Enzymatic Fluoroalkylation using Te-Adenosyl-Telluromethionine Analogs and Late-Stage Diversification of Natural Products Exhibiting Antibacterial Behavior

项目摘要 甲基是天然产物中的一种重要的结构修饰，通常是 天然产物作为抗菌和/或抗肿瘤药物的有效性。在自然界中，这些甲基是 区域选择性中最常附加S-腺苷甲硫氨酸依赖的甲基转移酶 和立体选择的方式。这项提案的重点是转移氟甲基和其他含氟 将烷基转化为天然产物，因为氟原子已被证明具有增强药理作用 很多药物的作用。事实上，大约20%-30%的药物至少含有一个氟原子。战略以实现 因此，将氟引入生物分子是有机和药物化学的前沿。在这 建议合成具有生物相关性的新型氟甲基和二氟甲基供体 描述。事实上，我们证明了这些含氟的SAM类似物，Te-腺苷-(氟甲基)- 硫代蛋氨酸(FMeTeSAM)和Te-adenosyl-(difluoromethyl)-telluromethionine(F2MeTeSAM) 通过依赖SAM的MTS将氟烷基转移到目标底物上，包括儿茶酚-O- 甲基转移酶催化的二羟基苯甲酸O-氟甲基化和O-二氟甲基化 去甲肾上腺素；烟酰胺N-甲基转移酶催化的烟酰胺N-氟甲基化 香豆素催化的C-氟甲基化；6-巯基嘌呤甲基转移酶催化的S- 6-硫代嘌呤的二氟甲基化反应。理想情况下，这种能力将被用来修饰含有甲基的 具有临床价值的天然产物(如新诺贝菌素和草碱)，以一种简便的方式 在其生物合成途径的后期阶段，并评估其药理作用是否得到改善。 其他目标将集中在酶法合成β-氟甲基氨基酸上，这些氨基酸在许多 重要的抗生素，以及在完全未活化的碳中添加氟甲基 通过激进的机制实现中心。

Project Summary Methyl groups are an important structural modification in natural products and are often essential for the effectiveness of natural products as antibacterial and/or antitumor agents. In nature, these methyl groups are most often appended by S-adenosylmethionine (SAM)-dependent methyltransferases (MTs) in a regioselective and stereoselective manner. This proposal focuses on transferring fluoromethyl and other fluorine-containing alkyl groups to natural products, because fluorine atoms have been shown to enhance the pharmacological effects of many drugs. In fact, about 20-30% of all drugs contain at least one fluorine atom. Strategies for introducing fluorine into biomolecules are therefore at the forefront of organic and medicinal chemistry. In this proposal, the the synthesis of novel fluoromethyl and difluoromethyl donors that have biological relevance is described. Indeed, we show that these fluorine-containing analogs of SAM, Te-adenosyl-(fluoromethyl)- telluromethionine (FMeTeSAM) and Te-adenosyl-(difluoromethyl)-telluromethionine (F2MeTeSAM) are acted upon by SAM-dependent MTs to transfer fluoroalkyl groups to target substrates, including catechol-O- methyltransferase-catalyzed O-fluoromethylation on dihydroxybenzoic acid and O-difluoromethylation on norepinephrine; nicotinamide N-methyltransferase-catalyzed N-fluoromethylation on nicotinamide; NovO- catalyzed C-fluoromethylation on coumarin; and 6-mercaptopurine methyltransferase-catalyzed S- difluoromethylation on 6-mercaptopurine. Ideally, this ability will be leveraged to modify methyl-containing natural products of clinical value (e.g. novobiocin and oxaline) with fluoromethyl groups in a facile manner at a late stage in their biosynthetic pathways, and to assess whether their pharmacological effects are improved. Other aims will focus on the enzymatic synthesis of β-fluoromethyl amino acids, which are found in a number of important antibiotics, as well as the addition of fluoromethyl groups to completely unactivated carbon centers via radical mechanisms.