title: Crystallization and preliminary X-ray crystallographic studies on the parD-encoded protein Kid from Escherichia coli plasmid R1.
abstract: DNA replication in Escherichia coli and therefore bacterial proliferation relies upon the efficient functioning of the DnaB helicase. The toxin protein Kid from the plasmid-stability system parD encoded on plasmid R1 of E. coli is thought to target and block DnaB-dependent DNA replication. The toxicity of Kid is antagonized through interaction with the Kis antidote protein and the resultant complex can then act as a transcriptional regulator for the parD system. Crystals of selenomethionine-incorporated Kid have been obtained by the hanging-drop vapour-diffusion method using potassium phosphate as the precipitant. The crystals belong to the monoclinic system, space group P2(1), have unit-cell parameters a = 32.9, b = 45.0, c = 64.4 A, beta = 96.2 degrees and diffract to a d(min) of better than 1.8 A on a synchrotron-radiation source. The determination of the structure of Kid will permit a better understanding of its interactions with DnaB and Kis and allow the evolutionary relationships of Kid to other toxins of plasmid and chromosomal origin to be explored.
authors.affiliation: Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield S10 2TN, England.
authors.forename: David
authors.initials: D
authors.lastname: Hargreaves
authors.forename: Rafael
authors.initials: R
authors.lastname: Giraldo
authors.forename: Sandra
authors.initials: S
authors.lastname: Santos-Sierra
authors.forename: Rolf
authors.initials: R
authors.lastname: Boelens
authors.forename: David W
authors.initials: DW
authors.lastname: Rice
authors.forename: Ramón
authors.initials: R
authors.lastname: Díaz Orejas
authors.forename: John B
authors.initials: JB
authors.lastname: Rafferty
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D010957:Plasmids / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D012645:Selenomethionine / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C489746:ParD protein, E coli; C489749:ParD protein, Plasmid R1; C078613:parD protein, Bacteria; D012645:Selenomethionine