中国科学C辑(英文版)
中國科學C輯(英文版)
중국과학C집(영문판)
SCIENCE IN CHINA (Series C)
2002年
6期
561-568
,共8页
苏彦辉%曲红%Vachon Vincent%罗静初%张杰%Laprade Raynald%朱玉贤
囌彥輝%麯紅%Vachon Vincent%囉靜初%張傑%Laprade Raynald%硃玉賢
소언휘%곡홍%Vachon Vincent%라정초%장걸%Laprade Raynald%주옥현
Bt toxin proteins%light scattered assay%ion channel%molecular model
Development of targeted biological agents against agricultural insect pests is of prime importance for the elaboration and implementation of integrated pest management strategies that are environment-friendly, respectful of bio-diversity and safer to human health through reduced use of chemical pesticides. A major goal to understand how Bt toxins work is to elucidate the functions of their three domains. Domains II and III are involved in binding specificity and structural integrity, but the function of Domain I remains poorly understood. Using a Manduca sexta BBMV (brush border membrane vesicles) system, we analyzed its responses to Cry1Aa 15 single-point mutations with altered Domain I helix 4 residues. Light scattering assay showed that toxicity was almost lost in 3 mutants, and we observed significantly reduced toxicity in other 7 mutants. However, 5 mutants retained wild-type toxicity. Using computer software, we simulated the three-dimensional structures of helix 4. Both experimental and bioinformatic analysis showed that residues in Cry1Aa Domain I helix 4 were involved in the formation of ion channels that is critical for its insect toxicity.