家蚕保幼激素酸甲基转移酶BmJHAMTs的结构解析与功能研究

保幼激素(Juvenile Hormone, JH)是调控昆虫变态发育的重要激素，它的合成途径也因此成为研究昆虫发育的热点和探索害虫控制的重要靶点。保幼激素酸甲基转移酶JHAMT是JH合成过程的关键酶，学界普遍认为JHAMT只在昆虫的咽侧体中参与JH合成。而近期的研究发现昆虫体内存在很多JHAMT的同源蛋白，它们在外周组织中也有表达，但参与的生理功能还不清楚。本项目瞄准家蚕保幼激素酸甲基转移酶BmJHAMTs家族，通过解析BmJHAMT的三维结构，并结合生化分析从原子水平阐释BmJHAMT的活性位点及酶活机制；寻找昆虫JHAMT识别底物的结构学基础和通用规律，为抗JH类抑制剂设计提供理论指导。同时，系统鉴定BmJHAMTs各成员的时空表达谱，并结合BmJHAMTs体内和体外的活性分析，阐释BmJHAMTs各成员在JH合成及组织发育过程中作用机理，揭示昆虫JHAMT参与JH合成的新途径。

Juvenile hormone (JH) is an important sesquiterpenoid that regulate many aspects of insect physiology, including development, reproduction, diapause, and polyphenisms. Thus, the biosynthesis of JH has become a hotspot for insect development research and the pest control exploration. The juvenile hormone acid methyltransferase (JHAMT) is the key enzyme for the biosynthesis process, and it was generally considered to be involved in JH synthesis only in the corpus allatum. However, recent studies suggested that JHAMT from some insect was also expressed in other tissues and participated in the production of JH. The present project will focus on the JHAMT family from silkworm, Bombyx mori. The structures of apo-BmJHAMTs and the complex of BmJHAMTs with substrate will be determined by crystallography. The structural analysis combined with the biochemical analysis will be performed to clarify the relationship between structural basis and enzymatic mechanism of JHAMT. Furthermore, the substrate binding sites of JHAMT from various insect will be compared by structural and bioinformatics analysis, which will provide theoretical guidance for the design of anti-JH biological pesticide. In addition, we will systematically identify the expression characterization and localization of each BmJHAMT gene, which would help us to figure out the temporal and spatial expression profiles of BmJHAMTs. Moreover, the activities of natural BmJHAMTs from different tissues and the recombinant BmJHAMTs will be detected, respectively. The expression profiles and activities analysis will elucidate the function of each BmJHAMT in the process of JH production and tissue development, and reveal if the JH can be synthesized in the peripheral tissues by JHAMT.