CHEMICAL MODIFICATION OF BACILLUS-THURINGIENSIS ACTIVATED DELTA-ENDOTOXIN AND ITS EFFECT ON TOXICITY AND BINDING TO MANDUCA-SEXTA MIDGUT MEMBRANES
CHEMICAL MODIFICATION OF BACILLUS-THURINGIENSIS ACTIVATED DELTA-ENDOTOXIN AND ITS EFFECT ON TOXICITY AND BINDING TO MANDUCA-SEXTA MIDGUT MEMBRANES
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DOI：
10.1099/00221287-140-10-2737
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发表时间：
1994-10-01
期刊：
影响因子：
2.8
通讯作者：
ELLAR, DJ
中科院分区：
文献类型：
--
作者：
CUMMINGS, CE;ELLAR, DJ
研究了苏云金芽孢杆菌杀虫CrylA(c)毒素芳香残基和碱性残基的化学修饰对毒力和受体结合的影响。对43种精氨酸残基中的4种或4种以上进行修饰，可在体内消除对雌雄小蠊（Manduca sexta）和芸苔虫（Pieris brassicae）的毒性，并在体外消除对富氏毛线虫（Choristoneura fumiferana）细胞系的毒性。对27个酪氨酸残基中的7个或更多进行修饰可降低毒性。对10种色氨酸残基中的大部分进行修饰后，毒性降低。组氨酸残基的修饰对毒性无影响。建立并优化了一种与天然毒素衍生物结合的定量分析方法，以比较其与草属植物毛囊的结合情况。选择性修饰酪氨酸或精氨酸残基所观察到的毒性的降低或消除反映在衍生物的结合能力上。但是一种无毒的衍生物。在色氨酸残基上进行了修饰，保留了结合囊泡的能力。这些结果表明，酪氨酸和精氨酸残基参与了毒素与受体的结合相互作用，而色氨酸残基则参与了一些后续步骤。
The effect of chemical modification of aromatic and basic residues of the Bacillus thuringiensis insecticidal CrylA(c) toxin on toxicity and receptor binding was studied. Modification of four or more of the 43 arginine residues resulted in abolition of toxicity towards Manduca sexta and Pieris brassicae in vivo and a Choristoneura fumiferana cell line in vitro. Modification of seven or more of the 27 tyrosine residues resulted in reduction of toxicity. Upon modification of most of the 10 tryptophan residues, toxicity was reduced. Modification of histidine residues had no effect on toxicity. A quantitative binding assay was developed and optimized to compare the binding of derivatives with native toxin to M. sexta brush border membrane vesicles. The reduction or abolition of toxicity observed upon selective modification of tyrosine or arginine residues was reflected in the binding abilities of the derivatives. However a non-toxic derivative. modified at tryptophan residues, retained its ability to bind vesicles. These results suggest that tyrosine and arginine residues are involved in the binding interaction of toxin with receptor but tryptophan residues are involved in some subsequent step.