State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing, 400716, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, China.
State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing, 400716, China.
Insect Biochem Mol Biol. 2022 Nov;150:103849. doi: 10.1016/j.ibmb.2022.103849. Epub 2022 Oct 6.
Phosphomevalonate kinase (PMK) is an important enzyme involved in the juvenile hormone (JH) biosynthesis pathway that catalyzes the phosphorylation of mevalonate 5-phosphate into mevalonate 5-diphosphate in the mevalonate pathway. Herein, we report the crystal structure of insect PMK from Bombyx mori (BmPMK) at a resolution of 1.60 Å. The overall structure of BmPMK adopts a compact α/β conformation with two parts: the core and lid regions. The interface between the core and lid regions forms a continuous and negatively charged groove to accommodate the substrates. Using computational simulation combined with site-directed mutagenesis and biochemical analysis, we define the binding mode of BmPMK with the cofactor and the substrate, which provides a structural basis for understanding the catalytic mechanism and the design of inhibitors of PMK. Moreover, BmPMK showed the optimal enzyme activity at pH 8.0, and the optimal temperature was 30 °C, using mevalonate 5-phosphate as the substrate. The expression profiles and kinetic analyses of BmPMK indicated that it plays critical role in the control of JH biosynthesis in silkworms. Collectively, these findings provide a better understanding of the structural and biochemical features of insect PMK.
磷酸甲羟戊酸激酶（PMK）是参与保幼激素（JH）生物合成途径的重要酶，它在甲羟戊酸途径中催化磷酸甲羟戊酸 5-磷酸化为甲羟戊酸 5-二磷酸。在此，我们报告了鳞翅目昆虫 PMK 来自家蚕（BmPMK）的晶体结构，分辨率为 1.60Å。BmPMK 的整体结构采用紧凑的α/β构象，分为两部分：核心和盖子区域。核心和盖子区域之间的界面形成一个连续的带负电荷的凹槽，以容纳底物。通过计算模拟结合定点突变和生化分析，我们定义了 BmPMK 与辅因子和底物的结合模式，为理解催化机制和 PMK 抑制剂的设计提供了结构基础。此外，BmPMK 以甲羟戊酸 5-磷酸为底物时，在 pH8.0 时表现出最佳的酶活性，最适温度为 30°C。BmPMK 的表达谱和动力学分析表明，它在家蚕 JH 生物合成的调控中起着关键作用。总的来说，这些发现为昆虫 PMK 的结构和生化特征提供了更好的理解。
