PLASTIC PIPETTE TIPS AS SAMPLE MOUNTS FOR PROTEIN CRYSTALLOGRAPHY X-RAY DIFFRACT

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。 对由六种不同透明等级的聚合物制成的相同尺寸的塑料毛细管进行了测试，以确定哪种聚合物产生最小的X射线背景，并且最适合于生产用于在低温下收集蛋白质晶体学X射线衍射数据的样品容器。测试的聚合物为：丙烯腈丁二烯苯乙烯（ABS）、聚甲基丙烯酸甲酯（丙烯酸）、聚酰胺（PA）、高抗冲聚苯乙烯（HIP）、聚碳酸酯（PC）和低密度聚乙烯（LPDE）。 在SSRL BL 7 -1上收集数据。每个样品在100 K的温度下暴露于0.976 A X射线约30秒。监测入射强度并改变暴露时间，以确保每个样品接受相等的X射线剂量。注意暴露来自每个测试样品的相同体积的塑料。在暴露过程中，每个塑料都旋转了5度。散射强度由位于距样品251 mm处的Q315 CCD检测器测量，给出1.37 A的最大分辨率。 还评估了每个塑料容器的光学性质。 这项工作是与Hauptman Woodward医学研究所的研究人员合作完成的，目的是开发一种可用于晶体生长和X射线衍射质量筛选的小型塑料毛细管。毛细管将用作手动移液器和自动液体处理机器人的移液器吸头，使晶体生长的溶液能够轻松地吸入内部。 对于X射线数据收集，毛细管的较大端安装在金属底座上，组件安装在SSRL盒或单圆盘样品存储容器内，并与SSRL自动样品安装系统兼容，用于自动筛选和远程访问数据收集。

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. Plastic capillaries of identical size produced from six different clear grades of polymers were tested to determine which polymer produces the smallest x-ray background and is the most suitable for the production of sample containers used for protein crystallography x-ray diffraction data collection at cryogenic temperatures. The polymers tested were: Acrylonitrile butadiene styrene (ABS), Polymethyl methacrylate (Acrylic), Polyamide (PA), High Impact Polystyrene (HIP), Polycarbonate (PC), and Low Density Polyethylene (LPDE). Data were collected on SSRL BL7-1. Each sample was exposed to 0.976 A x-rays for about 30 seconds at a temperature of 100 K. The incident intensity was monitored and the exposure time varied to ensure each sample received an equivalent x-ray dose. Care was taken to expose the same volume of plastic from each sample tested. Each plastic was rotated five degrees during the exposure. The scattered intensity was measured by a Q315 CCD detector located at a distance of 251 mm from the sample giving a maximum resolution of 1.37 A. The optical properties of each of the plastic containers were also assessed. This work was done in collaboration with researchers at the Hauptman Woodward Medical Research Institute with the goal of developing a small plastic capillary that can be used both for crystal growth and x-ray diffraction quality screening. The capillary will be used as a pipette tip with both manual pipetters and automated liquid handling robots enabling solutions for crystal growth to be easily drawn inside. For x-ray data collection, the larger end of the capillaries fits onto a metal base and the assembly fits inside the SSRL cassette or uni-puck sample storage container and is compatible with the SSRL automated sample mounting system for automated screening and remote access data collection.