Collaborative Research: A Comprehensive Study of the Structure, Function, and Diversity of Detoxification Enzymes (CYP2B) in Mammalian Herbivores (Neotoma)

在每一顿饭中，成千上万种以植物为食的哺乳动物都面临着被食物产生的天然毒素毒害的可能性。哺乳动物食草动物的普遍觅食习惯，每天吃许多不同的植物物种，被认为是由于他们的肝酶的限制。通才被假设有一个“杰克的所有行业”风格的解毒系统，包括肝酶能够代谢各种植物毒素，但催化效率低。相比之下，专家们认为解毒酶对有限数量的毒素具有更高的效率。这种关于饮食专业化的生化权衡的概念基本上已经成为没有任何实验支持的教条。这项研究将利用从模型物种和人类的药物代谢研究中获得的哺乳动物解毒酶的广泛知识，以及哺乳动物食草动物的最高级野生啮齿动物模型的可用性。长期目标是通过对食草林鼠（Neotoma）细胞色素P450亚家族2B（CYP 2B）中的肝酶进行重点研究，确定膳食暴露于植物毒素如何塑造哺乳动物解毒系统。本次合作研究的具体目标是：1。在氨基酸水平上表征林鼠中的CYP 2B酶。 2.）使用新的代谢组学方法，以确定关键的P450底物的饮食林鼠和比较代谢的植物毒素林鼠CYP 2B酶。 3.）第三章使用Woodrat CYP 2B酶的定点突变和X射线晶体学进行结构-功能分析。这项工作将通过利用尖端的生物化学和结构生物学方法来解决一个长期存在的假设，以首次详细检查野生食草动物的CYP 2B酶，鉴定底物并比较酶功能。最终目标是解决与植物毒素复合的woodrat酶的晶体结构。目前，对哺乳动物解毒酶的了解还很初步。这项工作有可能有助于了解药物代谢在人类的初步数据，这些研究人员对woodrat酶。此外，林鼠是大自然的历史学家;它们储存食物的行为有助于了解过去35，000年来西南沙漠发生的自然变化。犹他州自然历史博物馆将举办一场关于林鼠生态及其对社会重要性的互动展览。PI将指导新一代的学员（高中生通过博士后研究员）进行跨学科研究。该奖项由化学部生命过程计划的化学共同资助。

At every meal, thousands of species of plant-eating mammals confront the possibility of being poisoned by the natural toxins produced by their food. The generalized foraging habit of mammalian herbivores, eating many different plant species on a daily basis, is thought to result from limitations of their liver enzymes. Generalists are hypothesized to have a "jack of all trades" style of detoxification system that consists of liver enzymes able to metabolize a wide array of plant toxins but with low catalytic efficiency. In contrast, specialists are thought to have detoxification enzymes with enhanced efficiency towards a restricted number of toxins. This concept of biochemical tradeoffs with respect to dietary specialization has essentially become dogma without any experimental support. This research will capitalize on the extensive knowledge of mammalian detoxification enzymes gained from studies of drug metabolism in model species and humans, as well as on the availability of a superlative wild rodent model of mammalian herbivory. The long-term objective is to determine how dietary exposure to plant toxins has shaped the mammalian detoxification system through a focused study of liver enzymes in the cytochrome P450 subfamily 2B (CYP2B) in herbivorous woodrats (Neotoma). The specific goals of this collaborative research are: 1.) Characterize the CYP2B enzymes in woodrats at the amino acid level. 2.) Use new metabolomic approaches to identify key P450 substrates in diets of woodrats and compare metabolism of plant toxins by woodrat CYP2B enzymes. 3.) Conduct structure-function analyses using site-directed mutagenesis and X-ray crystallography of woodrat CYP2B enzymes. The work will address a longstanding hypothesis by drawing upon cutting-edge biochemical and structural biology approaches to generate the first detailed examination of CYP2B enzymes of wild herbivores, identify substrates, and compare enzyme function. The ultimate goal is to solve the crystal structures of woodrat enzymes in complex with plant toxins. Currently, knowledge of detoxification enzymes of mammals is rudimentary. The work has the potential to contribute to the understanding of drug metabolism in humans given preliminary data of these investigators on woodrat enzymes. In addition, woodrats are nature's historians; their behavior of storing food has facilitated an understanding of the natural changes that have taken place in the desert southwest over the last 35,000 years. An interactive display about the ecology of woodrats and their importance to society will be developed at the Utah Museum of Natural History. The PIs will mentor a new generation of trainees (high school students through postdoctoral fellows) in interdisciplinary research. This award is co-funded by the Chemistry of Life Processes Program in the Division of Chemistry.