Molecular analysis and physicochemical properties of electrophoretic variants of wild soybean Glycine soja storage proteins
Molecular analysis and physicochemical properties of electrophoretic variants of wild soybean Glycine soja storage proteins
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DOI：
10.1021/jf0479620
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发表时间：
2005-05-04
影响因子：
6.1
通讯作者：
Utsumi, S
中科院分区：
文献类型：
--
作者：
Fukuda, T;Maruyama, N;Utsumi, S
栽培大豆（Glycine max）来自野生大豆（Glycine soja），可以与它们杂交产生可育的后代。后者表现出比前者更大的遗传变异，这表明野生大豆含有的贮藏蛋白质的性质不同于或优于栽培大豆的可能性。为筛选适合大豆新品种选育的野生大豆，对390个野生大豆品系的种子蛋白质进行了电泳分析。我们发现了一些含有大豆球蛋白和β-伴大豆球蛋白亚基的电泳变体的细胞系：一个细胞系含有β-伴大豆球蛋白的小α '亚基，两个和五个细胞系分别含有大豆球蛋白的小A3和大A4多肽。β-伴大豆球蛋白和含有这种变异亚基的大豆球蛋白表现出与野生和栽培大豆的主要类型相似的溶解性和乳化能力。含有小A3和大A4的大豆球蛋白在比来自主要类型的野生大豆和栽培大豆的大豆球蛋白低4 ℃的温度下从变性开始得到肩部，尽管它们的热变性中点温度彼此非常相似。主要亚基和变异亚基cDNA的克隆和测序表明，小α ′和小A3在延伸区分别缺少24个氨基酸残基，在高变区缺少4个氨基酸残基，大A4没有相应于电泳迁移率差异的插入片段，但Arg 279和Gln 305分别被谷氨酰胺和组氨酸取代，在高变区。这些表明，即使在高变区的微小差异也会影响蛋白质的热稳定性以及电泳迁移率。
Cultivated soybeans (Glycine max) are derived from wild soybeans (Glycine soja) and can be crossed with them to produce fertile offspring. The latter exhibit greater genetic variation than the former, suggesting a possibility that wild soybeans contain storage proteins with properties different from and better than those of cultivated soybeans. To identify a wild soybean suitable for breeding a new soybean cultivar, we analyzed seed proteins from 390 lines of wild soybeans by electrophoresis. We found some lines containing electrophoretic variants of glycinin and beta-conglycinin subunits: one line containing a small alpha' subunit of beta-conglycinin and two and five lines containing small A3 and large A4 polypeptides of glycinin, respectively. beta-Conglycinin and glycinin containing such variant subunits exhibited solubility and emulsifying ability similar to those of the predominant types of wild and cultivated soybeans. Glycinins containing small A3 and large A4 gave a shoulder derived from the start of denaturation at a temperature 4 degrees C lower than that of glycinin from the predominant types of wild and cultivated soybeans, although their thermal denaturation midpoint temperatures were very similar to each other. Cloning and sequencing of the predominant and variant subunit cDNAs revealed that the small alpha' and the small A3 lacked 24 amino acid residues in the extension region and four amino acid residues in the hypervariable region, respectively, and that the large A4 did not have an insert corresponding to the difference in the electrophoretic mobility but Arg279 and Gln305 were replaced by glutamine and histidine, respectively, in the hypervariable region. These suggest that small differences even in the hypervariable region can affect the thermal stability, as well as the electrophoretic mobilities, of the proteins.