Binding and Synergizing Motif within Coleopteran Cadherin Enhances Cry3Bb Toxicity on the Colorado Potato Beetle and the Lesser Mealworm
Binding and Synergizing Motif within Coleopteran Cadherin Enhances Cry3Bb Toxicity on the Colorado Potato Beetle and the Lesser Mealworm
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DOI：
10.3390/toxins11070386
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发表时间：
2019-07
期刊：
影响因子：
4.2
通讯作者：
Young-jin Park;G. Hua;S. Ambati;Milton D. Taylor;M. Adang
中科院分区：
文献类型：
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作者：
Young-jin Park;G. Hua;S. Ambati;Milton D. Taylor;M. Adang
来自苏云金芽孢杆菌的Cry3Bb毒素是一种重要的杀虫蛋白，由于其对鞘翅目害虫特别是根虫的效力。昆虫中肠上皮细胞中的钙粘蛋白是Cry毒素的受体;在一些昆虫物种中，钙粘蛋白的毒素结合结构域协同Cry毒性。先前，我们报道了玉米根萤叶甲钙粘蛋白样蛋白的DvCad1-CR8 - 10片段（GenBank登录号EF531715）增强了Cry3Bb对科罗拉多马铃薯甲虫（CPB）、马铃薯叶甲（Leptinotarsa decimlineata（L. decimlineata）。我们报告发现DvCad1-CR8 - 10片段的各个CR结构域与α-胰凝乳蛋白酶处理的Cry3Bb具有强结合亲和力。Cry3Bb与CR8、CR9和CR10结构域结合的解离常数（Kd）分别为4.9 nM、28.2 nM和4.6 nM。CR8和CR10增强了Cry3Bb对L. decimlineata和小黄粉虫Alphitobius diaperinus新生儿。DvCad1-CR10开放阅读框的框内缺失定义了与残基I1226-D1278中的基序的高亲和力结合和协同位点。从CR10的高亲和力Cry3Bb结合区的26个氨基酸的肽作为Cry3Bb抑制剂对鞘翅目幼虫起作用。
Cry3Bb toxin from Bacillus thuringiensis is an important insecticidal protein due to its potency against coleopteran pests, especially rootworms. Cadherin, a protein in the insect midgut epithelium, is a receptor of Cry toxins; in some insect species toxin-binding domains of cadherins-synergized Cry toxicity. Previously, we reported that the DvCad1-CR8-10 fragment of Diabrotica virgifera virgifera cadherin-like protein (GenBank Accession #EF531715) enhanced Cry3Bb toxicity to the Colorado Potato Beetle (CPB), Leptinotarsa decimlineata (L. decimlineata). We report that individual CR domains of the DvCad1-CR8-10 fragment were found to have strong binding affinities to α-chymotrypsin-treated Cry3Bb. The dissociation constant (Kd) of Cry3Bb binding to the CR8, CR9, and CR10 domain was 4.9 nM, 28.2 nM, and 4.6 nM, respectively. CR8 and CR10, but not CR9, enhanced Cry3Bb toxicity against L. decimlineata and the lesser mealworm Alphitobius diaperinus neonates. In-frame deletions of the DvCad1-CR10 open reading frame defined a high-affinity binding and synergistic site to a motif in residues I1226–D1278. A 26 amino acid peptide from the high affinity Cry3Bb-binding region of CR10 functioned as a Cry3Bb synergist against coleopteran larvae.