3-D STRUCTURES OF VIRAL ANTIGEN-ANTIBODY COMPLEXES

该项目的目的是巩固以下方面的初步研究 流感病毒神经氨酸酶的 3-d 结构 两个抗体分子(NC41和NO10)之间的复合物和 流感病毒抗原神经氨酸酶。 它是一个延续 NIH 拨款 A121659 资助的工作。 具体来说，将做好三项工作。 (1)先前确定的NC41 Fab-神经氨酸酶的结构 配合物将根据可用的 X 射线衍射来定义 数据分辨率为2.8A。 将分析所得结构 能够准确描述构象变化 神经氨酸酶被认为伴随着这种结合 特定抗体（NC41），并试图找到结构 抗体加入后酶活性降低的相关性 绑定。 细化还可以准确描述 Fab 片段中的 V 模块四级结构，其中具有 被报告为不寻常。 由于 VL 和 VL 的不常见配对 在复合 NC41 抗体的情况下观察到的 VH 结构域 可能是抗原诱导的，具体差异 该结构与其他 Fab 结构之间可能会提供一些基本的 对免疫识别的见解。 (2)NClO Fab-神经氨酸酶复合物的结构为 确定并精炼。 该结构的发现将增加 关于抗体-抗原复合物结构的非常小的数据库， 并有助于阐明适应性配件的相对重要性 与刚性粘合相比，形成这一类重要的 大分子复合物。 (3) 神经氨酸酶逃逸突变体的结构为 与其他单克隆完成和结晶实验 抗体和甲型流感病毒神经氨酸酶将继续存在。 这项工作产生的知识将（a）允许 该流感病毒两个重叠表位的描述 抗原，(b) 增加了我们对抗原变异的理解 这种病毒和其他变异病毒（例如 HIV），(c) 有助于提供 对免疫识别的一般了解，至少在这方面 B 细胞免疫，以及 (d) 有助于未来合理设计 合成疫苗。

The aim of this project is to consolidate preliminary studies on the 3-d structures of influenza virus neuraminidase and of complexes between two antibody molecules (NC41 and NOlO) and the influenza virus antigen neuraminidase. It is a continuation of work supported under NIH grant A121659. Specifically, three tasks will be undertaken. (1) The previously determined structure of NC41 Fab-neuraminidase complex will be defined against the available X-ray diffraction data to 2.8A resolution. The resulting structure will be analyses to enable an accurate description of conformational changes in the neuraminidase which are believed to accompany the binding of this particular antibody (NC41), and to attempt to find a structural correlate of the decrease in enzyme activity when the antibody binds. The refinement will also permit an accurate description of the V-module quaternary structure in the Fab fragment, which has been reported to be unusual. Since the uncommon pairing of VL and VH domains observed in the case of the complexed NC41 antibody might have been induced by antigen, the detailed differences between this and other Fab structures may provide some fundamental insights into immune recognition. (2) The structure of NClO Fab-neuraminidase complex will be determined and refined. The findings from this structure will add to the very small database on antibody-antigen complex structures, and help to clarify the relative importance of adaptable fitting versus rigid bonding in the formation of this important class of macromolecular complexes. (3) The structures of escape mutants of neuraminidase will be completed and crystallization experiments with other monoclonal antibodies and influenza A virus neuraminidases will continue. The knowledge generated from this work will (a) permit a description of two overlapping epitopes of this influenza virus antigen, (b) add to our understanding of antigenic variation in this and other variable viruses (such as HIV), (c) help to provide a general understanding of immune recognition, at least as regards B cell immunity, and (d) aid in the future rational design of synthetic vaccines.