1)军事科学院军事医学研究院,北京 100071;2)联勤保障部队第九六一医院卫勤处,齐齐哈尔 161000
北京市科技新星计划(20240484733)资助项目。
1)Academy of Military Medical Sciences, Academy of Military Sciences, Beijing 100071, China;2)Department of Medical Service, The 961st Hospital of Joint Logistics Support Force, Qiqihar 161000, China
This work was supported by a grant from Beijing Nova Program Funding Project (20240484733).
目的 基于甲型流感病毒神经氨酸酶(neuraminidase,NA)蛋白抗原抗体复合物结构数据,探究抗原蛋白表位与抗体的空间结构识别关系。方法 完整收集SAbDab数据库中NA蛋白抗原抗体复合物结构数据,对蛋白质结构进行处理分析,获取抗原表位和相应抗体配位氨基酸序列和空间分布信息,统计分析结合抗体序列、基因使用频率、氨基酸使用偏好性和互补决定区(CDR)氨基酸长度;分析抗体结合的热点区域,进一步对抗体配位空间结构相似性进行计算和层次聚类,深入探究抗原表位与抗体的空间识别关系,通过生物膜干涉(BLI)实验验证靶向不同抗原表位的抗体的识别特异性。结果 SAbDab数据库中甲型流感病毒NA蛋白的抗原抗体复合物结构数据以H3N2、H7N9、H1N1亚型为主,抗原表位的热点位置主要集中在催化活性位点区域,抗体物种来源以人源和鼠源为主,鼠源抗体VJ基因组合使用频率最高的是IGHV1-12*01/IGHJ2*01,人源抗体VJ基因组合使用频率最高的是IGHV1-69*01/IGHJ6*01。结合在催化活性位点区域内与结合在催化活性位点区域以外其他区域的抗体,在重链CDR氨基酸长度与氨基酸使用偏好性方面存在显著差异。抗原表位与抗体配位具有特定的识别关系,部分相似的抗体配位结构特异性地识别相同的表位,可在结构上观察到结合区域的重叠,BLI实验也验证了这类抗体对表位的竞争结合。结论 NA蛋白抗原表位位点分布以催化活性位点及周围环状区域为主,空间构象互补与静电相互作用在抗体与抗原的催化活性区域识别和结合过程中发挥重要作用。抗原与抗体存在不依赖于抗体唯一序列的空间识别关系,不同序列的抗体也可能形成识别同一抗原表位的局部空间结构。
Objective This study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes.Methods Structural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments.Results The collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments.Conclusion The antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.
朱拯,陈郑珊,张冠英,房婷,樊璞,毕磊,崔越,李泽亚,苏纯懿,迟象阳,于长明.甲型流感病毒神经氨酸酶抗原蛋白表位与抗体的结构空间识别[J].生物化学与生物物理进展,2025,52(4):957-969
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