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一种广谱抗生素，用于治疗严重的细菌感染，包括致命的结核病及其伴随的艾滋病、囊性纤维化和癌症。对这些药物具有耐药性的病原体的出现对公共卫生构成了重大威胁，并强调需要开发新的抗微生物药物。在目标1中，我们建议利用氨基糖苷乙酰转移酶（AAC）家族的氨基糖苷修饰酶与新开发的6'- n -酰化保护无基化学方法(i)生成新的和更有效的n -酰化氨基糖苷类抗生素的体外文库，以及（ii）开发氨基糖苷类探针，作为鉴定这些抗生素的新治疗蛋白靶点/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)没有现有的通用合成方法来创建n -酰化氨基糖苷，（ii）没有有效的方法来化学修饰氨基糖苷上的特定胺基，这些氨基糖苷含有一系列化学相同的胺。现有的一些仅使用化学合成的例子对研究时间和成本的要求太高，而且仅限于非常具体的情况。在Aim 2中，我们提出了广泛耐药结核分枝杆菌（XDR-TB）氨基糖苷耐药的主要决定因素的作用机制和抑制的生化和结构研究。我们期望这项工作(i)促进对包括结核分枝杆菌在内的多种致病菌AG耐药的基本认识，（ii）为克服大多数XDR- TB氨基糖苷耐药问题提供潜在的解决方案。与公共卫生的相关性：我们期望这项工作将有助于开发具有对抗现有和新出现的耐药细菌潜力的新型抗生素。

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.