Specific Inhibition of a Conformationally Flexible t-RNA Modifying Enzyme by Ligands Synthesized by Combinatorial Chemistry

tRNA修饰酶的功能和构象特性，催化tRNA中碱基的交换反应，将通过使用组合化学的概念在精心策划的策略中合成的化学探针来研究。这个酶家族的不同成员起源于三个生命王国，对不同范围的底物起作用。底物识别的差异是通过蛋白质的构象适应和水分子参与配体结合来实现的。使用量身定制的特定抑制剂库，通过组合合成，我们希望解决不同的构象状态，表现出令人惊讶的多功能性的底物识别密切相关的功能作用，这些酶。来自福氏志贺菌的蛋白质已被表征为特定抗生素治疗的靶点，因此潜在的线索可能用于随后的药物开发计划。本研究建议使用化学合成，分子建模，X射线晶体学，定点诱变和分子动力学模拟的组合方法，以获得特定的分子探针，这些探针可以解决该类酶的成员之间的不同构象状态，需要完成其功能作用。它们将有助于理解酶的性质，特别是关于适应性和底物特异性。

The functional and conformational properties of tRNA modifying enzymes, catalyzing the exchange reaction of bases in tRNA, will be studied by chemical probes synthesized in a well-planned strategy using the concepts of combinatorial chemistry. Different members of this enzyme family originating from the three kingdoms of life operate on deviating ranges of substrates. The differences in substrate recognition are achieved by conformational adaptations of the proteins and the involvement of a water molecule in ligand binding. Using well-tailored libraries of specific inhibitors, accessible through combinatorial synthesis, we want to address the different conformational states that demonstrate a surprising versatility of substrate recognition intimately related to the functional role of these enzymes. The protein from Shigella flexneri has been characterized as a target for a specific antibiotics therapy, thus potential leads could possibly serve for a subsequent drug development program. The present research proposal uses a combined approach of chemical synthesis, molecular modeling, X-ray crystallography, site-directed mutagenesis and molecular dynamics simulations to give access to specific molecular probes which address different conformational states among the members of this enzyme class, required to accomplish their functional role. They will help to understand the enzymatic properties, in particular with respect to adaptability and substrate specificity.