Methylation in Antibiotic Biosynthesis: Methylcobalamin-Radical SAM Enzymes

我已获得学士学位。2000年在塞尔维亚和黑山的贝尔格莱德大学获得化学学士学位，并获得博士学位。 2005年5月在伊利诺伊大学香槟分校获得有机化学博士学位。在毕业期间 研究中，我开发了一种新的方法来进行化学选择性的糖-肽连接。 David Y.Gin教授和Wilfred A.van der Donk教授的联合指导。目前，我是达蒙·鲁尼昂 癌症研究基金会克里斯托弗·沃尔什教授的实验室博士后研究员 哈佛医学院。HMS和沃尔什教授正在提供一个出色的研究环境和 都致力于博士后研究员的成功。 我的博士后研究重点是最近发现的一类非血红素铁的特征 (2)卤化酶，能够对非活性碳中心进行卤化。到目前为止，我们已经 巴巴酰胺体系中重组的卤代活性。在这项研究中，我们证明了三重 载体-蛋白质连接的L-亮氨酸底物上未活化甲基的氯化反应 在两个非血红素的串联作用下，产生了卤化酶BarB1和BarB2。我目前正在调查 用预稳态法研究未活化碳中心卤化的机理 催化过程中金属中心的状态动力学参数及EPR和穆斯堡尔谱研究。 拟议项目的目标是对甲钴胺自由基SAM酶进行机械描述。 在抗生素生物合成中进行sp2碳中心的甲基化。我们的目标是了解 自然界用来引导甲钴胺、铁硫簇和脱氧腺苷自由基的逻辑 在酶学中进行这种新颖的碳-碳键的形成。甲基化事件将在 氨基香豆素抗生素中5-甲基-2-吡咯-2-羧酸盐药效团的产生背景 生物合成，以及β-内酰胺类抗生素硫霉素生物合成中的羟乙基侧链。 更好地了解参与抗生素生物合成的酶可以导致新的 通过组合生物合成的抗生素变体。这一点尤其重要，因为 细菌对常用抗生素的耐药性发展。

I have obtained B. Sc. in chemistry from University of Belgrade, Serbia and Montenegro, in 2000, and Ph. D. in organic chemistry from University of Illinois at Urbana-Champaign in May 2005. During graduate studies, I have developed new methods for the chemoselective carbohydrate-peptide ligations under the joint guidance of Professors David Y. Gin and Wilfred A. van der Donk. Currently, I am a Damon Runyon Cancer Research Foundation postdoctoral fellow in the laboratory of Professor Christopher T. Walsh at Harvard Medical School. HMS and Professor Walsh are providing an outstanding research environment and are committed to the success of the postdoctoral fellows. My postdoctoral research is focused on the characterization of a recently discovered class of nonheme Fe (II) halogenases, capable of carrying out halogenation of unactivated carbon centers. Thus far, we have reconstituted halogenation activity in the barbamide system. In this study, we demonstrated that the triple chlorination of the unactivated methyl group of the carrier-protein tethered L-leucine substrate is mediated by the tandem action of two nonheme Fell halogenases, BarB1 and BarB2. I am currently investigating mechanistic aspects of halogenation of unactivated carbon centers through the investigation of pre-steady state kinetic parameters and EPR and Mossbauer investigation of metal center during the catalysis. The objective of the proposed project is mechanistic description of methylcobalamin-radical SAM enzymes that carry out methylations of sp2 carbon centers in antibiotic biosynthesis. Our goal is to understand the logic that nature uses to channel methylcobalamin, iron-sulfur clusters and deoxyadenosyl radicals to perform this novel carbon-carbon bond formation in enzymology. The methylation event will be studied in the context of generation of the 5-methylpyrrole-2-carboxylate pharmacophore in aminocoumarin antibiotic biosynthesis, and hydroxyethyl side chain in the biosynthesis of beta lactam antibiotic thienamycin. Better understanding of enzymes involved in the antibiotic biosynthesis can lead to the development of new antibiotic variants through combinatorial biosynthesis. This is especially important because of the development of bacterial resistance to commonly used antibiotics.