3-D STRUCTURES OF VIRAL ANTIGEN-ANTIBODY COMPLEXES

该项目的目的是巩固关于下列问题的初步研究： 流感病毒神经氨酸酶的三维结构和 两种抗体分子（NC 41和NO10）与抗体分子之间的复合物 流感病毒抗原神经氨酸酶。 这是一个延续， 在NIH资助A121659下支持的工作。 具体而言，将开展三项工作。 (1)先前确定的NC 41 Fab-神经氨酸酶的结构 将根据可用的X射线衍射确定复合物 分辨率为2.8A。 将分析由此产生的结构 为了能够准确地描述蛋白质中的构象变化， 神经氨酸酶，据信伴随着这种结合， 特定抗体（NC 41），并试图找到一个结构 当抗体与酶活性降低相关时， 绑定。 这种改进也将允许准确地描述 Fab片段中的V-模块四级结构，其具有 据报道是不寻常的。 由于VL和 在复合的NC 41抗体的情况下观察到的VH结构域 可能是由抗原引起的， 这种Fab结构和其他Fab结构之间的联系可能会提供一些基本的 对免疫识别的深入了解 (2)NClO Fab-神经氨酸酶复合物的结构将是 坚定而优雅 该结构的发现将增加 到非常小的抗体-抗原复合物结构数据库， 并有助于澄清适应性拟合的相对重要性 相对于刚性键合， 大分子复合物 (3)神经氨酸酶逃逸突变体的结构将是 用其他单克隆抗体完成和结晶实验 抗体和甲型流感病毒神经氨酸酶将继续。 从这项工作中产生的知识将（a）允许 该流感病毒的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， 这种病毒和其他可变病毒（如艾滋病毒），（c）有助于提供 对免疫识别的一般理解，至少在 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.