Crystal structure of soybean proglycinin alaB1b homotrimer
Crystal structure of soybean proglycinin alaB1b homotrimer
复制标题
DOI：
10.1006/jmbi.2000.4310
复制
发表时间：
2001-01-12
影响因子：
5.6
通讯作者：
Utsumi, S
中科院分区：
文献类型：
--
作者：
Adachi, M;Takenaka, Y;Utsumi, S
大豆球蛋白是11 S球蛋白家族的一员.前大豆球蛋白的晶体结构通过X射线晶体学以2.8埃分辨率测定，R因子为0.199，自由X因子为0.250。在晶体的不对称单元中发现了三聚体分子。三聚体模型包含三个A1 aB 1b亚基，包含1128个氨基酸残基和34个水分子。同源三聚体蛋白质的组成原聚体围绕3重对称轴排列，尺寸为95埃× 95埃× 40埃。原聚体模型由5个片段组成，这些片段大致对应于基于各种11 S球蛋白的序列比对的保守区域。原聚体的核心由两个卷曲的β-桶和两个延伸的螺旋结构域组成。前大豆球蛋白的这种结构与属于7S球蛋白家族的刀豆球蛋白和菜豆蛋白的结构相似，强烈支持7S和11 S球蛋白都来自共同祖先的假设。11 S球蛋白家族中保守的链间和链内二硫键被清楚地观察到。结果表明，含有链间二硫键的面（IE面）比含有链内二硫键的面含有更多的疏水残基。这表明，一个成熟的六聚体是由加工后的IE面之间的相互作用形成的。(C)北京：科学出版社.
Soybean glycinin is a member of the 11 S globulin family. The crystal structure of proglycinin was determined by X-ray crystallography at 2.8 Angstrom resolution with an R-factor of 0.199 and a free X-factor of 0.250. A trimer molecule was found in an asymmetric unit of crystals. The trimer model contains three A1aB1b subunits and comprises 1128 amino acid residues and 34 water molecules. The constituent protomers of the homo-trimeric protein are arranged around a 3-fold symmetry axis with dimensions of 95 Angstrom x 95 Angstrom x 40 A. The protomer model is composed of five fragments which correspond roughly to conserved regions based on the sequence alignment of various 11 S globulins. The core of the protomer consists of two jelly-roll beta -barrels and two extended helix domains. This structure of proglycinin is similar to those of canavalin and phaseolin belonging to the 7 S globulin family, strongly supporting the hypothesis that both 7 S and 11S globulins are derived from a common ancestor. The inter and intra-chain disulfide bonds conserved in the 11S globulin family are clearly observed. It is found that the face with the inter-chain disulfide bond (IE face) contains more hydrophobic residues than that with the intra-chain disulfide bond. This suggests that a mature hexamer is formed by the interaction between the IE faces after processing. (C) 2001 Academic Press.