The Kansas State University (KSU) Biomolecular NMR Facility, which has served more than 23 separate NIH-funded research projects, request funding to purchase a 5 mm triple resonance cryogenic probe with enhanced carbon sensitivity and salt tolerant proton coil for an existing Varian 500 NMR System(R) . This acquisition of a cryogenic probe will afford a 2-3 fold enhancement in sensitivity compared with conventional probes and will be of great use to eight major users and many other NIH supported investigators at this campus studying mass-limited biomolecules having less stability and/or low solubility and biomacromolecules that show concentration-dependent aggregation. Currently our users are constrained with the present instrumentation due to the limited sensitivity of the conventional probe. Many of our local researchers supported by NIH funding are forced to go to distant facilities for 2D and 3D NMR studies on their diluted samples, as our 500 MHz NMR spectrometer equipped with a conventional probe is limited in its ability to perform these experiments in a timely manner and in some cases not at all. The cryogenic probe is essential for our 500 MHz console to perform long hours 2D and 3D NMR experiments for studying solution structure and dynamics of large biomolecules and other compounds available in limited amount. The leading performance benefits of the upgraded 500 MHz NMR spectrometer with the requested cryogenic probe will be: a) improved signal-to-noise ratio in the NMR spectra, b) reduced experimental time for multi-dimensional NMR experiments, c) lowered detection limit, and d) enhanced capability to acquire NMR data on diluted samples and on biomacromolecules with low solubility and or less stability. In brief this upgrade will facilitate KSU Biomolecular NMR facility in performing multi-dimensional NMR experiments on proteins/peptides and other biomacromolecules available in low concentration with best possible sensitivity on the existing instrument. The funding of this project will provide a shared instrumentation necessary to complete on going NIH supported research programs at KSU and to elevate inter-institutional biomedical research collaborations between KSU NMR facility and nearby institutions. PUBLIC HEALTH RELEVANCE: Most of the research projects in this application aim at understanding the structure and function of a variety of protein domains relevant to human health. These include chitin binding domain and 2-1, 3 glucan binding domain of insect proteins, lysine-rich domain of the SARS- CoV nucleocapsid protein, channel forming peptides, amyloid beta peptides and biophysical mechanism of protein-protein or protein-peptide interactions, particularly in immunity and inflammatory diseases and in insects as disease vectors. The acquisition of a state-of-the-art cryogenic probe for our existing 500 MHz NMR console will significantly enhance or create new feasibility of such studies of broad importance in a number of human diseases, such as Alzheimer's dementia, ataxia, ischemia, and cystic fibrosis. .