determination of the structure of the DnaD domains will provide insight into how remodelling of the nucleoid is associated with priming of replication in the model Gram-positive organism B. subtilis.
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DnaD is a primosomal protein that remodels supercoiled plasmids. It binds to supercoiled forms and converts them to open forms without nicking. During this remodeling process, all the writhe is converted to twist and the plasmids are held around the periphery of large scaffolds made up of DnaD molecules. This DNA-remodeling function is the sum of a scaffold-forming activity on the N-terminal domain and a DNA-dependent oligomerization activity on the C-terminal domain. We have determined the crystal structure of the scaffold-forming N-terminal domain, which reveals a winged-helix architecture, with additional structural elements extending from both N- and C-termini. Four monomers form dimers that join into a tetramer. The N-terminal extension mediates dimerization and tetramerization, with extensive interactions and distinct interfaces. The wings and helices of the winged-helix domains remain exposed on the surface of the tetramer. Structure-guided mutagenesis and atomic force microscopy imaging indicate that these elements, together with the C-terminal extension, are involved in scaffold formation. Based upon our data, we propose a model for the DnaD-mediated scaffold formation.
==About this Structure==
==About this Structure==
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==Reference==
==Reference==
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Crystallization and X-ray diffraction analysis of the DNA-remodelling protein DnaD from Bacillus subtilis., Schneider S, Carneiro MJ, Ioannou C, Soultanas P, Paoli M, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2007 Feb 1;63(Pt, 2):110-3. Epub 2007 Jan 17. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17277452 17277452]
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Structure of the N-terminal oligomerization domain of DnaD reveals a unique tetramerization motif and provides insights into scaffold formation., Schneider S, Zhang W, Soultanas P, Paoli M, J Mol Biol. 2008 Mar 7;376(5):1237-50. Epub 2007 Dec 28. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18206906 18206906]
[[Category: Bacillus subtilis]]
[[Category: Bacillus subtilis]]
[[Category: Single protein]]
[[Category: Single protein]]
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[[Category: primosome]]
[[Category: primosome]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:53:39 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Feb 27 07:48:15 2008''

Revision as of 05:48, 27 February 2008


2v79, resolution 2.00Å

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CRYSTAL STRUCTURE OF THE N-TERMINAL DOMAIN OF DNAD FROM BACILLUS SUBTILIS

Overview

DnaD is a primosomal protein that remodels supercoiled plasmids. It binds to supercoiled forms and converts them to open forms without nicking. During this remodeling process, all the writhe is converted to twist and the plasmids are held around the periphery of large scaffolds made up of DnaD molecules. This DNA-remodeling function is the sum of a scaffold-forming activity on the N-terminal domain and a DNA-dependent oligomerization activity on the C-terminal domain. We have determined the crystal structure of the scaffold-forming N-terminal domain, which reveals a winged-helix architecture, with additional structural elements extending from both N- and C-termini. Four monomers form dimers that join into a tetramer. The N-terminal extension mediates dimerization and tetramerization, with extensive interactions and distinct interfaces. The wings and helices of the winged-helix domains remain exposed on the surface of the tetramer. Structure-guided mutagenesis and atomic force microscopy imaging indicate that these elements, together with the C-terminal extension, are involved in scaffold formation. Based upon our data, we propose a model for the DnaD-mediated scaffold formation.

About this Structure

2V79 is a Single protein structure of sequence from Bacillus subtilis with and as ligands. Known structural/functional Sites: , , , , , , , , , , , , and . Full crystallographic information is available from OCA.

Reference

Structure of the N-terminal oligomerization domain of DnaD reveals a unique tetramerization motif and provides insights into scaffold formation., Schneider S, Zhang W, Soultanas P, Paoli M, J Mol Biol. 2008 Mar 7;376(5):1237-50. Epub 2007 Dec 28. PMID:18206906

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