ELECTRON POOR AROMATICS AS POTENTIAL CYCLASE INHIBITORS

贫电子芳烃作为潜在的环化酶抑制剂

• 批准号: 6308889
• 负责人: JOHN H GRIFFIN
• 金额: $ 0.99万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6308889
• 关键词: Mammalia; animal tissue; bacteria; bioengineering /biomedical engineering; biological products; biomedical resource; drug /agent; infection; lipids; plants; spectrometry; structural biology

Oxidosqualene cyclase enzymes catalyze remarkably complex and diverse cyclization/rearrangement processes during the course of sterol and triterpene biosynthesis. These enzymes are of interest from the point of view of mechanistic enzymology and as potential targets for antifungal and anticholesterol agents. Previous work from our laboratory provided the first examples of DNA and predicted amino acid sequences for oxidosqualene cyclase enzymes, in the form of cloned cyclase genes from the yeasts Candida albicans and Saccharomyces cerevisiae. These and other (oxido)squalene cyclase sequences are rich in tryptophan and tyrosine residues, which bear electron-rich aromatic sidechains. This led us to formulate an aromatic hypothesis for active site structure, wherein the indole and phenol sidechains from tryptophan and tyrosine, respectively, serve to direct the formation of and stabilize specific cationic transition states and high energy intermediates along the pathway for cyclization/rearrangement. We are probing the aromatic hypothesis by directed mutagenesis experiments, and also by the development of synthetic probes for the presence of electron-rich aromatics in the cyclizing active site. We have shown that electron-poor aromatic pyridinium ions, which mimic a partially cyclized state, are potent inhibitors of fungal cyclase enzymes and exhibit promising antifungal activity. We plan to expand the range of compounds for synthesis and testing. Mass spectrometry, especially FAB-MS and related techniques, is an important tool for characterization of these nonvolatile synthetic materials.

氧化角鲨烯环化酶催化非常复杂且 过程中发生多种环化/重排过程 甾醇和三萜生物合成。 这些酶很有趣 从机械酶学和潜在的角度来看 抗真菌和抗胆固醇药物的靶点。 之前的作品来自 我们的实验室提供了第一个 DNA 样本并预测了氨基酸 氧化角鲨烯环化酶的酸序列，其形式为 从酵母白色念珠菌中克隆环化酶基因 酿酒酵母。 这些和其他（氧化）角鲨烯环化酶 序列富含色氨酸和酪氨酸残基， 富含电子的芳香族侧链。 这促使我们制定了一个 活性位点结构的芳香族假说，其中吲哚和 色氨酸和酪氨酸的苯酚侧链分别用于 直接形成并稳定特定的阳离子转变 沿途的状态和高能中间体 环化/重排。 我们正在探索芳香假说 定向诱变实验，以及通过开发 用于检测富电子芳香族化合物存在的合成探针 环化活性位点。 我们已经证明了贫电子芳香族 模拟部分环化状态的吡啶鎓离子是有效的 真菌环化酶抑制剂并表现出有前途的抗真菌作用 活动。 我们计划扩大合成和合成化合物的范围 测试。 质谱分析，尤其是 FAB-MS 和相关技术， 是表征这些非易失性的重要工具 合成材料。