Development of Artificial Agonists for a Bacterial Riboswitch

细菌核糖开关人工激动剂的开发

• 批准号: 7247818
• 负责人: JULIANE K STRAUSS-SOUKUP
• 金额: $ 21.53万
• 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 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7247818
• 关键词: Affect; Agonist; Amines; Antibiotic Resistance; Antibiotics; Bacteria; Bacterial Infections; Binding; Biochemical; Biological Assay; Catalysis; Catalytic RNA; Cell Wall; Class; Complex; Development; Elements; Feedback; Functional RNA; Gene Expression; Gene Expression Alteration; Genes; Genetic; Gram-Positive Bacteria; Grant; Growth; Hydrogen Bonding; In Vitro; Ions; Kinetics; Ligands; Maps; Measurement; Messenger RNA; Metabolic; Metabolic Pathway; Metabolism; Metals; Play; Process; RNA; Range; Rate; Regulation; Reporter; Resistance; Role; Structure; Today; Work; analog; antimicrobial drug; chemical group; design; fighting; functional group; glucosamine 6-phosphate; in vivo; inorganic phosphate; insight; interest; novel; novel strategies; nucleobase; nucleotide analog; pathogen; 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 limited group of antibiotics, currently in use, 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 one of their most essential processes, metabolism. The recent discovery of RNA structural elements, termed riboswitches, that bind cellular metabolites and control expression of essential metabolic genes provides a unique and distinct target for development of artificial agonists to fight bacterial infections. Riboswitches are found in non-coding regions of messenger RNAs, and gene expression is modulated when metabolite binds directly to the RNA. Many riboswitches repress expression of nearby 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 inactivity of the mRNA. The amine functionality of GlcN6P seems to be directly involved in RNA catalysis, whereas the phosphate may play a role in recognition of the ligand by the RNA. In order to develop effective artificial agonists/antibiotics that target the glmS riboswitch, an understanding of the structural and functional details of the riboswitch-metabolite complex is essential. The aims of this grant focus on (1) investigating the structural and catalytic roles of metal ions in the glmS riboswitch, (2) deciphering ligand recognition by the glmS riboswitch, and (3) designing non-natural agonists with the ability to stimulate glmS riboswitch self-cleavage and control gene expression. Using Nucleotide Analog Interference Mapping and Suppression (NAIM and NAIS, respectively) some of the long range contacts between the glmS riboswitch, its ligand, and metal ions will be determined. Using NAIM, the biochemical contribution of a single chemical group within the glmS riboswitch will be defined using nucleotide analogs that modify the atom(s) of interest. Using NAIS, specific tertiary hydrogen bonding partners within or involving the glmS RNA structure will be determined. Structure-function studies of riboswitches will enable rational design of non-natural metabolite-like compounds that might function as agonists/antibiotics to halt bacterial growth through alteration of gene expression. 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 studies of riboswitches will enable rational design of non-natural agonists that ultimately could function as antibiotics.

描述（由申请人提供）：抗生素耐药性的出现要求采用新的方法来有效对抗许多医学相关的细菌感染。目前使用的抗生素种类有限，需要用新颖、严格且安全的治疗方法来替代，以对抗当今进化的细菌。消灭细菌的一种方法是针对细菌最重要的过程之一——新陈代谢。最近发现的 RNA 结构元件（称为核糖开关）可以结合细胞代谢物并控制必需代谢基因的表达，为开发抗细菌感染的人工激动剂提供了独特且独特的靶点。核糖开关存在于信使 RNA 的非编码区，当代谢物直接与 RNA 结合时，基因表达就会受到调节。许多核糖开关抑制附近参与代谢物合成的基因的表达，提供有效的遗传控制反馈机制。一种特殊的核糖开关（glmS 核糖开关）与 6-磷酸葡萄糖胺 (GlcN6P)（革兰氏阳性细菌细胞壁的组成部分）结合，并经历自我裂解，导致 mRNA 失活。 GlcN6P 的胺官能团似乎直接参与 RNA 催化，而磷酸盐可能在 RNA 识别配体中发挥作用。为了开发针对 glmS 核糖开关的有效人工激动剂/抗生素，了解核糖开关-代谢物复合物的结构和功能细节至关重要。该资助的目的集中在（1）研究金属离子在glmS核糖开关中的结构和催化作用，（2）破译glmS核糖开关的配体识别，以及（3）设计具有刺激glmS能力的非天然激动剂核糖开关自我切割并控制基因表达。使用核苷酸模拟干扰图谱和抑制（分别为 NAIM 和 NAIS），将确定 glmS 核糖开关、其配体和金属离子之间的一些长距离接触。使用 NAIM，glmS 核糖开关内单个化学基团的生化贡献将使用修饰感兴趣原子的核苷酸类似物来定义。使用 NAIS，将确定 glmS RNA 结构内或涉及 glmS RNA 结构的特定三级氢键伙伴。核糖开关的结构功能研究将使非天然代谢物类化合物的合理设计成为可能，这些化合物可能充当激动剂/抗生素，通过改变基因表达来阻止细菌生长。由于缺乏有效的抗生素而导致的细菌感染威胁已成为首要问题，因为这些病原体对几乎所有可供公众使用的抗生素都产生了抗药性。非常需要针对不同但特定且重要的代谢途径的新型抗微生物剂，例如利用核糖开关控制基因表达的途径。核糖开关的结构功能研究将使非天然激动剂的合理设计成为可能，最终可以起到抗生素的作用。