[Cloning and comparative characteristics of genes coding two structurally distant delta-endotoxins of Bacillus...

Representative total DNA libraries of Bac. thuringiensis var. kurstaki (strain Dipel) and galleriae (strain 11-67) have been constructed on the basis of phasmid vector lambda pSL5. Recombinant phasmid clones, carrying delta-endotoxin-coding genes of both subspecies have been isolated by means of immunoenzyme screening. Restriction mapping and partial nucleotide sequence determination have demonstrated that phasmid lambda pOC2, isolated from var. kurstaki DNA library, contains the complete delta-endotoxin-coding gene, identical to the one, described by Schnepf H.E. et al. J. Biol. Chem. 1985. V. 260. P. 6264. Recombinant phasmids lambda pOC10 and 11 have been shown to contain the full-sized gene, coding delta-endotoxin of Bac. thuringiensis var. galleriae. The protein products of the cloned genes have been characterized by Western-blot analysis and bioassays. The absence of substantial homology of two genes, evidenced by Southern-blot hybridisation, correlates with sufficiently big differences in biological specificity of the corresponding proteins. This is in accordance with our previous data on N-terminal amino acid sequence determination of delta-endotoxins of those subspecies of Bac. thuringiensis.