Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN, 46268, USA.
Sci Rep. 2017 Sep 11;7(1):11112. doi: 10.1038/s41598-017-11702-2.
In this work, we characterized 2 novel insecticidal proteins; Vip3Ab1 and Vip3Bc1. These proteins display unique insecticidal spectra and have differential rates of processing by lepidopteran digestive enzymes. Furthermore, we have found that both proteins exist as tetramers in their native state before and after proteolysis. In addition, we expressed truncated forms and protein chimeras to gain a deeper understanding of toxin specificity and stability. Our study confirms a role for the C-terminal 65 kDa domain in directing insect specificity. Importantly, these data also indicate a specific interaction between the 20 kDa amino terminus and 65 kDa carboxy terminus, after proteolytic processing. We demonstrate the C-terminal 65 kDa to be labile in native proteolytic conditions in absence of the 20 kDa N-terminus. Thus, the 20 kDa fragment functions to provide stability to the C-terminal domain, which is necessary for lethal toxicity against lepidopteran insects.
在这项工作中，我们对 2 种新型杀虫蛋白（Vip3Ab1 和 Vip3Bc1）进行了特征描述。这些蛋白显示出独特的杀虫谱，并且对鳞翅目消化酶的加工速度存在差异。此外，我们发现这两种蛋白在原态和酶解后均以四聚体形式存在。此外，我们还表达了截断形式和蛋白嵌合体，以更深入地了解毒素的特异性和稳定性。我们的研究证实了 C 端 65 kDa 结构域在指导昆虫特异性方面的作用。重要的是，这些数据还表明，在没有 20 kDa N 端的情况下，在原态酶解条件下，20 kDa 氨基末端和 65 kDa 羧基末端之间存在特定的相互作用。我们证明，在缺乏 20 kDa N 端的情况下，C 端 65 kDa 结构域在原态酶解条件下不稳定。因此，20 kDa 片段的功能是为 C 端结构域提供稳定性，这对于针对鳞翅目昆虫的致死毒性是必要的。
