AI Article Synopsis
- Cry2Aa is effective against both Lepidoptera (moths and butterflies) and Diptera (flies), while Cry2Ab primarily targets Lepidoptera and lacks activity against mosquitoes.
- Cry2Ab differs from Cry2Aa by 13% in amino acid sequence and has been shown to be toxic to Anopheles gambiae (a malaria-carrying mosquito), with a lethal concentration of 540 ng/mL.
- Mutagenesis experiments on Cry2Ab identified key amino acids responsible for its function and highlighted potential to enhance its insecticidal properties, suggesting that Cry2Ab should be considered a dual-active Cry toxin.
Article Abstract
Cry2Aa exhibits dual activity to Lepidoptera and Diptera. Cry2Ab differs in amino acid sequence from Cry2Aa by 13% and has shown significant lepidopteran activity, but no mosquitocidal activity. Previous studies implicate 23 Cry2Aa specificity-conferring residues of domain II, which differ in Cry2Ab. Nine residues are putatively involved in conferring Cry2Aa dipteran specificity. To explore Cry2Ab dipteran toxicity, site-directed mutagenesis was employed to exchange Cry2Ab residues with Cry2Aa D (dipteran) block residues. Cry2Ab wild type demonstrated high toxicity (LC(50) of 540 ng mL(-1)) to Anopheles gambiae, but not to Aedes or Culex, within a 24-h time period. Cry2Ab should be reclassified as a dual active Cry toxin. Cry2Ab mutagenesis revealed critical residues for Cry2Ab protein function, as well as enhanced activity against the malarial mosquito, An. gambiae.
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| http://dx.doi.org/10.1111/j.1574-6968.2011.02403.x | DOI Listing |
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