3-DIMENSIONAL STRUCTURE OF FAB' FRAGMENT OF A HUMAN IMMUNOGLOBULIN AT 2.8-A RESOLUTION
3-DIMENSIONAL STRUCTURE OF FAB' FRAGMENT OF A HUMAN IMMUNOGLOBULIN AT 2.8-A RESOLUTION
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DOI：
10.1073/pnas.70.12.3305
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发表时间：
1973-01-01
影响因子：
11.1
通讯作者：
SAUL, F
中科院分区：
文献类型：
--
作者：
POLJAK, RJ;AMZEL, LM;SAUL, F
本文报道了一种人骨髓瘤免疫球蛋白Fab‘片段的X射线结晶学分析。将电子密度的傅里叶图与氨基酸序列进行关联，得到三维模型。四个球状亚基对应于轻链和重链的同源区，以四面体构型排列。这些亚基彼此非常相似，共享多肽链折叠的基本模式。在每个亚基中，紧密堆积的氢键多肽链的长序列平行于亚基的主轴。看不到螺旋构象。用这个模型可以解释在其他免疫球蛋白中观察到的不同模式的链间二硫键和不寻常的链内二硫键。轻链和重链中的高可变序列区域出现在分子的一端，空间上非常接近。
The structure of the Fab′ fragment of a human myeloma immunoglobulin was determined by x-ray crystallographic analysis at 2.8-Å resolution. The Fourier map of the electron density was correlated with the aminoacid sequence to obtain a three-dimensional model. Four globular subunits, which correspond to the homology regions of the light and heavy chains, are arranged in a tetrahedral configuration. These subunits closely resemble each other, sharing a basic pattern of polypeptide chain folding. In each subunit, long sequences of tightly packed, hydrogen bonded polypeptide chain run parallel to the major axis of the subunit. No helical conformation can be seen. Different patterns of interchain disulfide linkage and unusual intrachain disulfide bonds that have been observed in other immunoglobulins can be explained with this model. The regions of hypervariable sequences in the light and heavy chains occur at one end of the molecule, in close spatial proximity.