Chemoenzymatic studies of aminoglycoside-resistance enzymes towards new drugs

描述（由申请人提供）：氨基糖苷类抗生素是用于治疗严重细菌感染的广谱抗生素，包括致命的结核病和伴随的艾滋病、囊性纤维化和癌症。对这些药物产生耐药性的病原体的出现是对公共卫生的重大威胁，并强调了对新的抗菌剂的需求。在目的1中，我们提出利用氨基糖苷乙酰转移酶（AAC）家族的氨基糖苷修饰酶结合新开发的无6 ′-N-酰化保护基的化学方法（i）来产生新的和更有效的N-酰化氨基糖苷抗生素的体外文库，和（ii）开发氨基糖苷类探针，其将用作鉴定这些抗生素的新的治疗性蛋白质靶点/途径的诱饵。我们的化学酶和化学策略为以下问题提供了有效的解决方案：（i）目前还没有用于产生N-酰化氨基糖苷的通用合成方法，以及（ii）没有有效的方法来化学修饰含有一系列化学相同胺的氨基糖苷上的特定胺基。一些现有的例子，只使用化学合成太苛刻的研究时间和成本，并仅限于非常具体的情况。在目标2中，我们提出了广泛耐药的M.广泛耐药结核病。我们希望这项工作能够（i）推进对包括M.结核病，和（ii）提供了一个潜在的解决方案，以克服大多数广泛耐药结核病的氨基糖苷类耐药问题。与公共卫生的相关性：我们希望这项工作将有助于开发新的抗生素，具有对抗现有和新出现的耐药细菌的潜力。

DESCRIPTION (provided by applicant): Aminoglycosides are broad-spectrum antibiotics used for treatment of serious bacterial infections, including the deadly tuberculosis and those accompanying AIDS, cystic fibrosis, and cancer. The emergence of pathogens resistant to these drugs represents a major threat to public health and underscores the need for new antimicrobial agents. In Aim 1, we propose to utilize aminoglycoside-modifying enzymes of the aminoglycoside acetyltransferase (AAC) family in conjunction with a newly developed 6'-N-acylation protecting group-free chemical methodology (i) to generate in vitro libraries of new and more potent N-acylated aminoglycoside antibiotics, and (ii) to develop aminoglycoside probes that will serve as baits for identification of novel therapeutic protein targets/pathways for these antibiotics. Our chemoenzymatic and chemical strategies offer an effective solution to the following problems: (i) there are no existing general synthetic methodologies for the creation of N-acylated aminoglycosides, and (ii) there are no efficient methods to chemically modify specific amine groups on an aminoglycoside that contains a series of chemically identical amines. A few existing examples that use solely chemical syntheses are too demanding on research time and cost and are limited to very specific cases. In Aim 2, we propose biochemical and structural studies of the mechanism of action and inhibition of a major determinant of aminoglycoside resistance in extensively drug-resistant strains of M. tuberculosis (XDR-TB). We expect this work to (i) advance the basic understanding of AG resistance of a variety of pathogenic bacteria, including M. tuberculosis, and (ii) provide a potential solution to overcome the aminoglycoside resistance problem in majority of XDR- TB. Relevance to public health: We expect that this work will contribute to the development of novel antibiotics with a potential to combat existing and newly emerging drug-resistant bacteria.