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

血红素、叶绿素、辅酶F430和类胡萝卜素等辅因子是由8个5-氨基酮戊酸酯分子构成的，它构成了所有四吡咯的基石。在植物和细菌中，这种化合物是由负合作关键酶谷氨酸-1-半醛氨基变位酶(GSAM)合成的。该研究计划的主要目标是详细了解GSAM的结构-功能关系和催化机理。本研究的目的是获得该酶的机制和化学信息，目的是(1)研究C5途径和血敏途径之间的进化关系；(2)阐明催化周转过程中亚单位间的信号转导；(3)设计和分析针对GSAM的特异性抑制剂。由于这种酶在动物中不存在对应的酶，因此它是安全、选择性除草剂和此类化合物的合理设计的有希望的靶标。在Stetefeld实验室，将执行一种综合方法。这些研究涉及结构(X射线结晶学和溶液核磁共振)、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相结合。这些实验将得到分子动力学模拟的补充。这项研究不仅将加深我们对酶催化过程中变构通讯的认识，而且将为基于结构的高选择性除草剂的药物设计提供新的见解。了解进化选择过程中酶混杂的复杂机制将提供具有重大生物技术意义的蛋白质化学的进一步信息。这些结果将有助于在全球视角下设计特定和靶向的抑制剂的基本知识。

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.