TRICHODIENE SYNTHASE

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 Trichodiene synthase（TS）是一种Mg（II）依赖性倍半萜环化酶。倍半萜环化酶以精确的几何和立体化学精度催化通用无环底物法呢基二磷酸转化为众多环状和手性倍半萜烃或醇中的一种。这些倍半萜烯是几种分子的前体，这些分子在我们的日常生活中对我们非常重要，如抗生素，烹饪添加剂，香水等。TS进化到只形成β-二烯。然而，在酶的活性位点中的保守位点特异性突变不仅影响酶的活性，而且使酶偏离轨道，使其产生比产物或底物更类似于中间体的额外产物。因此，对这些产物的研究以及某种突变如何产生某些异常产物的研究有助于阐明酶的作用机制。我们正在通过研究突变TS酶及其与各种配体的复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位点的功能，该活性位点不形成完全定制的模板以专门形成β-二烯。配体结合的活性位点的体积通常在突变体中比在野生型酶中大得多。我们已经研究了一个富含柠檬酸的基序，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，通常称为NSE（或DTE）基序。对这种和其它倍半萜环化酶的这些研究的最终目标是能够预测给定的倍半萜环化酶的产物并设计将形成具有各种生物学和商业应用的新型倍半萜的新型倍半萜。

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.