Characterization of cry1Cb3 and cry1Fb7 from Bacillus thuringiensis subsp. galleriae

Abstract

Two cry1-type genes encoding insecticidal crystal proteins (ICPs) were detected by PCR-RFLP and cloned from Bacillus thuringiensis subsp. galleriae 87. The nucleotide sequences were deposited in GenBank with accession numbers EU679501 and EU679502, and designated as cry1Fb7 and cry1Cb3 respectively by B. thuringiensis Delta- Endotoxin Nomenclature Committee. cry1Cb3 shared 99% homology with other cry1Cb genes. The existence of two additional stop codons indicated cry1Cb3 was a silent gene. The cry1Cb3 was 3531 bp with 38.98% G+C content and its first open reading frame (ORF) encoded a protein of 213 amino acid residues with a calculated molecular weight of 23.8 kDa and a predicted pI value of 4.63. Five amino acid sequence blocks (block 1, block 2, block 3, block 4 and block 5) were found in Cry1Cb3. Translation of cry1Fb7 revealed an ORF of 3525 bp with 39.12% G+C content and a protein with a calculated molecular weight of 133.2 kDa and a predicted pI value of 5.18. Cry1Fb7 had five amino acid sequence blocks (blocks 1, 2, 3, 4 and 5) and three domains (I, II and III), which consisted of 218 residues (Leu34 to Ala252), 197 residues (Thr257 to Asp454), and 138 residues (Ile464 to Glu600), respectively.