Targeting a novel regulatory RNA with novel antibiotics

描述(申请人提供)：对抗生素的抗药性正在成为对公众健康的主要威胁，我们面临着现有抗生素可能不再足以治疗传染病的风险。迫切需要获得新的抗菌化合物，并开发生产此类化合物的新方法。本研究的目的是开发新型抗菌剂，与T盒RNA的抗终止子元件特异性结合，抑制抗终止性，从而抑制细菌细胞生长。我们已经在细菌RNA中发现了一种新的调控元件，即T盒系统抗终止子，它是抗菌药物开发的理想靶点。这种RNA元件广泛分布于革兰氏阳性菌中，是表达必需的氨基酰-tRNA合成酶(AARS)基因所必需的。抑制T盒功能会抑制细菌细胞的生长，从而证实该成分是抗菌药物的靶点。我们的假设是，所提出的新的恶唑烷酮类化合物和相关化合物可以开发成新的抗菌剂，并且T盒抗终止系统为抗菌作用提供了一个独特的靶点，减少了产生耐药性的可能性。我们的初步结果表明：a)这类新的恶唑烷酮类化合物的先导成员以低微摩尔与纳摩尔的亲和力和良好的选择性结合抗终止子RNA，具有独特的RNA结构；b)恶唑烷酮铅与与抗终止子RNA结合的tRNA竞争；c)恶唑烷酮铅对革兰氏阳性细菌具有抗菌活性；以及d)一种先导化合物在体外抑制转录抗终止。具体目标是：1)合成和设计新的恶唑烷酮类化合物及相关化合物；2)测定抗终止子模型RNA的亲和力，测定新化合物的抗菌活性；3)确定具有抗菌活性的化合物的作用方式。AIMS 2和AIMS 3确定的构效关系(SAR)将用于通过分子建模、核磁共振溶液结构研究和定量SAR分析来指导化合物设计的反复几轮化合物改进。

DESCRIPTION (provided by applicant): Resistance to antibiotics is becoming a major threat to public health and we are facing a risk that available antibiotics may no longer be adequate for treatment of infectious diseases. There is a compelling need for obtaining new antibacterial compounds, and for developing new methods for the production of such compounds. The goal of this study is to develop novel antibacterial agents that specifically bind to the antiterminator element of T box RNAs and inhibit antitermination, thereby inhibiting bacterial cell growth. We have identified a novel regulatory element in bacterial RNA, the T box system antiterminator that is an ideal target for antibacterial drug discovery. This RNA element is widely distributed in Gram-positive bacteria, where it is required for expression of essential aminoacyl-tRNA synthetase (aaRS) genes. Inhibition of T box function results in inhibition of bacterial cell growth, validating this element as a target for antimicrobial agents. Our hypothesis is that the proposed new classes of oxazolidinones and related compounds can be developed into novel antibacterial agents and that the T box antitermination system provides a unique target for antibacterial action with decreased probability of development of resistance. Our preliminary results demonstrate that: a) lead members of this new class of oxazolidinones bind antiterminator RNA with low micromolar to nanomolar affinities and good selectivity for a unique RNA structure; b) lead oxazolidinones compete with tRNA binding to antiterminator RNA; c) lead oxazolidinones have antibacterial activity against Gram-positive bacteria; and d) a lead compound inhibits transcription antitermination in vitro. Specific Aims are: 1) Synthesize and design new classes of oxazolidinones and related compounds; 2) Determine affinity for antiterminator model RNA and determine antibacterial activity of new compounds: and 3) Confirm the mode of action of compounds with antibacterial activity. The structure activity relationships (SAR) determined from Aims 2 and 3 will be used in iterative rounds of compound improvement utilizing molecular modeling, NMR solution structure studies and quantitative SAR analysis to guide the design of compounds.