title: Formation of macromolecule complex with Bacillus thuringiensis Cry1A toxins and chlorophyllide binding 252-kDa lipocalin-like protein locating on Bombyx mori midgut membrane.
abstract: 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.
authors.affiliation: Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan.
authors.forename: Ganesh N
authors.initials: GN
authors.lastname: Pandian
authors.forename: Toshiki
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Thangavel
authors.initials: T
authors.lastname: Vaijayanthi
authors.forename: Delwar M
authors.initials: DM
authors.lastname: Hossain
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Nishiumi
authors.forename: Chanan
authors.initials: C
authors.lastname: Angsuthanasombat
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Haginoya
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Mitsui
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Hori
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism / Q000494:pharmacology; D015153:Blotting, Western; D012831:Bombyx / Q000187:drug effects* / Q000378:metabolism*; D002735:Chlorophyllides / Q000378:metabolism*; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D004731:Endotoxins / Q000378:metabolism / Q000494:pharmacology; D006460:Hemolysin Proteins / Q000378:metabolism / Q000494:pharmacology; D019476:Insect Proteins / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism / Q000494:pharmacology*; D054834:Lipocalins / Q000378:metabolism*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D002735:Chlorophyllides; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D007306:Insecticides; D054834:Lipocalins; C030956:insecticidal crystal protein, Bacillus Thuringiensis