Three-dimensional structure of murine anti-p-azophenylarsonate Fab 36-71. 1. X-ray crystallography, site-directed mutagenesis, and modeling of the complex with hapten.
Three-dimensional structure of murine anti-p-azophenylarsonate Fab 36-71. 1. X-ray crystallography, site-directed mutagenesis, and modeling of the complex with hapten.
复制标题
鼠抗对偶氮苯胂酸盐 Fab 36-71 的三维结构。
DOI：
10.1021/bi00229a022
复制
发表时间：
1991
期刊：
影响因子：
2.9
通讯作者：
Margolies,MN
中科院分区：
文献类型：
--
作者：
Strong,RK;Campbell,R;Rose,DR;Petsko,GA;Sharon,J;Margolies,MN
邮政信箱156-29，加州理工学院，帕萨迪纳，加州91125，加拿大国家研究理事会生物科学部，M-54楼，渥太华，安大略K1 A 0 R6，加拿大，罗森斯蒂尔基础医学科学研究中心，布兰德斯大学，沃尔瑟姆，马萨诸塞州02254-9110，波士顿大学医学院病理学和生物化学系，80 East Concord Street，Room K707，Boston，马萨诸塞州02118，和外科，马萨诸塞州总医院和哈佛医学院，波士顿，马萨诸塞州02114接收日期：1990年8月29日;修订的Mandarin pt接收日期：1990年12月26日摘要：抗-β-SMA抗体的抗原结合片段（Fab）的结构偶氮苯胂酸单克隆抗体36-71具有A/J小鼠的主要交叉反应独特型，其R因子为24.8%，分辨率为1.85 A。先前解析的该Fabat的部分结构的分辨率为2.9 μ m（Rose等人，1990）被用作针对高分辨率数据进行细化的初始模型。与半抗原的复合物已被modeledby对接的小分子晶体结构的苯胂酸的天然Fab的结构的基础上，低分辨率的电子密度图的复杂。在该模型中，轻链中的残基Arg-96和重链中的残基Asn-35、Trp-47和Ser-99接触半抗原的胂酸盐部分;在胂酸盐基团和紧密结合的水分子之间发现了另外的键。半抗原的苯基部分与重链中50和106位的两条酪氨酸侧链相结合。在先前实验的基础上，轻链上的残基Arg-96被认为参与了半抗原结合，事实上，这个残基似乎在这个模型中起着至关重要的作用。采用定点诱变的实验直接支持这一结论。重链互补决定区具有新的构象，除了最近解决的抗-对-偶氮苯胂Fab R19之外，以前在免疫球蛋白中未观察到。9（Lascombe等人，1989年）。
Mail Stop 156-29, California Institute of Technology, Pasadena, California 91125, Division of Biological Sciences, National Research Council Canada, Building M-54, Ottawa, Ontario K1A 0R6, Canada, Rosenstiel Basic Medical Sciences Research Center, Brandéis University, Waltham, Massachusetts 02254-9110, Departments of Pathology and Biochemistry, Boston University School of Medicine, 80 East Concord Street, Room K707, Boston, Massachusetts 02118, and Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 Received August 29, 1990; Revised Manuscript Received December 26, 1990 abstract: The structure of the antigen-bindingfragment (Fab) of an anti-/?-azophenylarsonate monoclonal antibody, 36-71, bearing a major cross-reactive idiotype of A/J mice has been refined to an R factor of 24.8% at a resolution of 1.85 A. The previously solved partial structure of this Fabat a resolution of 2.9 Á (Rose et al., 1990) was used as an initial model for refinement against the high-resolution data. The complex with hapten has been modeledby docking the small-molecule crystal structure of phenylarsonic acid into the structure of the native Fab on the basis of a low-resolution electron density map of the complex. In this model, residue Arg-96 in the light chain and residues Asn-35, Trp-47, and Ser-99 in the heavy chain contact the arsonate moiety of the hapten; an additional bond is found between the arsonate group and a tightly bound water molecule. The phenyl moiety of the hapten packs against two tyrosine side chains at positions 50 and 106 in the heavy chain. Residue Arg-96 inthe light chain hadbeen implicated as involved in hapten binding on the basis of previous experiments, and indeed, this residue appears to play a crucial role in this model. Experiments employing site-directed mutagenesis directly support this conclusion. The heavy-chain complementarity-determining regions have novel conformations not previously observed in immunoglobulins except for the recently solved anti-^-azophenylarsonate Fab R19. 9 (Lascombe et al., 1989).