Cry1Aa binding to the cadherin receptor does not require conserved amino acid sequences in the domain II loops.
Cry1Aa binding to the cadherin receptor does not require conserved amino acid sequences in the domain II loops.
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DOI：
10.1042/bsr20120113
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发表时间：
2012-12-20
影响因子：
4
通讯作者：
Sato R
中科院分区：
文献类型：
--
作者：
Fujii Y;Tanaka S;Otsuki M;Hoshino Y;Morimoto C;Kotani T;Harashima Y;Endo H;Yoshizawa Y;Sato R
表征 Bt（苏云金芽孢杆菌）Cry 毒素与钙粘蛋白受体的结合机制对于了解该毒素的特定杀虫活性至关重要。为此，我们通过随机插入覆盖所有四个受体结合环（环α8、1、2和3）的四个连续氨基酸构建了30个环突变体，并通过Biacore分析了它们与家蚕钙粘蛋白受体的结合亲和力。证实所有 30 个含有与野生型不同的环序列的突变体具有高结合亲和力。至少在环 1、2 和 3 的一种突变体中证实了杀虫活性，这表明四个环与 BtR175 的结合没有关键的氨基酸序列。当不同环处的两个突变整合到一个分子中时，与野生型序列相比，没有观察到结合亲和力的降低。基于这些结果，我们讨论了Cry毒素与钙粘蛋白的结合机制。
Characterizing the binding mechanism of Bt (Bacillus thuringiensis) Cry toxin to the cadherin receptor is indispensable to understanding the specific insecticidal activity of this toxin. To this end, we constructed 30 loop mutants by randomly inserting four serial amino acids covering all four receptor binding loops (loops α8, 1, 2 and 3) and analysed their binding affinities for Bombyx mori cadherin receptors via Biacore. High binding affinities were confirmed for all 30 mutants containing loop sequences that differed from those of wild-type. Insecticidal activities were confirmed in at least one mutant from loops 1, 2 and 3, suggesting that there is no critical amino acid sequence for the binding of the four loops to BtR175. When two mutations at different loops were integrated into one molecule, no reduction in binding affinity was observed compared with wild-type sequences. Based on these results, we discussed the binding mechanism of Cry toxin to cadherin protein.