N-ACETYL GALACTOSAMINE IS PART OF THE RECEPTOR IN INSECT GUT EPITHELIA THAT RECOGNIZES AN INSECTICIDAL PROTEIN FROM BACILLUS-THURINGIENSIS
N-ACETYL GALACTOSAMINE IS PART OF THE RECEPTOR IN INSECT GUT EPITHELIA THAT RECOGNIZES AN INSECTICIDAL PROTEIN FROM BACILLUS-THURINGIENSIS
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DOI：
10.1098/rspb.1991.0084
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发表时间：
1991-07-22
影响因子：
4.7
通讯作者：
ELLAR, DJ
中科院分区：
文献类型：
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作者：
KNOWLES, BH;KNIGHT, PJK;ELLAR, DJ
由苏云金芽孢杆菌合成的蛋白质是有效的杀虫剂。当被易感幼虫摄入时，它们迅速溶解中肠的上皮细胞。在体外的毒素裂解某些昆虫细胞系，并显示饱和，高亲和力结合刷状缘膜囊泡（BBMVS）从昆虫中肠制备。我们观察到糖N-乙酰半乳糖胺（GalNAc）特异性地降低CryIA（c）毒素对Choristoneura fumiferana CF 1细胞的细胞溶解活性，完全消除毒素与烟草天蛾BBMV的结合，部分抑制与烟芽夜蛾BBMV的结合，并且对与菜青虫BBMV的结合没有明显影响。在配体印迹实验中，毒素与M. sexta的蛋白质分子量约为125 kDa，而H.玉米毒素结合这些蛋白质的特异性抑制GalNAc。对M. sexta和H.玉米也结合凝集素大豆凝集素。综合这些发现表明，N-乙酰半乳糖胺可能是CF1细胞和至少两种测试昆虫的CryIA（c）毒素受体的组分。
Proteins synthesized by the bacterium Bacillus thuringiensis are potent insecticides. When ingested by susceptible larvae they rapidly lyse epithelial cells lining the midgut. In vitro the toxins lyse certain insect cell lines and show saturable, high-affinity binding to brush-border membrane vesicles (BBMVS) prepared from insect midguts. We observed that the sugar N-acetyl galactosamine (GalNAc) specifically decreased the cytolytic activity of a CryIA (c) toxin towards Choristoneura fumiferana CF1 cells, completely abolished toxin binding to Manduca sexta BBMVs, partially inhibited binding to Heliothis virescens BBMVs and had no apparent effect on binding to Pieris brassicae BBMVs. In ligand blotting experiments the toxin bound proteins of 120 kDa in M. sexta, 125 kDa in P. brassicae and numerous proteins in H. zea. Toxin binding to these proteins was specifically inhibited by GalNAc. The toxin binding proteins of M. sexta and H. zea also bound the lectin soybean agglutinin. Taken together these findings suggest that N-acetyl galactosamine might be a component of a CryIA (c) toxin receptor of CF1 cells and of at least two of the insects tested.