TRICHODIENE SYNTHASE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 三环二烯合成酶(TS)是一种依赖镁离子的倍半萜环化酶。倍半萜环化酶催化一种通用的非环底物法尼基二磷酸转化为具有精细几何和立体化学精度的众多环状和手性倍半萜碳氢化合物或醇之一。这些倍半萜是几种分子的前体，这些分子在我们的日常生活中非常重要，如抗生素、烹饪添加剂、香水等。这些分子进化成只形成三环二烯。然而，酶活性部位的保守定点突变不仅会影响酶的活性，还会使酶脱轨，产生更多与中间体更相似的产物，而不是产物或底物。因此，对这些产物的研究以及某种突变是如何使某些异常产物产生的，有助于了解这种酶的作用机制。我们正在通过研究突变的TS酶及其与各种配体的络合物来研究异常产物形成的结构基础。基于各种突变体的结构，我们发现异常产物的形成主要是活性部位的函数，活性部位不能形成一个完全定制的模板来形成三氯二烯的排他性形成。在突变体中，配体结合的活性部位的体积通常比野生型酶大得多。我们研究了一个富含天冬氨酸的基序，该基序在所有物种的倍半萜环化酶中都是保守的。我们目前正在研究第二个金属结合基序的重要性，通常被称为NSE(或DTE)基序。这些对倍半萜环化酶和其他倍半萜环化酶的研究的最终目的是能够预测给定的倍半萜环化酶的产物，并设计新的倍半萜，从而形成具有各种生物和商业应用的新倍半萜。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Trichodiene synthase (TS) is a Mg(II)-dependent sesquiterpene cyclase. Sesquiterpene cyclases catalyze the conversion of a universal acyclic substrate farnesyl diphosphate to one of numerous cyclic and chiral sesquiterpene hydrocarbons or alcohols with exquisite geometric and stereochemical precision. These sesquiterpenes are the precursors of several molecules that are of great importance to us in our everyday life as antibiotics, culinary additives, perfumes etc. TS evolved to exclusively form only trichodiene. However, conservative site-specific mutations in the active site of the enzyme not only affect the activity of the enzyme but also derail the enzyme into making additional products that resemble the intermediates more than the product or the substrate. Therefore, the study of these products and how a certain mutation makes certain aberrant products sheds light on the mechanism of the enzyme. We are studying the structural basis for aberrant product formation by the study of the mutant TS enzymes and their complexes with various ligands. Based on the structures of various mutants, we found that the aberrant product formation is mainly a function of the active site that does not form a perfectly tailored template for the exclusive formation of trichodiene. The volumes of ligand-bound active sites are generally much larger in the mutants than in the wild-type enzyme. We have studied an aspartate-rich motif that is conserved across sesquiterpene cyclases from all species. We are currently studying the importance of a second metal-binding motif, often called the NSE (or DTE) motif. The ultimate goal of these studies on this and other sesquiterpene cyclases is to be able to predict the products of a given sesquiterpene cyclases and to design novel sesquiterpenes that will form novel sesquiterpenes with various biological and commercial applications.