STRUCTURE FUNCTION OF CYTOCHROME P450

细胞色素 P450 的结构功能

• 批准号: 2463623
• 负责人: F K FRIEDMAN
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2463623
• 关键词: carbon monoxide; chemical binding; chemical carcinogen; chemical models; computer simulation; cytochrome P450; drug design /synthesis /production; drug metabolism; enzyme activity; enzyme inhibitors; enzyme substrate complex; flash photolysis; flavones; human tissue; laboratory rat; molecular site; nutrition related tag

The cytochrome P450s metabolize a wide variety of xenobiotic and endogenous compounds. We apply biochemical, biophysical and computational approaches to examine the structure-function relationships which govern the interactions of P450s with substrates, inhibitors, and membrane components. Since these interactions modulate P450 activity, elucidation of their molecular mechanism will aid in a) clarifying the mechanism of P450 mediated drug and carcinogen metabolism, b) defining the role of individual P450s in the metabolism of endogenous and environmental chemicals and c) development of specific P450 inhibitors. We employed the flash photolysis technique to study the kinetics of CO binding to P450s in a natural biological membrane environment, as a unique probe of P450 conformation/dynamics and P450-substrate interactions. The interactions of various drugs and carcinogens with several rat and human P450s were thus assessed, and provided new insights into their modes of binding. Of particular interest is the finding that both P450 1A1, which metabolizes carcinogens, and P450 3A4, which metabolizes a variety of important drugs, are composed of multiple conformers with distinct substrate specificities. This finding provides a basis for P450 recognition of a wide array of structurally diverse substrates. In addition, our results reveal that flavones, a class of dietary phytochemicals, differentially interact with and modulate the activity of specific P450s. We employed computer-aided homology modeling to generate a mammalian P450 model which was used to predict P450 recognition sites for NADPH cytochrome P450 reductase. Synthetic peptides corresponding to these regions on P450 2B1 were prepared and inhibited the P450-reductase interaction. In addition, the substrate binding site of this model was consistent with the known substrate specificity of this P450. This model thus successfully predicts both reductase and substrate binding domains of a mammalian P450.

细胞色素P450能代谢多种异源物质和 内源性化合物。我们应用生化、生物物理和 检验结构功能的计算方法 支配P450与底物相互作用的关系， 抑制剂和膜组件。因为这些相互作用调节了 P450活性，阐明其分子机制将有助于a) 阐明P450介导的药物和致癌物的作用机制 新陈代谢，b)确定个体P450在新陈代谢中的作用 内源性和环境化学品和c)发展 特定的P450抑制剂。 我们利用闪光光解技术研究了CO的动力学 在自然生物膜环境中结合P450，作为一种 P450构象/动力学和P450底物的独特探针 互动。多种药物和致癌物与药物的相互作用 几个大鼠和人的P450因此被评估，并提供了新的 对他们的约束模式的洞察。特别值得关注的是 发现代谢致癌物的P450 1A1和P450 代谢多种重要药物的3A4由以下成分组成 具有不同底物特异性的多个构象。这一发现 为P450在结构上识别广泛的 不同的底物。此外，我们的结果显示，黄酮类化合物是一种 一类饮食中的植物化学物质，与和 调节特定的P450的活性。 我们使用计算机辅助同源建模来产生一种哺乳动物 用P450模型预测NADPH的P450识别位点 细胞色素P450还原酶。与这些相对应的合成肽 制备了P450 2B1上的区域并抑制了P450-还原酶 互动。此外，该模型的底物结合部位为 与该P450的已知底物特异性一致。这 因此，模型成功地预测了还原酶和底物结合 哺乳动物P450的结构域。