DestruxinA,一种由绿僵菌产生的非核糖体肽毒素,通过靶向各种组织表现出有效的杀虫活性,器官,和昆虫的细胞。我们先前的研究表明,DA具有与多种蛋白质结合的能力。在这项研究中,我们旨在鉴定DA最敏感的结合蛋白,并研究DA调节的生理过程。通过RNAi技术,我们在家蚕血淋巴中筛选了22种DA结合蛋白。其中,幼体激素结合蛋白(JHBP),一种对生长和发育调节至关重要的激素转运蛋白,对DA的敏感性最高。随后的实验表明,DA可以抑制家蚕幼虫的体重增加,加速化蛹的发生,并调节血淋巴中游离保幼激素(JH)的含量。我们还观察到DA可以诱导JHBP和JHBP-JH结合复合物的构象变化。值得注意的是,在低剂量下,DA影响JHBP与JH的结合,而在高剂量下,它不可逆转地影响了JHBP与JH的结合。分子对接和点突变实验表明,DA可能会影响JHBP的N臂,负责JH绑定。此外,我们发现JHBP广泛分布在家蚕的各种组织中,包括表皮,gut,gut脂肪的身体,Malpighian小管,性腺,肌肉,气管,和血细胞。这项研究为DA的杀虫机制提供了新的见解,并增强了我们对绿僵菌致病过程的理解。
Destruxin A, a non-ribosomal peptide toxin produced by Metarhizium, exhibits potent insecticidal activity by targeting various tissues, organs, and cells of insects. Our previous research has revealed that DA possesses the ability to bind to multiple proteins. In this study, we aimed to identify the most sensitive binding proteins of DA and investigate the physiological processes in which DA regulated. Through RNAi technology, we screened 22 binding proteins of DA in silkworm hemolymph. Among them, the juvenile hormone binding protein (JHBP), a hormone transport protein crucial for growth and development regulation, exhibited the highest sensitivity to DA. Subsequent experiments demonstrated that DA could inhibit the body weight gain of silkworm larvae, accelerate the pupation occurrence, and modulate the content of free juvenile hormone (JH) in the hemolymph. We also observed that DA could induce conformational changes in both the JHBP and the JHBP-JH binding complex. Notably, at low dosage, DA influenced the binding of JHBP to JH, while at high dosage, it irreversibly affected the binding of JHBP to JH. Molecular docking and point-mutant experiments suggested that DA might affect the N-arm of JHBP, which is responsible for JH binding. Additionally, we discovered that JHBP is widely distributed in various tissues of the silkworm, including the epidermis, gut, fat body, Malpighian tubule, gonad, muscle, trachea, and hemocyte. This study provides novel insights into the insecticidal mechanism of DA and enhances our understanding of the pathogenic process of Metarhizium.