Crystallization of ccdB.
CcdB is a small dimeric protein that poisons DNA-topoisomerase II complexes. Its crystallization properties in terms of precipitant type, precipitant concentration, pH and protein concentration have been investigated leading to a novel crystal form which, in contrast to previously reported crystals, is suitable for structure determination using the multiple isomorphous replacement (MIR) method. The space group of this new form is C2, with unit-cell parameters a = 74.94, b = 36.24, c = 35.77 A, beta = 115.27 degrees. The asymmetric unit contains a single monomer. Flash-frozen crystals diffract to at least 1.5 A resolution, while room-temperature diffraction can be observed up to 1.6 A. The double mutant S74C/G77Q, which acts as a super-killer, crystallizes in space group I222 (or I212121) with unit-cell dimensions a = 105.58, b = 105.80, c = 91.90 A. These crystals diffract to 2.5 A resolution.
Laboratorium voor Ultrastructuur, Vlaams Interuniversitair Instituut Biotechnologie, Vrije Universiteit Brussel, Paardenstraat 65, B-1640 Sint-Genesius-Rode, Belgium.
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Dao-Thi
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Wyns
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Poortmans
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Bahassi
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Couturier
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Loris
D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D003460:Crystallization; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000302:isolation & purification; D004926:Escherichia coli; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000302:isolation & purification*; D059005:Topoisomerase II Inhibitors
D001426:Bacterial Proteins; D001427:Bacterial Toxins; C068356:CcdB protein, Plasmid F; D004791:Enzyme Inhibitors; D011993:Recombinant Fusion Proteins; D059005:Topoisomerase II Inhibitors