MOLECULAR FUNCTION OF RECEPTORS AND TRANSPORTERS AT CHEMICAL SYNAPSES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 该项目涉及三种不同且独特的整合膜蛋白：（1）细菌转运蛋白（“X4”）;（2）真核P2 X离子通道;和（3）真核全长离子型谷氨酸受体（iGluR）。对于这三个项目来说，科学或技术目的是相同的  测量最高分辨率的衍射数据集。这提出了一个巨大的挑战，因为所有这些晶体都很弱  它们是完整膜蛋白的晶体，并且晶体体积的大部分由水溶液和无序去污剂和脂质分子组成。特别是，对于X4项目，我们的目标是收集NE-CAT微焦点光束线上的高分辨率本地数据和ID-24光束线上的多波长数据。对于P2 X项目，由于我们有低分辨率的相位，我们正在测量微焦点光束线上的本地数据集（有和没有激动剂和调制剂）。在谷氨酸受体项目的情况下，我们正在使用已知的结构的细胞外结构域的分子置换，以获得相位信息，因此重点是测量单波长数据的大量激动剂，拮抗剂和变构调节剂复合物。 这三个项目都很重要。据我所知，X4和P2 X蛋白质的折叠目前尚不清楚，即确定的折叠可能是独特的，因此这些初始结构将为两个大而非常重要的膜蛋白类提供结构蓝图。此外，详细的结构分析将为分子机制提供深入和未知的见解。在谷氨酸受体的情况下，完整受体的结构将提供深刻的见解的离子通道门控及其调制的机制，以及到离子渗透和块。

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. This project involves three different and unique integral membrane proteins: (1) a bacterial transport protein ('X4'); (2) a eukaryotic P2X ion channel; and (3) a eukaryotic, full-length ionotropic glutamate receptor (iGluR). For all three projects, the scientific or technical purpose is the same  to measure the highest resolution diffraction data sets possible. This presents a great challenge because all these crystals diffract weakly  they are crystals of integral membrane proteins and a large fraction of the crystal volume is composed of aqueous solution and disordered detergent and lipid molecules. In particular, for the X4 project, we are aiming to collect high resolution native data on the NE-CAT microfocus beam line and multiwavelength data on the ID-24 beam line. For the P2X project, since we have low resolution phases, we are measuring native data sets (with and without agonists and modulators) on the microfocus beam line. In the case of the glutamate receptor project, we are using the known structures of the extracellular domains in molecular replacement to obtain phase information, and thus the emphasis is on measuring single wavelength data on a large number of agonist, antagonist and allosteric modulator complexes. The importance of all three projects is substantial. To the best of my knowledge, the folds for the X4 and P2X proteins are currently unknown, i.e. the determined folds are likely to be unique, and thus these initial structures will provide the architectural blueprint for two large and very important classes of membrane proteins. The detailed structural analysis, in addition, will provide deep and as-of-yet unknown insights into molecular mechanism. In the case of the glutamate receptor, the structure of the intact receptor will provide profound insights into the mechanism of ion channel gating and its modulation, as well as into ion permeation and block.