Functional analysis of two processed fragments of Bacillus thuringiensis Cry11A toxin.
The 70-kDa protoxin of Cry11A, a dipteran-specific insecticidal protein, was processed by trypsin into 36- and 32-kDa fragments. To investigate the potent function of the two processed fragments, a GST (Glutathione-S-transferase) fusion protein of each polypeptide was constructed. While neither the 36- nor the 32-kDa fragment was toxic to Culex pipiens larvae, coexpression of the two fragments restored the insecticidal activity. Furthermore, the coprecipitation experiment demonstrated that the 36-kDa fragment was associated with the 32-kDa fragment. It was, therefore, shown that the coexistence of the two processed fragments of Cry11A was essential for the toxicity. The mutant of the 36-kDa fragment lacking the region from Gly(257) to Arg(360) bound to the 32-kDa fragment but the coexpression with the 32-kDa fragment resulted in no toxicity, suggesting that this region was involved in insecticidal activity.
Yamagiwa
Masashi
M
Department of Bioscience and Biotechnology, Okayama University, Japan.
Sakagawa
Kohei
K
Sakai
Hiroshi
H
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000633:toxicity*; D001427:Bacterial Toxins / Q000737:chemistry* / Q000235:genetics / Q000633:toxicity*; D001681:Biological Assay; D003465:Culex / Q000187:drug effects*; D004731:Endotoxins / Q000737:chemistry* / Q000235:genetics / Q000633:toxicity*; D005982:Glutathione Transferase / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D006460:Hemolysin Proteins; D007306:Insecticides / Q000737:chemistry* / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D009154:Mutation; D010449:Peptide Mapping; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics / Q000633:toxicity; D014357:Trypsin / Q000737:chemistry
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D011993:Recombinant Fusion Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D005982:Glutathione Transferase; D014357:Trypsin