Making New Enzymes from Old

9814455本研究项目的目标是开发和探索一种实验方法的应用，该方法将允许系统地改变现有酶的性质。 通过一种被称为位点特异性调节的方法，研究人员提出了一种结合了阿托伐他汀定向诱变（绝对位点特异性）和化学修饰（引入广泛的结构类似物）的方法来改变酶中选定的氨基酸。 将制备一系列氨基酸类似物试剂，以将该方法应用于几种特定的酶。 碳酸酐酶的动力学将通过锌配体和质子穿梭基团的身份的修饰而改变。 苹果酸脱氢酶的底物特异性和立体特异性将通过选择性地将非天然氨基酸引入活性位点来调节。 最后，这些研究人员计划利用从碳酸酐酶的金属结合位点的改变中获得的知识来设计和引入新的金属离子结合位点和相应的新催化活性到苹果酸脱氢酶中。酶，自然界的催化剂，控制和加速生命系统中的所有化学反应。 研究人员还没有成功地设计出全新的催化剂，可以模仿酶的显着效率。 这些研究人员将探索一种有望扩大现有酶范围的方法，从而使它们能够催化新的反应。 设计可以特别调整以加速靶向化学反应的改变的酶可以具有广泛的新商业和基础应用。

9814455The goal of this research project is to develop and explore the applications of an experimental approach that will allow a systematic alteration of the properties of existing enzymes. Through a method called site specific modulation the investigators propose the alteration of selected amino acids in an enzyme by an approach that combines the strengths of oligonucleotide-directed mutagenesis (absolute site specificity) and chemical modification (introduction of a wide range of structural analogs). A range of amino acid analog reagents will be prepared to apply this method to several specific enzymes. The kinetics of carbonic anhydrase will be altered by modifications in both the zinc ligands and in the identity of the proton shuttle group. The substrate specificity and stereospecificity of malate dehydrogenase will be tuned by the selective introduction of unnatural amino acids into the active site. Finally, these investigators plan to use the knowledge that has been gained from alterations in the metal binding site of carbonic anhydrase to design and introduce a new metal ion binding site and commensurate new catalytic activity into malate dehydrogenase.Enzymes, natures' catalysts, control and accelerate all chemical reactions in living systems. Researchers have not yet succeeded in designing completely new catalysts that can mimic the remarkable efficiency of enzymes. These investigators will be exploring a method that has the promise of expanding the scope of existing enzymes, thus allowing them to catalyze new reactions. Designing altered enzymes that can specifically be tuned to accelerate targeted chemical reactions can have broad new commercial and basic applications.