Radboud University Nijmegen, Institute for Molecules and Materials, Cluster of Organic Chemistry, Nijmegen, The Netherlands.
Bioorg Med Chem Lett. 2013 Sep 15;23(18):5182-6. doi: 10.1016/j.bmcl.2013.07.004. Epub 2013 Jul 13.
Strigolactones (SLs) are new plant hormones with varies important bio-functions. This Letter deals with germination of seeds of parasitic weeds. Natural SLs have a too complex structure for synthesis. Therefore, there is an active search for SL analogues and mimics with a simpler structure with retention of activity. SL analogues all contain the D-ring connected with an enone moiety through an enol ether unit. A new mechanism for the hydrolysis SL analogues involving bidentate bound water and an α,β-hydrolase with a Ser-His-Asp catalytic triad has been proposed. Newly discovered SL mimics only have the D-ring with an appropriate leaving group at C-5. A mode of action for SL mimics was proposed for which now supporting evidence is provided. As predicted an extra methyl group at C-4 of the D-ring blocks the germination of seeds of parasitic weeds.
独脚金内酯是具有各种重要生物功能的新型植物激素。这封信涉及寄生杂草种子的萌发。天然独脚金内酯的结构过于复杂，无法进行合成。因此，人们积极寻找结构更简单但保留活性的独脚金内酯类似物和模拟物。独脚金内酯类似物都含有 D 环，通过烯醇醚单元与 C-2 位上的烯酮部分连接。提出了一种新的独脚金内酯类似物水解机制，涉及桥连双配位水分子和具有 Ser-His-Asp 催化三联体的α,β-水解酶。新发现的独脚金内酯模拟物仅在 D 环的 C-5 位上具有适当的离去基团。提出了独脚金内酯模拟物的作用模式，现在提供了支持该模式的证据。正如预测的那样，D 环 C-4 位上的额外甲基基团阻止了寄生杂草种子的萌发。
