Formation of macromolecule complex with bacillus thuringiensis Cry1A toxins and chlorophyllide binding 252-kDa lipocalin-like protein locating on bombyx mori midgut membrane
P252, a 252-kDa Bombyx mori protein located on the larval midgut membrane, has been shown to bind strongly with Bacillus thuringiensis Cry1A toxins (Hossain et al. Appl Environ Microbiol 70:4604-4612, 2004). P252 was also shown to bind chlorophyllide (Chlide) to form red fluorescence-emitting comple...
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| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Published: |
2018
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| Online Access: | https://repository.li.mahidol.ac.th/handle/123456789/28625 |
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| Institution: | Mahidol University |
| Summary: | P252, a 252-kDa Bombyx mori protein located on the larval midgut membrane, has been shown to bind strongly with Bacillus thuringiensis Cry1A toxins (Hossain et al. Appl Environ Microbiol 70:4604-4612, 2004). P252 was also shown to bind chlorophyllide (Chlide) to form red fluorescence-emitting complex Bm252RFP with significant antimicrobial activity (Pandian et al. Appl Environ Microbiol 74:1324-1331, 2008). In this article, we show that Cry1A toxin bound with Bm252RFP and Bm252RFP-Cry1A macrocomplex, with both antimicrobial and insecticidal activities, was formed. The insecticidal activity of Bm252RFP-Cry1Ab was reduced from an LD50 of 1.62 to 5.05 μg, but Bm252RFP-Cry1Aa and Bm252RFP-Cry1Ac did not show such reduction. On the other hand, the antimicrobial activity of Bm252RFP-Cry1Ab was shown to retain almost the same activity as Bm252RFP, while the other two complexes lost around 30% activity. The intensity of photo absorbance and fluorescence emission of Bm252RFP-Cry1Ab were significantly reduced compared to those of the other two complexes. Circular dichroism showed that the contents of Cry1Ab α-helix was significantly decreased in Bm252RFP-Cry1Ab but not in the other two toxins. These data suggested that the reduction of contents of α-helix in Cry1Ab affected the insecticidal activity of the macrocomplex but did not alter the antimicrobial moiety in the macrocomplex of Bm252RFP-Cry1Ab. © 2010 Springer Science+Business Media, LLC. |
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