This project will result in the development of potent new inhibitors for a novel enzyme target that is specific to the metabolism of fungi and yeast: the group II self-splicing intron. This structurally complex and highly conserved ribozyme plays a key role in RNA processing and metabolic function of lower eukaryotes, but it is not present in humans and other vertebrates. Group II intron inhibitors therefore present a specific and potentially powerful new approach for combating pathogenic fungi and yeast, which represent a major public health problem for which therapeutic strategies are increasingly limited. Indeed, fungal infections are a major source of mortality and morbidity among AIDS patients, neonatal patients, and as these pathogens diversify, even among the noncompromised general population. Extensive biochemical studies have resulted in a complete enzymological framework for group II intron ribozymes, and group II intron structures in multiple stages of splicing have been thoroughly characterized through crystallography. With this groundwork in place, it is now possible to initiate a drug discovery program that is designed to identify potent small molecule inhibitors of this promising and novel target. Building on initial small molecule screening efforts (which yielded inhibitors with Ki values of 2-8 µM), we will synthesize the next generation of compounds, optimizing at least two types of initial leads through iterative modification of molecular scaffolds and structure-guided SAR. Small molecule design and synthesis will be done in rapid sequence with subsequent biochemical and cell-based analyses to evaluate potency and efficacy. Our goal in Phase 1 is to identify novel group II inhibitors with Ki values of
Public Health Relevance Statement: Public Health Relevance: There is a great need for potent therapeutics against pathogenic yeast and fungi, which represent a diversifying class of infections that are particularly threatening to immunocompromised individuals such as AIDS patients. We are developing a new class of antimicrobials that inhibit a novel target: the group II self-splicing intron, which is a large catalytic RNA molecule that is unique and central to microbial metabolism.
NIH Spending Category: Biotechnology; Emerging Infectious Diseases; Genetics; Infectious Diseases
Project Terms: Acquired Immunodeficiency Syndrome; Antifungal Agents; antimicrobial; Bacteria; base; Biochemical; Candida albicans; Catalytic RNA; Cells; Chemicals; Chemistry; combat; Complex; Crystallography; design; Development; Drug Design; drug discovery; Enzyme Inhibitor Drugs; Enzyme Inhibitors; Enzymes; Eukaryota; foot; fungus; General Population; Goals; Growth; high throughput screening; Human; Human Cell Line; Immunocompromised Host; in vitro Assay; Individual; Infection; inhibitor/antagonist; Inhibitory Concentration 50; Introns; Investigation; Knowledge; Lead; Mammalian Cell; Metabolic; Metabolism; microbial; Minimum Inhibitory Concentration measurement; Modeling; Modification; Molecular; Morbidity - disease rate; Mortality Vital Statistics; Mycoses; Neonatal; next generation; novel; novel strategies; Organism; pathogen; Patients; Pharmaceutical Chemistry; Pharmaceutical Preparations; pharmacophore; Phase; Play; programs; public health medicine (field); public health relevance; Ribosomes; RNA; RNA Processing; RNA Splicing; scaffold; screening; small molecule; Solid; Source; Staging; Staphylococcus aureus; Structure; Therapeutic; Toxic effect; Vertebrates; Work; Yeasts
