title: Crystallization and preliminary X-ray diffraction studies of a mosquito-larvicidal toxin from Bacillus thuringiensis subsp. israelensis.
abstract: The Cry4B delta-endotoxin from Bacillus thuringiensis subsp. israelensis is specifically toxic to mosquito larvae. For a better understanding of the mechanism of toxicity, chymotrypsin-activated Cry4B toxin (68 kDa) has been purified and crystallized in sodium bromide at neutral pH. The well formed crystals belong to the rhombohedral space group R32, with unit-cell parameters a = b = 185.82, c = 187.93 A, and diffracted X-rays to 1.75 A resolution. The asymmetric unit contains one toxin molecule and 74% solvent content, as shown by molecular replacement from a composite model of the homologous Cry3A and Cry1Aa. The purified protein and crystals both possessed mosquitocidal activity.
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, England. mbpbs@mahidol.ac.th
authors.forename: Panadda
authors.initials: P
authors.lastname: Boonserm
authors.forename: David J
authors.initials: DJ
authors.lastname: Ellar
authors.forename: Jade
authors.initials: J
authors.lastname: Li
mesh_terms: D000330:Aedes; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D001427:Bacterial Toxins; D002853:Chromatography, Liquid; D002918:Chymotrypsin / Q000737:chemistry; D003460:Crystallization; D009033:Culicidae / Q000502:physiology*; D004731:Endotoxins / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D006460:Hemolysin Proteins; D007306:Insecticides / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D007814:Larva; D014961:X-Ray Diffraction
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D002918:Chymotrypsin