Antibiotic Properties of Artificial Agonists for a Bacterial Riboswitch

细菌核糖开关人工激动剂的抗生素特性

• 批准号: 7980700
• 负责人: JULIANE K STRAUSS-SOUKUP
• 金额: $ 43.58万
• 依托单位: CREIGHTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7980700
• 关键词: Acids; Active Sites; Affect; Agonist; Amines; Ampicillin; Antibiotic Resistance; Antibiotics; Bacteria; Bacterial Infections; Binding; Biological Assay; Catalysis; Catalytic RNA; Cell Wall; Chemicals; Cleaved cell; Collaborations; Complex; Development; Elements; Equipment and supply inventories; Feedback; Functional RNA; Gene Expression; Genes; Genetic; Goals; Gram-Positive Bacteria; Grant; Growth; Human; Humulus; In Vitro; Ions; Isotopes; Kinetics; Laboratories; Ligands; Messenger RNA; Metabolic; Metabolic Pathway; Metals; Methods; Organic Synthesis; Property; Protons; RNA; Reaction; Regulation; Reporter Genes; Resistance; Solvents; Structure; Testing; analog; antimicrobial drug; base; combat; design; fighting; glucosamine 6-phosphate; in vivo; inorganic phosphate; insight; novel; novel strategies; pathogen; public health relevance; research study

DESCRIPTION (provided by applicant): The emergence of antibiotic resistance has required that new approaches be applied in order to effectively fight a host of medically relevant bacterial infections. The currently used, imprecise antibiotics, need to be replaced with novel, rigorous, and safe treatments in order to combat the evolved bacterium of today. One way to destroy bacteria is to target their most essential, metabolic pathways. Riboswitches are RNA structural elements that bind cellular metabolites and control expression of essential metabolic genes providing a unique and distinct set of targets for development of artificial agonists to fight bacterial infections. Riboswitches are found in non-coding regions of mRNA molecules, and gene expression is modulated when metabolite binds directly to the RNA. Many riboswitches, once liganded, repress expression of associated or adjacent genes involved in the synthesis of the metabolite, providing an efficient feedback mechanism of genetic control. One particular riboswitch (the glmS riboswitch) binds to glucosamine-6-phosphate (GlcN6P), a building block of the cell wall in Gram-positive bacteria, and undergoes self-cleavage resulting in inactivation of the mRNA. We have shown that the ligand amine and phosphate functionalities are essential for binding of the metabolite to the riboswitch RNA and for catalysis by the catalytic RNA (ribozyme). These requirements for binding and catalysis of the GlcN6P-dependent riboswitch/ribozyme have been shared with our collaborator, Dr. David Berkowitz, to aid in design and organic syntheses of novel ligand analogs. We will test these analogs for their ability to induce glmS self-cleavage and inhibit bacterial growth. Already one ligand analog shows great promise in glmS self-cleavage assays. We also propose to continue our studies of the glmS self-cleavage reaction mechanism as further insight to acid-base catalysis may affect development of glmS ribozyme agonists that satisfy added chemical requirements for binding and activity. The aims of this renewal grant are focused on (1) ligand analog synthesis and characterization of glmS self-cleavage, (2) the structure, function and antibiotic properties of artificial agonists in regards to glmS riboswitch regulation of reporter gene expression and inhibition of bacterial growth, and (3) mechanistic studies of glmS-supported acid-base catalysis through coordinated proton transfer. Information gained from kinetic studies will further inform our continued design of ligand analogs that support glmS riboswitch/ribozyme catalysis and that act as novel antimicrobial agents against some of the hardest to treat human pathogens. PUBLIC HEALTH RELEVANCE: The threat of bacterial infections due to lack of effective antibiotics has come to the forefront as these pathogens become resistant to almost every antibiotic available to the public. The need is great for new classes of anti-microbial agents that target different, but specific and essential, metabolic pathways, such as those which utilize riboswitches to control gene expression. Structure-function and mechanistic studies of riboswitches have enabled detailed analyses of ligand recognition by RNA as well as rational design of non-natural agonists that ultimately could function as antibiotics.

描述(申请人提供)：抗生素耐药性的出现要求应用新的方法，以便有效地对抗一系列与医学相关的细菌感染。目前使用的不精确的抗生素需要用新的、严格的和安全的治疗方法来取代，以对抗当今进化的细菌。消灭细菌的一种方法是瞄准它们最基本的代谢途径。核糖开关是结合细胞代谢物和控制必需代谢基因表达的RNA结构元件，为开发抗细菌感染的人工激动剂提供了一套独特和独特的靶点。核糖开关位于mRNA分子的非编码区，当代谢物直接与RNA结合时，基因表达受到调控。许多核糖开关一旦连接，就会抑制与代谢物合成有关的相关或相邻基因的表达，从而提供一种有效的遗传控制反馈机制。一种特定的核糖开关(GLMS核糖开关)与氨基葡萄糖-6-磷酸(GlcN6P)结合，并经历自我切割，导致mRNA失活。我们已经证明了配体、胺和磷酸的官能团对于代谢物与核糖开关RNA的结合以及催化RNA(核酶)的催化是必不可少的。这些对依赖GlcN6P的核糖开关/核酶的结合和催化的要求已经与我们的合作者David Berkowitz博士分享，以帮助设计和有机合成新的配体类似物。我们将测试这些类似物诱导GLMS自我切割和抑制细菌生长的能力。已经有一种配体类似物在GLMS自切割分析中显示出巨大的前景。我们还建议继续我们对GLMS自切割反应机理的研究，因为对酸碱催化的进一步了解可能会影响GLMS核酶激动剂的开发，这些激动剂满足结合和活性的额外化学要求。这一续期拨款的目的集中在(1)GLMS自切割的配体模拟合成和表征，(2)关于GLMS核糖开关调节报告基因表达和抑制细菌生长的人工激动剂的结构、功能和抗菌特性，以及(3)通过配位质子转移支持GLMS支持的酸碱催化的机理研究。从动力学研究中获得的信息将进一步为我们继续设计配体类似物提供依据，这些配体类似物支持GLMS核糖开关/核酶催化，并作为新型抗菌剂来对抗一些最难治疗的人类病原体。 与公共卫生相关：由于缺乏有效的抗生素，细菌感染的威胁已成为当务之急，因为这些病原体对公众提供的几乎所有抗生素都产生了抗药性。对针对不同但特定和必要的代谢途径的新型抗微生物制剂的需求很大，例如那些利用核糖开关控制基因表达的途径。核糖开关的结构-功能和机制研究使人们能够详细分析RNA对配体的识别，以及合理设计最终可用作抗生素的非天然激动剂。