Structural Features of a Conformation-dependent Antigen Epitope on ORFV-B2L Recognized by the 2E4 mAb
Structural Features of a Conformation-dependent Antigen Epitope on ORFV-B2L Recognized by the 2E4 mAb
复制标题
2E4 mAb 识别的 ORFV-B2L 上构象依赖性抗原表位的结构特征
DOI：
10.1038/s41598-019-52446-5
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发表时间：
2019-11-06
影响因子：
4.6
通讯作者：
Cui, Yudong
中科院分区：
文献类型：
--
作者：
Yu, Yongzhong;Zhao, Wenbo;Cui, Yudong
在此之前，我们成功地制备了一种单克隆抗体，命名为2 E4，它可以直接识别羊口疮病毒（ORFV）的主要包膜蛋白B2 L，但关于其表位的信息很少。在这里，我们通过组合程序精心绘制了2 E4表位，并确定了功能结合结构域和关键氨基酸残基。结果表明，模拟表位肽与B2 L的N-端氨基酸84 VDVQSKDKDADELR 97紧密相连，表明该表位具有构象或空间结构依赖性。随后，我们将这些发现与B2 L抗原性预测的结果相结合，设计了三个截短的B2 L片段（F1，F2和F3），使用2 E4筛选，发现只有F1片段适合于晚期阶段。丙氨酸扫描突变表明D94残基对2 E4表位的结构至关重要。其他参与的残基，包括K61、E62和D92，与D94一起负责使2 E4结合，并作为协同地使能与整个2 E4表位结合的因子。在本文中，我们描述了，为第一次，ORFV构象表位的架构，它也是预期的mAb 2 E4和它的表位可以用于与ORF控制有关的应用。
Previously, we successfully prepared a monoclonal antibody (mAb) named 2E4, that directly recognizes the major envelope protein B2L of the orf virus (ORFV), but there is little information about its epitope. Here, we meticulously mapped the 2E4 epitope through combinatorial programs and identified the functional binding domain and a key amino acid residue. Briefly, the simulated epitope peptide closely resembles84VDVQSKDKDADELR97located at the N-terminus of B2L, strongly suggesting that the epitope is conformationally or spatially structure-dependent. Subsequently, we combined these findings with the results from the antigenicity prediction of B2L to design three truncated fragments of B2L (F1, F2 and F3) selected using 2E4, and only the F1 fragment was found to be eligible for the advanced stage. Alanine-scanning mutagenesis suggested that the D94residue is structurally crucial for the 2E4 epitope. The other participating residues, including K61, E62, and D92, together with D94were responsible for enabling 2E4 binding and served as factors that synergistically enabled binding to the whole 2E4 epitope. In this paper, we describe, for the first time, the architecture of an ORFV conformational epitope, and it is also expected that mAb 2E4 and its epitope can be used for applications relating to orf control.