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Studies on molecular structure of soybean glycinin by protein engineering.

蛋白质工程研究大豆甘氨酸分子结构。

基本信息

批准号：
63560085
负责人：
UTSUMI Shigeru
金额：
$ 1.28万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63560085/
关键词：
Soybean proteins Glycinin Protein engineering Gene expression Molecular assembly

项目摘要

One of the major objectives of the food industries is the enrichment of the functional properties and nutritional value of soybean storage proteins. Of the storage proteins, glycinin contains more methionines, which is limiting amino acid of soybean proteins. Therefore, glycinin is targeted to improve the nutritional and functional properties of soybean proteins. To attain this goal theoretically, molecular structure of glycinin should be elucidated. In this research, the object is the elucidation of glycinin molecular structure by means of protein engineering.1. The author attempted to express cDNAs encoding glycinin subunits in microorganisms (Escherichia coli and Saccharomyces cerevisiae). It was necessary for the expression of glycinin cDNA in E. coil to delete nucleotide sequences corresponding to the signal sequence. Then, a high-level expression system was established by controlling the cultivation conditions of E. coli cells harboring the expression plasmids. In Saccharomyces cerevisiae, the signal sequence of the expressed Iycinin subunit was el cleaved at the right processing site.2. The expressed protein from glycinin cDNA in E. coil was purified to homogeneity. The purified protein self-assembled and its secondary structure and fundamental properties were similar to those of the native glycinin. This indicated that the E. coli expression system of glycinin cDNA may be employed for the studies of glycinin molecular structure.3. Expression plasmids carrying the glycinin cDNAs modified to change the molecular structure of glycinin were constructed. At present, the modified proteins are being purified. The ability of the self-assembly of the modified proteins and their higher structures will be investigated to elucidate the molecular structure of glycinin.

食品工业的主要目标之一是丰富大豆贮藏蛋白的功能特性和营养价值。大豆贮藏蛋白中，大豆球蛋白含有较多的蛋氨酸，是大豆蛋白的限制性氨基酸。因此，大豆球蛋白是改善大豆蛋白营养和功能特性的目标。要从理论上实现这一目标，必须阐明大豆球蛋白的分子结构。本研究的目的是利用蛋白质工程的方法来阐明大豆球蛋白的分子结构.作者尝试在微生物（大肠杆菌和酿酒酵母）中表达编码大豆球蛋白亚基的cDNA。大豆球蛋白cDNA在大肠杆菌中的表达是必需的。卷曲以删除对应于所述信号序列的核苷酸序列。通过控制E. coli细胞中表达。在酿酒酵母中，表达的Iycinin亚基的信号序列在正确的加工位点被切割。将大豆球蛋白cDNA在E.将coil纯化至均匀。纯化的蛋白质自组装，其二级结构和基本性质与天然大豆球蛋白相似。这表明E.大豆球蛋白cDNA的大肠杆菌表达系统可用于大豆球蛋白分子结构的研究。构建了携带经修饰以改变大豆球蛋白分子结构的大豆球蛋白cDNA的表达质粒。目前，修饰蛋白正在纯化中。我们将研究这些修饰蛋白的自组装能力及其高级结构，以阐明大豆球蛋白的分子结构。