AMINOGLYCOSIDE/RNA INTERACTIONS AND CORNEAL INFECTIONS

RNA分子能够形成精确的三维结构，可以作为有机小分子的结合部位。理解管理RNA/小分子识别过程规则的规则将允许我们实现针对特定RNA结构的拮抗剂从头设计的长期目标，就像抑制剂是为蛋白质基酶和受体设计的一样。为抑制RNA分子而设计的特定抑制剂可能会在眼科以及一般的医学领域产生巨大的兴趣，例如，在小分子的设计中，可以专门干扰可能导致视网膜退化的突变蛋白质的表达，以及在小分子的设计中，可以对抗来自感染性疾病产生生物的RNA分子。本提案描述了了解特定RNA分子识别某些类型的自然产生的RNA拮抗剂氨基糖苷类的规则的方法。通过柱法选择随机的RNA分子与定义的含有高亲和力和特异性的抗生素的氨基糖苷类结合。发展了新的定量荧光方法来确定抗生素与选定的RNA适配子结合的亲和力和化学计量比。发展了新的化学方法来揭示定义特定抗生素结合位点的适体区域。计划对高亲和力结合适体进行高场核磁共振结构研究。将确定特定RNA适配子中识别特定氨基糖苷类的基序，并将其用作未来针对自然产生的RNA分子的特定拮抗剂设计的指南。在这方面，两个特别感兴趣的生物存在的RNA分子是原核16S rRNA解码区和HIV-RRE转录激活区。通过对氨基糖苷与解码区和RRE区结合的定量构效关系研究，设计了含有L，3(2)-羟胺基团的新型氨基糖苷类多样性文库。针对RNA的解码区和RRE区的特异性拮抗剂将被制备并进行定量研究。这些拮抗剂有望成为设计用于治疗角膜感染的药物的起点。总体而言，这里描述的研究将作为设计特定RNA拮抗剂的一般程序的基础。

RNA molecules are able to form precise three-dimensional structures which can be binding-sites for small organic molecules. An understanding of the rules that govern RNA/small molecule recognition processes rules would allow for an approach to our long-term goal of the de novo design of antagonists directed at particular RNA structures, in much the same way that inhibitors are designed for protein-based enzymes and receptors. Specific inhibitors designed to inhibit RNA molecules could be of enormous interest in ophthalmology and generally in medicine, in the design, for example, of small-molecules that can specifically interfere with the expression of mutant proteins that can lead to retinal degeneration, and in the design of small molecules that can antagonize RNA molecules from infectious disease producing organisms. This proposal describes approaches to gaining an understanding of the rules by which certain classes of naturally occurring RNA antagonists, the aminoglycosides, are recognized by specific RNA molecules. Random RNA molecules are selected by column methods to bind to defined aminoglycoside containing antibiotics with high affinity and specificity. New quantitative fluorescence methods are developed to determine the affinities and stoichiometries of antibiotic binding to the selected RNA aptamers. Novel chemical approaches are developed to reveal the regions of the aptamers which define the binding-sites for the specific antibiotic. High field NMR structural studies on the high affinity binding aptamers are planned. Those motifs in the specific RNA aptamers which recognize particular aminoglycosides will be determined and used as a guide for the future design of specific antagonists directed against naturally occurring RNA molecules. Two biologically occurring RNA molecules of particular interest in this context are the procaryotic 16S rRNA decoding region and the HIV-RRE transcriptional activator region. Quantitative structure-activity studies on aminoglycoside binding to the decoding and RRE regions leads to the design of novel aminoglycosidemimetic diversity libraries containing l,3(2)-hydroxylamine moieties. Specific antagonists directed against the decoding and RRE regions of RNA will be prepared and studies quantitatively. These antagonists are expected to be starting points for the design of drugs useful in the treatment of corneal infections. Overall, the studies described herein will serve as the basis for a general program on the design of specific RNA antagonists.