Systemic Upgrade of a Cryo-Electron Microscope

在本申请中，我们申请资金，以确保竞争力的表现，唯一的低温电子断层扫描适合（300千伏）电子显微镜（泰坦Krios G1，赛默飞世尔科技，TFS）的歌德大学法兰克福（GU）和黑森州大学，通过升级的直接电子探测器和计算机/自动加载器电子系统。在GU和吉森大学，许多研究小组利用冷冻电子断层扫描（cryoET）以及单粒子冷冻电子显微镜（cryoEM）进行高端结构和细胞生物学研究。由于cryoEM/ET在结构生物学和结构（原位）细胞生物学中的适用性增强，对系统的分辨率和吞吐量的需求正在增加。 Krios于2011年投入使用，并与马克斯普朗克生物物理研究所合作运营，直到2021年10年合作协议到期。它目前在GU（法兰克福电子显微镜中心，FCEM）的基础设施中心内运行。在过去的十年中，研究论文的重点一直是膜动力学和膜附着复合物。以前成功的项目包括多结构域信号分子的结构，RNA聚合酶I的结构和动力学，对线粒体功能的深入了解，细胞界面的结构和动力学，抗生素耐药性机制等。与此同时，显微镜的电子设备，特别是计算机载物台和自动装载机，已经过时，不再生产。因此，TFS的服务和更换零件不受保证。为了允许Krios的进一步操作，因此需要进行完整的电子设备更换/升级。电子设备更换必须伴随操作系统升级，因为较新的电子部件需要不同的操作系统。此外，计算机台的机械结构显示出大量磨损，导致cryoEM的数据采集时间极其延长，重要的是，禁止cryoET的任何快速倾斜方案，这是目前的标准。除了电子设备升级外，我们还申请升级系统的直接电子探测器。目前的直接电子检测器缺乏性能和吞吐量相比，目前的模型在市场上。至关重要的是，直接电子检测器的服务将于2023年终止，此后供应商（Gatan）将不再支持零件甚至检测芯片的更换。总的来说，我们的Krios的系统升级，如这里所建议的，是在未来十年以竞争方式进行当前和未来项目的最佳性价比。

In this application, we apply for funding to secure the competitive performance of the sole cryo-electron-tomography-suitable (300 kV) electron microscope (Titan Krios G1, Thermo Fisher Scientific, TFS) of the Goethe University Frankfurt (GU) and of the Hessian universities, by an upgrade of the direct-electron detector and the compustage/autoloader electronics of the system. At the GU and the University in Giessen, many groups utilize cryo-electron tomography (cryoET) as well as single-particle cryo-electron microscopy (cryoEM) for high-end structural and cellular biology. Demands on both the resolution and throughput of the system is increasing, driven by the proven enhanced applicability of cryoEM/ET in both structural biology and structural (in-situ) cell biology. The Krios was commissioned in 2011 and was collaboratively operated with the Max Planck Institute of Biophysics until 2021 when the 10-year cooperation agreement expired. It is currently operated within an infrastructure center of the GU (Frankfurt Center for Electron Microscopy, FCEM). The focus of the research papers over the last decade has been on membrane dynamics and membrane-attached complexes. Previous successful projects include the structure of multi-domain signaling molecules, the structure and dynamics of RNA-Polymerase I, deep insights into mitochondrial function, structure and dynamics of cellular interfaces, mechanisms of antibiotic resistance and others. In the meanwhile, the electronics of the microscope, in particular the compustage and autoloader, have become antiquated and are no longer manufactured. Thus, service and replacement parts from TFS are not guaranteed. To allow for further operation of the Krios, a complete electronics replacement/upgrade is therefore necessary. The electronics replacement must be accompanied by an operating system upgrade, as the newer electronic parts require a different operating system. In addition, the mechanics of the compustage shows massive wear, resulting in extremely prolonged data acquisition times for cryoEM and importantly, prohibits any fast-tilting scheme for cryoET which is currently the standard. In addition to the electronics upgrade, we also apply for an upgrade of the direct electron detector of the system. The current direct electron detector lacks both performance and throughput compared to the current models available in the market. Of critical importance is that the service of the direct electron detector terminates in 2023, and thereafter an exchange of parts or even the detection chip will no longer be supported by the vendor (Gatan). Overall, the systemic upgrade of our Krios, as proposed here, is the best value for money to conduct current and future projects in a competitive manner for the next decade.