PROJECT SUMMARY/ABSTRACT This proposal requests funds to purchase a JEOL JEM-1400 Transmission Electron microscope (TEM) with cryogenic capabilities to replace our 33-year-old analog JEOL JEM-100CX II TEM with a digital camera housed in the Electron Microscopy Center Core Facility at North Dakota State University (NDSU). This state- of-the-art instrument will expand the research capabilities of a number of NIH funded investigators at NDSU. It will provide reliable routine access to a TEM capable of recording images of cryogenically preserved samples (Cryo-EM) in addition to continue to provide reliable negative staining capabilities. The TEM and supplied supporting accessories will allow investigators to routinely prepare, screen, and characterize samples that have be `flash-frozen'. Thus, NDSU investigators will be able to expand into areas of research involving Cryo- EM single particle reconstruction, Cryo-EM tomography, and Cryo-EM microcrystal electron diffraction. The requested instrument is capable of screening samples and data collection for all these techniques. This structural data provides critical information for understanding protein structure-function relationships as well as chemical structure, soft polymer structure, and overall cellular arrangements that control biomedical related processes. Currently, NDSU does not have this instrumentation and there is no Cryo-EM facility within a reasonable distance for routine travel: the two closest cryoTEMs to our institution are located at 240 miles/4 hours drive time and 750 miles/11 hours drive time. Therefore, users are currently relying on access to Cryo- EM via long distance collaboration with external user fees. This is inefficient and prohibitively expensive for investigators. Access to this instrument will provide a gateway into the NIH High Resolution Cryo-Electron Microscopy Program by allowing routine access to a screening scope needed to collect the preliminary data necessary to make full use of the national service centers. As an IDeA eligible institution in an AREA state this resource can have a transformative impact on the type of science being performed at NDSU. The instrument will be housed in a core facility managed by two full time scientists, supported by NDSU. Thus, access and maintenance of the instrument are under the direct supervision knowledgeable experts thus protecting the longevity of the instrument. Projects of immediate relevance that will be addressed involve 1) protein:protein interactions involved in bacterial cell surface signaling, 2) understanding agonist/antagonist influence on protein:protein interactions involve in a G-protein coupled receptor, 3) protein:protein interactions involved in autophagy regulation, and 4) nanoparticle assemblies for drug delivery. Overall, our user group represents investigators in five departments across three colleges and the instrument will facilitate research in areas related to pharmacology to materials. The presence of Cryo-EM instrument at NDSU will greatly enhance the research directions of these and other projects of NIH relevance. It will significantly increase student training opportunities and research productivity of faculty.