Structure-function studies on glutamate-1-semialdehyde aminomutase (GSAM)- A key enzyme in chlorophyll biosynthesis

辅酶如血红素、叶绿素、辅酶F430和类胡萝卜素都是由8个5-氨基乙酰酸分子构成的，而5-氨基乙酰酸分子是所有四环醇的基本成分。在植物和细菌中，该化合物是由负合作关键酶谷氨酸-1-半醛氨基交换酶（GSAM）合成的。本研究计划的主要目的是详细了解GSAM的结构-功能关系和催化机理。目的是获得该酶的机制和化学信息，目的是：(1)研究C5和shemin通路之间的进化关系，(2)阐明催化转换过程中亚基间信号传导，(3)设计和分析针对GSAM的特异性抑制剂。由于该酶在动物体内不存在对应物，因此它是安全、选择性除草剂和合理设计此类化合物的一个有希望的目标。在Stetefeld实验室，将执行一种综合方法。这些研究包括结构（x射线晶体学和溶液核磁共振）、光谱（UV-VIS和Foerster共振电子转移）技术以及功能分析和动力学研究。这些实验将辅以分子动力学模拟。该研究不仅将增强我们对酶催化过程中变构沟通的认识，而且将为基于结构的高选择性除草剂药物设计提供见解。了解进化选择过程中酶乱交的复杂机制将为进一步了解蛋白质化学提供重要的生物技术相关信息。这些结果将有助于在设计特异性和靶向抑制剂的全球视角下提供基础知识。

Cofactors like heme, chlorophyll, coenzyme F430, and carotinoids are constructed from eight molecules of 5-aminolevulinate, which forms the building block for all tetrapyrrols. In plants and bacteria, this compound is synthesized by the negative cooperative key enzyme glutamate-1-semialdehyde aminomutase (GSAM). The primary goal of the proposed research program is to understand in detail the structure-function relationship and catalytic mechanism of GSAM. The purpose is to obtain mechanistic and chemical information about this enzyme with the goal (i) to investigate the evolutionary relationship between the C5 -and the Shemin-pathways, (ii) to shed light into the inter-subunit signaling during catalytic turnover and (iii) to design and analyze specific inhibitors against GSAM. Because no counterpart of this enzyme exists in animals, it is a promising target for safe, selective herbicides and the rational design of such compounds. In the Stetefeld laboratory, an integrated approach will be performed. These studies involve a combination of structural (X-ray crystallography and solution NMR), spectroscopical (UV-VIS and Foerster Resonance Electron Transfer) techniques together with functional assays and kinetic studies. These experiments will be complemented by Molecular Dynamic simulations. Not only will the research enhance our knowledge of the allosteric communication during enzyme catalysis, but insights will be gained into structure-based drug design of highly selective herbicides. Understanding the complex mechanisms of enzyme promiscuity during evolutionary selection will provide further information about protein chemistry with great biotechnological relevance. The results will contribute to basic knowledge under the global perspective of designing specific and targeted inhibitors.