Nucleic acid compositions encoding modified Bacillus thuringiensis coleopteran-toxic crystal proteins
AssigneeMonsanto Technology LLC
InventorsLeigh H. English, Susan M. Brussock, Thomas M. Malvar, James W. Bryson, Caroline A. Kulesza, Frederick S. Walters, Stephen L. Slatin, Michael A. Von Tersch, Charles Romano
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Abstract
Disclosed are nucleic acid segments comprising synthetically-modified genes encoding Coleopteran-toxic B. thuringiensis δ-endotoxins. Also disclosed are methods of using these genes for the recombinant expression of polypeptides, the preparation of vectors containing the genes, and methods for transforming suitable host cells.
Claims21
An isolated nucleic acid segment comprising a modified cry3Bb* gene encoding a modified Cry3Bb* polypeptide, said modified polypeptide comprising one or more point mutations in or near α helix 4, wherein said one or more point mutations result in at least one amino acid substitution selected from the group consisting of Leu158 to Arg, Ser160 to Asn, Lys161 to Pro, Pro162 to His, Asp165 to Gly, and Lys189 to Gly.
An isolated nucleic acid segment comprising a modified cry3Bb* gene encoding a modified Cry3Bb* polypeptide comprising the substitutions His231 to Arg, Ser311 to Leu, Asn313 to Thr, Glu317 to Lys, and Gln348 to Arg.
A method of preparing a modified Cry3Bb* polypeptide having improved insecticidal activity relative to the insecticidal activity of an unmodified Cry3Bb polypeptide, wherein the method comprises the steps of:
- (a) providing an isolated nucleic acid segment comprising a modified cry3Bb* gene encoding a modified Cry3Bb” polypeptide, wherein said modified polypeptide comprises one or more point mutations in or near α helix 4, wherein said one or more point mutations result in at least one amino acid substitution selected from the group consisting of Leu158 to Arg, Ser160 to Asn, Lys161 to Pro, Pro162 to His, Asp165 to Gly, and Lys189 to Gly;
- wherein said modified cry3Bb* gene is operably linked to a promoter;
- and
- wherein said nucleic acid segment and said promoter are in a vector;
- (b) transforming a host cell with said vector;
- (c) culturing said host cell under conditions effective to allow expression of the modified Cry3Bb* polypeptide, and
- (d) isolating the modified Cry3Bb* polypeptide thus produced.
Dependencies are inferred from the claim text.