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

催化tRNA中碱基交换反应的tRNA修饰酶的功能和构象性质，将利用组合化学的概念，通过有计划地合成的化学探针来研究。这种酶家族的不同成员来自生命的三个王国，它们在不同的底物范围内工作。底物识别的差异是通过蛋白质的构象适应和配体结合中的水分子参与实现的。使用精心设计的特定抑制剂文库，通过组合合成可以访问，我们想要解决不同的构象状态，这些状态展示了与这些酶的功能角色密切相关的底物识别的惊人的多功能性。Shigellaflexneri的蛋白质已被鉴定为特定抗生素治疗的靶点，因此潜在的线索可能会为后续的药物开发计划服务。本研究方案采用化学合成、分子模拟、X射线结晶学、定点突变和分子动力学模拟相结合的方法，获得了特定的分子探针，这些分子探针可以解决这类酶成员之间的不同构象状态，完成它们的功能作用。它们将有助于理解酶的性质，特别是在适应性和底物专一性方面。

The functional and conformational properties of tRNA modifyingenzymes, catalyzing the exchange reaction of bases in tRNA,will be studied by chemical probes synthesized in awell-planned strategy using the concepts of combinatorialchemistry. Different members of this enzyme family originatingfrom the three kingdoms of life operate on deviating ranges ofsubstrates. The differences in substrate recognition areachieved by conformational adaptations of the proteins and theinvolvement of a water molecule in ligand binding. Usingwell-tailored libraries of specific inhibitors, accessiblethrough combinatorial synthesis, we want to address thedifferent conformational states that demonstrate a surprisingversatility of substrate recognition intimately related to thefunctional role of these enzymes. The protein from Shigellaflexneri has been characterized as a target for a specificantibiotics therapy, thus potential leads could possibly servefor a subsequent drug development program. The present researchproposal uses a combined approach of chemical synthesis,molecular modeling, X-ray crystallography, site-directedmutagenesis and molecular dynamics simulations to give accessto specific molecular probes which address differentconformational states among the members of this enzyme class,required to accomplish their functional role. They will help tounderstand the enzymatic properties, in particular with respectto adaptability and substrate specificity.