Hedycaryol Synthase in Complex with Nerolidol Reveals Terpene Cyclase Mechanism
Hedycaryol Synthase in Complex with Nerolidol Reveals Terpene Cyclase Mechanism
复制标题
DOI：
10.1002/cbic.201300708
复制
发表时间：
2014-01-24
期刊：
影响因子：
3.2
通讯作者：
Dickschat, Jeroen S.
中科院分区：
文献类型：
--
作者：
Baer, Philipp;Rabe, Patrick;Dickschat, Jeroen S.
萜烯的生物合成是由I类和II类萜类环酶催化的。在这里，我们提供了I类己内酯合成酶的结构数据，它与橙花醇形成络合物，作为反应中间体橙花酯二磷酸的替代品。这个预折叠的配体允许绘制活性位点的图谱，从而识别Val179的关键羰基氧、高度保守的螺旋断裂(G1/2)及其相应的螺旋偶极。这些元素将碳正离子稳定在底物的C1位置，协同作用催化1，10环的闭合，从而专门产生反Markovnikov产物。通过特定部位的突变证实了一般机械支架的描述。这项工作为理解酶反应中的碳正离子化学奠定了基础，并将有助于这些酶在有机合成中的未来应用。
The biosynthesis of terpenes is catalysed by class I and II terpene cyclases. Here we present structural data from a class I hedycaryol synthase in complex with nerolidol, serving as a surrogate for the reaction intermediate nerolidyl diphosphate. This prefolded ligand allows mapping of the active site and hence the identification of a key carbonyl oxygen of Val179, a highly conserved helix break (G1/2) and its corresponding helix dipole. Stabilising the carbocation at the substrate's C1 position, these elements act in concert to catalyse the 1,10 ring closure, thereby exclusively generating the anti-Markovnikov product. The delineation of a general mechanistic scaffold was confirmed by site-specific mutations. This work serves as a basis for understanding carbocation chemistry in enzymatic reactions and should contribute to future application of these enzymes in organic synthesis.