Molecular Analysis of Plant Triacylglycerol Biosynthetic Enzymes

菜籽油是由油菜籽植物油菜的种子制成的。菜籽油除了是一种宝贵的食物来源外，还是大型农业产业的一部分，每年为加拿大经济贡献超过190亿美元。我们的长期目标是提高油菜籽的产量和质量。位于细胞膜中的蛋白质制造菜籽油。这些蛋白质是酶，它们共同作用产生脂肪，包括甘油三酯（TAG），这是菜籽油中的主要脂肪。在本研究项目中，将详细研究TAG生成途径中的最后一个蛋白——甘蓝型油菜DGAT1，以了解其功能。为了准确理解油菜籽中的主要脂肪TAG是如何产生的，我们需要对制造油菜籽油的蛋白质有一个分子上的了解。我们的研究实验室在确定蛋白质的三维结构方面具有专长。结构将使我们能够检查蛋白质中执行产生TAG功能的部分。为了大量产生，我们在酵母中表达了油菜植物DGAT1蛋白。有了这种蛋白质，我们已经确定它产生的脂肪与油菜籽中的脂肪相似。这种蛋白质将被结晶，以便看到它的三维结构。它的结构测定将需要使用x射线照射晶体。将在没有和存在脂肪底物的情况下寻找结构。一旦我们能看到菜籽油生产过程中蛋白质的整体形状和细节，我们就能设计出生产更多菜籽油或偏好不饱和脂肪的蛋白质，而不饱和脂肪是食品工业所需的质量。这种更高效的DGAT1蛋白将在油菜植物中进行工程设计，并将用于油菜油生产的评估。确定其他TAG产生酶的结构也将进行，目的是影响TAG在油菜植物中的生产。未来的研究将集中在TAG生物合成途径中的其他酶。总的来说，本研究有可能提高油菜植物种子中的菜籽油产量，从而提高油菜作物的产量。这将对油菜籽作物产业产生强烈影响，并为加拿大带来强大的经济优势。这个项目也将有助于训练高素质的人员。

Canola oil is made in the seed of the canola plant Brassica napus. Besides being a valuable food source, canola oil is part of a large agricultural industry that contributes to Canada’s economy over 19 billion dollars annually. Our long term goals are to enhance the oil quantity and quality in the canola plant. Proteins located in the membranes of cells make canola oil. These proteins are enzymes that work together to make fats including triacyglycerol (TAG), a predominant fat in canola oil. In this research program, the last protein in pathway toward TAG production, Brassica napus DGAT1, will be studied in detail to gain insight into its function. To understand precisely how TAG, the main fat in canola, is generated, we require a molecular understanding of the protein that makes canola oil. Our research lab has expertise in determining the three-dimensional structure of proteins. A structure will allow us to examine the part(s) of the protein that carries out the function of producing TAG. In order to generate large quantities, we have expressed the canola plant DGAT1 protein in yeast. With this protein, we have determined that it produces fats similar to that found in the canola plant. This protein will be crystallized in order to see its three-dimensional structure. Its structural determination will require the use of X-ray exposure to the crystals. Structures will be sought both in the absence and presence of fat substrates. Once we can see the overall shape and details of the protein involved in canola oil production, we can then design protein that makes more canola oil or has preferences for unsaturated fat, a desired quality in food industry. This more efficient DGAT1 protein will be engineered in the canola plant, which will be assessed for canola oil production. Determining the structure of other TAG producing enzymes will also be conducted with the goals of influencing TAG production in canola plants. Future studies will focus on other enzymes in the TAG biosynthetic pathway. Overall, this study has the potential to improve the canola oil production in the seed of the canola plant, resulting in enhanced yield in the canola crops. This would have a strong effect on the canola crop industry and a strong economic advantage for Canada. This project will also contribute to the training of highly qualified personnel.