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

点击翻译按钮获取中文摘要

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.