Cholesterol Oxidase Loop Residues and Catalysis

胆固醇氧化酶环残基和催化

• 批准号: 7119323
• 负责人: NICOLE S SAMPSON
• 金额: $ 1.92万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7119323
• 关键词: X ray crystallography; active sites; chemical kinetics; cholesterol; conformation; enzyme activity; enzyme mechanism; enzyme model; enzyme structure; enzyme substrate complex; flavins; hydroxysteroid dehydrogenases; lipid bilayer membrane; membrane structure; molecular assembly /self assembly; site directed mutagenesis

DESCRIPTION (provided by applicant): Cholesterol oxidase is a flavoenzyme that catalyzes the oxidation and isomerization of cholesterol to cholest-4-en-3-one. Cholesterol oxidase is used commercially for the determination of serum cholesterol concentrations, is insecticidal, and is used to study membrane structure. Recent evidence suggests that cholesterol oxidase may be involved in the pathogenesis of some microorganisms such as Rhodococcus equi and Mycobacterium tuberculosis. The studies proposed will provide a precise molecular model of the lipid requirements for activity and of the pathway to flavin oxidation. These models are important for the development of cholesterol oxidase as a commercial product, as a useful and reliable tool in the study of cellular membranes for monitoring lipid rafts, for investigating the role of cholesterol oxidase in bacterial pathogenesis, and for developing anti-bacterial inhibitors. The specific hypotheses that will be tested are that 1) cholesterol oxidase can distinguish between cholesterol-containing lipid domains of different composition in the same membrane, i.e., between liquid-disordered domains and liquid-ordered domains (rafts); 2) the enzyme employs a large interface to associate with the lipid bilayer during catalysis; and 3) a gated tunnel between the solvent and the flavin at the active site controls oxygen access.

描述（由申请方提供）：胆固醇氧化酶是一种黄素酶，可催化胆固醇氧化和异构化为胆甾-4-烯-3-酮。胆固醇氧化酶在商业上用于测定血清胆固醇浓度，具有杀虫作用，并用于研究膜结构。最近的证据表明，胆固醇氧化酶可能参与一些微生物如马红球菌和结核分枝杆菌的发病机制。这项研究将提供一个精确的分子模型的脂质活动的要求和途径的黄素氧化。这些模型对于胆固醇氧化酶作为商业产品的发展是重要的，作为用于监测脂筏的细胞膜的研究中的有用且可靠的工具，用于调查胆固醇氧化酶在细菌发病机制中的作用，以及用于开发抗菌抑制剂。将要检验的具体假设是：1）胆固醇氧化酶可以区分同一膜中不同组成的含胆固醇脂质结构域，即，在液体无序结构域和液体有序结构域（筏）之间; 2）酶在催化过程中采用大的界面与脂质双层缔合;以及3）溶剂和活性位点处的黄素之间的门控隧道控制氧进入。