Crystal structure of soybean 11S globulin: Glycinin A3B4 homohexamer
Crystal structure of soybean 11S globulin: Glycinin A3B4 homohexamer
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DOI：
10.1073/pnas.0832158100
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发表时间：
2003-06-10
影响因子：
11.1
通讯作者：
Utsumi, S
中科院分区：
文献类型：
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作者：
Adachi, M;Kanamori, J;Utsumi, S
大多数植物种子含有11S球蛋白作为其营养的主要储存蛋白。大豆球蛋白属于11S球蛋白家族，由5种亚基组成.我们确定了2.1埃分辨率的大豆球蛋白A3B4亚基的同六聚体的晶体结构。晶体结构表明，六聚体具有32点群对称性，由两个三聚体面对面堆叠而成。界面隐藏了高度保守的链间二硫键。基于该结构，我们提出了一个巧妙的面对面的机制控制的六聚体形成的11 S球蛋白的移动的无序区域的移动后的翻译后处理的三聚体的一侧。静电分析的面孔表明，链间含二硫键的面具有高的正电位在酸性pH值下，这会诱导解离的六聚体成三聚体，可能是容易受到蛋白酶种子吸胀后。这种解离可能导致11S球蛋白在萌发和幼苗生长过程中作为胚中的储存蛋白的降解和移动。
Most plant seeds contain 11S globulins as major storage proteins for their nutrition. Soybean glycinin belongs to the 11 S globulin family and consists of five kinds of subunits. We determined the crystal structure of a homohexamer of the glycinin A3B4 subunit at 2.1-Angstrom resolution. The crystal structure shows that the hexamer has 32-point group symmetry formed by face-to-face stacking of two trimers. The interface buries the highly conserved interchain disulfide. Based on the structure, we propose that an ingenious face-to-face mechanism controls the hexamer formation of the 11 S globulin by movement of a mobile disordered region to the side of the trimer after posttranslational processing. Electrostatic analysis of the faces suggests that the interchain disulfide-containing face has high positive potential at acidic pH, which induces dissociation of the hexamer into trimers that may be susceptible to proteinases after seed imbibition. This dissociation might result in the degradation and mobilization of 11S globulins as storage proteins in embryos during germination and seedling growth.