CRYSTAL-STRUCTURE OF THE EXTRACELLULAR REGION OF THE HUMAN CELL-ADHESION MOLECULE CD2 AT 2.5-ANGSTROM RESOLUTION
CRYSTAL-STRUCTURE OF THE EXTRACELLULAR REGION OF THE HUMAN CELL-ADHESION MOLECULE CD2 AT 2.5-ANGSTROM RESOLUTION
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DOI：
10.1016/s0969-2126(94)00076-x
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发表时间：
1994-08-15
期刊：
影响因子：
5.7
通讯作者：
DAVIS, SJ
中科院分区：
文献类型：
--
作者：
BODIAN, DL;JONES, EY;DAVIS, SJ
背景：T淋巴细胞抗原CD 2是一种参与体内免疫反应的粘附分子。人和大鼠CD 2同源物的胞外区仅具有45%的序列同一性，并结合不同的蛋白质配体。比较人和大鼠可溶性CD 2（sCD 2）的结构应该提供洞察到细胞表面recognization.Results的结构基础：因此，我们确定了一种形式的人sCD 2的晶体结构，在每个糖基化位点的单个N-乙酰葡糖胺残基的2.5埃分辨率与R-因子为19.3%。它由两个免疫球蛋白超家族结构域组成，与大鼠sCD 2的结构域相似，但两个同源物中结构域的相对方向相差高达20度。涉及平面，高度带电，配体结合GFCC 'C''面的结晶相关的人sCD 2分子重复的相互作用，在不同的晶格中，观察到在大鼠sCD 2 crystals.Conclusions：分子内的灵活性似乎是一个保守的功能的CD 2。分子之间的头对头相互作用代表了这种结构类别的粘附分子之间相互作用的一般模型。配体特异性可能受到结合面上带电残基分布的影响。
Background: The T-lymphocyte antigen CD2 is an adhesion molecule implicated in immune responses in vivo. The extracellular regions of the human and rat homologues of CD2 share only 45 % sequence identity and bind different protein ligands. Comparison of the human and rat soluble CD2 (sCD2) structures should provide insights into the structural basis of cell surface recognition.Results: We therefore determined the crystal structure of a form of human sCD2 with single N-acetylglucosamine residues at each glycosylation site to 2.5 Angstrom resolution with an R-factor of 19.3 %. It is composed of two immunoglobulin superfamily domains similar to those of rat sCD2, but the relative orientation of the domains in the two homologues differs by up to 20 degrees. An interaction involving the flat, highly charged, ligand binding GFCC'C'' faces of crystallographically related human sCD2 molecules duplicates, in a different lattice, that observed in the rat sCD2 crystals.Conclusions: Intramolecular flexibility appears to be a conserved feature of CD2. The head-to-head interaction between molecules represents a general model for interactions between adhesion molecules of this structural class. Ligand specificity may be influenced by the distribution of charged residues on the binding face.