3-DIMENSIONAL STRUCTURE OF AN ANTIGEN-ANTIBODY COMPLEX AT 2.8-A RESOLUTION
3-DIMENSIONAL STRUCTURE OF AN ANTIGEN-ANTIBODY COMPLEX AT 2.8-A RESOLUTION
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DOI：
10.1126/science.2426778
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发表时间：
1986-08-15
期刊：
影响因子：
56.9
通讯作者：
POLJAK, RJ
中科院分区：
文献类型：
--
作者：
AMIT, AG;MARIUZZA, RA;POLJAK, RJ
用X射线晶体学方法测定了抗原（溶菌酶）和抗溶菌酶单克隆抗体Fab片段之间的复合物的2.8 μ m分辨率的三维结构。与天然晶体形式相比，在溶菌酶的三级结构中没有观察到构象变化。Fab的四级结构是延伸构象。抗体结合位点是一个相当平坦的表面，具有由其氨基酸侧链形成的突起和凹陷。抗原-抗体界面紧密堆积，16个溶菌酶和17个抗体残基紧密接触。抗原接触残基属于溶菌酶多肽链的两段：残基18至27和116至129。抗体的所有互补决定区和高变位置外的两个残基与抗原接触。这些接触中的大多数（17个残基中的10个）由重链，特别是由其第三互补决定区产生。抗原的变异性和抗体的特异性和亲和力的基础上进行了讨论确定的结构。
The 2.8 Å resolution three-dimensional structure of a complex between an antigen (lysozyme) and the Fab fragment from a monoclonal antibody against lysozyme has been determined and refined by x-ray crystallographic techniques. No conformational changes can be observed in the tertiary structure of lysozyme compared with that determined in native crystalline forms. The quaternary structure of Fab is that of an extended conformation. The antibody combining site is a rather flat surface with protuberances and depressions formed by its amino acid side chains. The antigen-antibody interface is tightly packed, with 16 lysozyme and 17 antibody residues making close contacts. The antigen contacting residues belong to two stretches of the lysozyme polypeptide chain: residues 18 to 27 and 116 to 129. All the complementarity-determining regions and two residues outside hypervariable positions of the antibody make contact with the antigen. Most of these contacts (10 residues out of 17) are made by the heavy chain, and in particular by its third complementarity-determining region. Antigen variability and antibody specificity and affinity are discussed on the basis of the determined structure.