Toxicological importance of CYP3A4 catalysis and inhibition

方案主任/首席调查员(Sevrioukova，Irina F.)： 项目摘要 人细胞色素P450 3A4(CYP3A4)是主要的和临床上最相关的药物代谢酶， 因其极端的底物混杂和变构行为而臭名昭著。药物和其他外来生物 还可以刺激和抑制CYP3A4活性，这往往会导致不良的药物相互作用 (DDIS)、化学毒性和治疗失败。尽管进行了广泛的研究，但CYP3A4抑制和 激活机制仍不完全清楚。这项提议以使用结构生物学为中心。 解决细胞色素P3A4研究两个领域的关键问题的方法。AIM 1将调查CYP3A4 基于结构合理设计HIV酶抑制剂利托那韦类似物的抑制机制 其有效抑制细胞色素P3A4的能力纯属巧合。我们将确定结构性决定因素 合理设计和研究利托那韦类化合物的构效关系 化合物，并根据我们的发现，建立了一个有效的CYP3A4特异性的3D药效团模型 可用于早期预测/消除候选药物中的抑制潜力的抑制剂 开发更有效的药物增强剂。AIM 2将利用一种集成的生化、化学 研究CYP3A4底物结合协作性的标记、结构和计算方法 变构。我们最近的结构发现证实了先前绘制的外围区域的重要性 并确定了三个可用于底物/效应器对接的新的内部位置。我们将评估这一角色 以及这些区域的相对重要性，通过评估它们的修改/中断如何影响CYP3A4 构象，底物结合协同性，化学计量和新陈代谢。这项研究概述了 从基础科学和翻译科学的角度来看，提案都很重要，因为它将填补 知识差距，并提供对CYP3A4在结构上的可塑性和适应性的基本见解 不同的配体，阐明复杂配体结合行为和氧化的分子机制 动力学，并帮助开发更好的工具，用于蛋白质-配体接触的电子预测，代谢稳定性和 DDI在候选药物中具有提高疗效和减少脱靶效应的潜力。 OMB编号0925-0001/0002(08/12版批准至2015年8月31日)页面续格式页面

Program Director/Principal Investigator (Sevrioukova, Irina F.): Project Summary Human cytochrome P450 3A4 (CYP3A4) is the major and most clinically relevant drug-metabolizing enzyme, notoriously known for its extreme substrate promiscuity and allosteric behavior. Drugs and other xenobiotics can also stimulate and inhibit CYP3A4 activity, which frequently leads to undesired drug-drug interactions (DDIs), chemical toxicity and therapeutic failures. Despite extensive investigations, the CYP3A4 inhibitory and activation mechanisms remain incompletely understood. This proposal centers on using structural biology approaches to address key issues in both areas of CYP3A4 research. Aim 1 is set to investigate the CYP3A4 inhibitory mechanism via rational structure-based design of analogues of ritonavir, an HIV protease inhibitor whose ability to potently inhibit CYP3A4 was purely coincidental. We will identify structural determinants required for potent inhibition by rationally designing and investigating structure-activity relations of ritonavir-like compounds and, based on our findings, build a 3D-pharmacophore model for a potent CYP3A4-specific inhibitor that can be used for early prediction/elimination of the inhibitory potential in drug candidates and for development of more effective pharmacoenhancers. Aim 2 will utilize an integrated biochemical, chemical labeling, structural and computational approach to investigate the CYP3A4 substrate binding cooperativity and allosterism. Our recent structural findings confirmed the importance of the previously mapped peripheral area and identified three novel inner sites that could serve for substrate/effector docking. We will evaluate the role and relative importance of these areas by assessing how their modification/disruption affects CYP3A4 conformation, substrate binding cooperativity, stoichiometry and metabolism. The research outlined in this proposal is important from both the basic and translational science perspectives, because it will fill the knowledge gaps and provide fundamental insights into plasticity and adaptability of CYP3A4 to structurally diverse ligands, clarify molecular mechanisms underlying the complex ligand binding behavior and oxidative kinetics, and help develop better tools for in silico prediction of protein-ligand contacts, metabolic stability and DDI potential in drug candidates to improve their efficacy and reduce off-target effects. OMB No. 0925-0001/0002 (Rev. 08/12 Approved Through 8/31/2015) Page Continuation Format Page