4-Coumaroyl-CoA ligase (4CL) is ubiquitous in the plant kingdom, and plays a central role in the biosynthesis of phenylpropanoids such as lignins, flavonoids, and coumarins. 4CL catalyzes the formation of the coenzyme A thioester of cinnamates such as 4-coumaric, caffeic, and ferulic acids, and the regulatory position of 4CL in the phenylpropanoid pathway renders the enzyme an attractive target that controls the composition of phenylpropanoids in plants. In this study, we designed and synthesized mechanism-based inhibitors for 4CL in order to develop useful tools for the investigation of physiological functions of 4CL and chemical agents that modulate plant growth with the ultimate goal to produce plant biomass that exhibits features that are beneficial to humans. The acylsulfamide backbone of the inhibitors in this study was adopted as a mimic of the acyladenylate intermediates in the catalytic reaction of 4CL. These acylsulfamide inhibitors and the important synthetic intermediates were fully characterized using two-dimensional NMR spectroscopy. Five 4CL proteins with distinct substrate specificity from four plant species, i.e., Arabidopsis thaliana, Glycine max (soybean), Populus trichocarpa (poplar), and Petunia hybrida (petunia), were used to evaluate the inhibitory activity, and the half-maximum inhibitory concentration (IC₅₀) of each acylsulfamide in the presence of 4-coumaric acid (100 µM) was determined as an index of inhibitory activity. The synthetic acylsulfamides used in this study inhibited the 4CLs with IC₅₀ values ranging from 0.10 to 722 µM, and the IC₅₀ values of the most potent inhibitors for each 4CL were 0.10–2.4 µM. The structure–activity relationship observed in this study revealed that both the presence and the structure of the acyl group of the synthetic inhibitors strongly affect the inhibitory activity, and indicates that 4CL recognizes the acylsulfamide inhibitors as acyladenylate mimics.

4-香豆酰辅酶A连接酶（4CL）在植物界中普遍存在，在木质素、类黄酮和香豆素等苯丙素类化合物的生物合成中发挥着核心作用。 4CL 催化肉桂酸（例如 4-香豆酸、咖啡酸和阿魏酸）的辅酶 A 硫酯的形成，并且 4CL 在苯丙素途径中的调节位置使该酶成为控制植物中苯丙素组成的有吸引力的靶标。在这项研究中，我们设计并合成了基于机制的 4CL 抑制剂，以开发有用的工具来研究 4CL 的生理功能和调节植物生长的化学试剂，最终目标是产生具有有益于植物生长特征的植物生物量。人类。本研究中抑制剂的酰基磺酰胺骨架被用作 4CL 催化反应中酰基腺苷酸中间体的模拟物。使用二维核磁共振波谱对这些酰基磺酰胺抑制剂和重要的合成中间体进行了充分表征。使用来自四种植物即拟南芥、大豆（大豆）、毛果杨（杨）和矮牵牛（矮牵牛）的五种具有不同底物特异性的4CL蛋白来评估抑制活性和半最大抑制将4-香豆酸(100μM)存在下的各酰基磺酰胺的浓度(IC ₅₀ )确定为抑制活性的指标。本研究中使用的合成酰基磺酰胺抑制 4CL，IC ₅₀值范围为 0.10 至 722 µM，每种 4CL 最有效的抑制剂的 IC ₅₀值为 0.10–2.4 µM。 本研究中观察到的结构-活性关系表明，合成抑制剂的酰基的存在和结构都会强烈影响抑制活性，并表明 4CL 将酰基磺酰胺抑制剂识别为酰基腺苷酸模拟物。