DETERMINING THE STRUCTURE OF INFLUENZA B VIRUS HEMAGGLUTININ AT POST-FUSION S

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 乙型流感病毒是人类重要的病原体。它们通过血凝素(HA)介导的膜融合过程进入宿主细胞。这个过程涉及HA的构象发生很大的变化，从中性-pH融合前状态到融合后的低pH状态。 本课题组已成功地测定了乙型流感病毒HA在预融合态、未连接状态以及与两个不同键的受体(GUP-5050)的复合体中的晶体结构。这项研究对乙型流感病毒HA的融合前状态结构以及它的抗原变异和受体结合产生了重要的见解。最后一条遗漏的信息是B型流感HA的低pH结构。 过去，我们还获得了融合后状态下的乙型流感血凝素晶体。全套衍射数据已收集到1.88°(GUP-5637)。然而，晶体受到小晶体的污染，使得我们无法通过分子置换或重原子衍生物来解决结构问题。 经过广泛的试验，我们现在已经成功地在不同的条件下生长出了低pH值的乙型流感HA的晶体。这些晶体在局部X射线源上产生了高达4埃的良好衍射率。因此，需要使用同步加速器X射线源来收集用于原子结构测定的衍射数据。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Influenza B viruses are important pathogens in human. They gain entrance into host cells via a membrane fusion process mediated by hemagglutinin (HA). This process involves a large conformational change of HA, from neutral-pH, pre-fusion state to low-pH post-fusion state. Our group has successfully determined the crystal structures of influenza B HA at pre-fusion state in unliganded state, as well as in complexes with two receptors of different linkages (GUP-5050). That study has yielded important insights into pre-fusion state structures of influenza B HA and into its antigenic variation and receptor binding. The last piece of missing information is of the low-pH structure of influenza B HA. In the past, we have also obtained the crystals of influenza B HA at post-fusion state. A complete set of diffraction data has been collected to 1.88 ¿ (GUP-5637). However, the crystals suffered from contamination of small crystals so that we were unable to solve the structures by molecular replacement or heavy-atom derivatives. After extensive trials, we have now succeeded in growing crystals of low-pH influenza B HA in different conditions. These crystals gave good diffractions up to 4 angstroms at local X-ray sources. So the use of a synchrotron X-ray source is needed to collect diffraction data for atomic structure determination.