Functional and modelling studies of the binding of human monoclonal anti-DNA antibodies to DNA
Functional and modelling studies of the binding of human monoclonal anti-DNA antibodies to DNA
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DOI：
10.1016/0161-5890(95)00138-7
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发表时间：
1996-03-01
影响因子：
3.6
通讯作者：
Isenberg, DA
中科院分区：
文献类型：
--
作者：
Kalsi, JK;Martin, ACR;Isenberg, DA
研究了四种人单克隆抗DNA抗体的抗原结合特异性与其中两种抗体的结合位点的结构方面之间的关系。竞争ELISA用于检查两种IgM mAb（WRI-176和RT-79）和两种IgG mAb（D5和B3）对广泛的多核苷酸的反应性。发现mAb WRI-176和RT-79主要结合ssDNA，优先结合poly（dT），而D5和B3结合ss-和dsDNA以及Z-DNA的组分。mAb B3还表现出对富含AT的核苷酸的偏好。生成WRI-176和B3的Fv区的计算机模型。RT-79和D5的模型未生成，因为这些mAb中长CDR-H3环的结构无法预测。B3结合位点含有在位置CDR-L1- 27 A、CDR-L2-54和CDR-H2-53处侧接三个丝氨酸的凹槽。使用交互式分子图形，B-DNA沿着V-H/V-L界面的平面沿着对接到B3抗原结合位点中，而Z-DNA在与该方向成大约90度处最佳拟合。这些模型提供了一个假设来解释单个自身抗体结合两种不同抗原的能力。此外，B3的碱基特异性方面也可以解释。WRI-176 Fv区的模型揭示了相对平坦的表面，在该表面上存在大量疏水性和芳香族残基。特别是Trp-H52在表面上突出。这可能通过碱基堆积相互作用参与ssDNA结合。该模型允许鉴定用于定点诱变的潜在靶标。版权所有（C）1996 Elsevier Science Ltd.
The relationships between the antigen-binding specificities of four human monoclonal anti-DNA antibodies and the structural aspects of the combining sites of two of these were examined. Competition ELISAs were used to examine the reactivities of two IgM MAbs (WRI-176 and RT-79) and two IgG mAbs (D5 and B3) to a wide range of polynucleotides. The mAbs WRI-176 and RT-79 were found to bind predominantly ssDNA, with a preference for poly (dT), whilst D5 and B3 bound components of both ss- and dsDNA, and Z-DNA. The mAb B3 also exhibited a preference for AT rich nucleotides. Computer models were generated for the Fv regions of WRI-176 and B3. Models for RT-79 and D5 were not generated as the structure of the long CDR-H3 loops in these mAbs could not be predicted. The B3 combining site contains a groove flanked by three arginines at positions CDR-L1-27A, CDR-L2-54 and CDR-H2-53. Using interactive molecular graphics, B-DNA was docked into the B3 antigen combining site along the plane of the V-H/V-L interface, whilst Z-DNA was best-fitted at approximately 90 degrees to this direction. The models provide a hypothesis to explain the ability of a single autoantibody to bind two different antigens. In addition, aspects of the base specificity of B3 may be explained. The model of the WRI-176 Fv region revealed a relatively flat surface, on which a large number of hydrophobic and aromatic residues were present. Trp-H52, in particular, is prominent on the surface. This may participate in ssDNA binding through base stacking interactions. The models allow identification of potential targets for site-directed mutagenesis. Copyright (C) 1996 Elsevier Science Ltd.