title: Crystallization of CcdB in complex with a GyrA fragment.
abstract: Plasmid addiction systems consist of a plasmid-encoded toxin-antidote pair that serves to stabilize low-copy-number plasmids in bacterial populations. CcdB, the toxin from the ccd system on the Escherichia coli F plasmid, acts as a gyrase poison. A 14 kDa fragment of gyrase, GyrA14, was found to bind to the toxin CcdB with an affinity of 1.75 x 10(-8) M. Crystals of the (GyrA14)(2) dimer in its free state belong to space group P4(3)2(1)2, with unit-cell parameters a = 86.4, c = 89.4 angstroms, and diffract to 2.4 angstroms. Crystals of the (GyrA14)(2)-(CcdB)(2) complex belong to space group P2(1)2(1)2(1), with a = 52.1, b = 83.3, c = 110.9 angstroms, and diffract to 2.8 angstroms resolution.
authors.affiliation: Laboratorium voor Ultrastructuur, Vlaams Instituut voor Biotechnologie, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium.
authors.forename: Minh Hoa
authors.initials: MH
authors.lastname: Dao-Thi
authors.forename: Laurence
authors.initials: L
authors.lastname: Van Melderen
authors.forename: Erwin
authors.initials: E
authors.lastname: De Genst
authors.forename: Lieven
authors.initials: L
authors.lastname: Buts
authors.forename: An
authors.initials: A
authors.lastname: Ranquin
authors.forename: Lode
authors.initials: L
authors.lastname: Wyns
authors.forename: Remy
authors.initials: R
authors.lastname: Loris
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D027081:DNA Gyrase / Q000737:chemistry*; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D005144:F Factor / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance; D014961:X-Ray Diffraction
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; C068356:CcdB protein, Plasmid F; D027081:DNA Gyrase