Targeting a novel regulatory RNA with novel antibiotics

描述（由申请人提供）：对抗生素的耐药性正在成为对公共卫生的主要威胁，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，并开发生产这种化合物的新方法。本研究的目的是开发新的抗菌剂，特异性地结合到T盒RNA的抗终止子元件并抑制抗终止，从而抑制细菌细胞生长。我们已经确定了一种新的细菌RNA的调节元件，T盒系统antiterminator，是一个理想的目标抗菌药物的发现。该RNA元件广泛分布于革兰氏阳性菌中，其中必需氨酰-tRNA合成酶（阿尔斯）基因的表达需要该RNA元件。T盒功能的抑制导致细菌细胞生长的抑制，验证了该元件作为抗微生物剂的靶标。我们的假设是，提出的新类别的恶唑烷酮和相关化合物可以开发成新的抗菌剂，T盒抗终止系统提供了一个独特的目标，抗菌作用与耐药性的发展概率降低。我们的初步结果表明：a）这类新的恶唑烷酮类化合物的主要成员结合抗终止子RNA，具有低微摩尔至纳摩尔的亲和力和对独特RNA结构的良好选择性; B）主要恶唑烷酮类化合物与tRNA竞争结合抗终止子RNA; c）主要恶唑烷酮类化合物对革兰氏阳性菌具有抗菌活性; d）主要化合物在体外抑制转录抗终止。具体目标是：1）合成和设计新型恶唑烷酮及相关化合物; 2）测定抗终止子模型RNA的亲和力并测定新化合物的抗菌活性：3）确认具有抗菌活性的化合物的作用方式。根据目标2和3确定的构效关系（SAR）将用于利用分子建模、NMR溶液结构研究和定量SAR分析的化合物改进迭代轮次中，以指导化合物的设计。

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.