WIDE-BORE NUCLEAR MAGNETIC RESONANCE SPECTROMETER

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Funds are requested for purchase of a wide-bore 200 MHz superconducting nuclear magnetic resonance (NMR) spectrometer. The instrumental capabilities will be complementary to those of a standard-bore 360 MHz spectrometer located in the University of Iowa High-Field NMR Facility. This existing centralized facility is modeled after BRS requirements for a shared usage resource. A Ph.D. level NMR specialist is currently responsible for maintenance, upgrading, consultation, supervision of technicians, and instruction of operators. A broad base of NMR usage currently exists at the University of Iowa. Addition of a high power pulse wide-bore spectrometer would considerably expand opportunities for biomedical researchers ranging from direct observation of whole-cell metabolic processes to elucidation of fundamental chemical reactivity of metalloenzyme active site models. Availability of a large sample volume (20 mm diameter) probe will make possible multinuclear spectral examination of biopolymers (such as heparin, hemoproteins, and lipoproteins) that exhibit low solubility or aggregation tendencies. Spectroscopy of low sensitivity nuclei such as nitrogen-15 in natural products should be practical with the large diameter probe. Various whole-cell and tissue studies are planned including those involving: senescence in anchored cultured mammalian cells, heparin interaction with cultured endothelium cels, neurotoxin interaction with the nerve cells, insulin receptor-insulin effector interactions in cultured cells or membranes, and multinuclear relaxation studies on tissues treated with potential NMR imaging contrast agents. The high power pulse capabilities of the spectrometer would be of particular benefit for paramagnetc NMR measurments, as line widths may be very large and extremely wide sweep widths are required. A cross polarization-magic angle spinning accessory will add new capabilities for spectroscopy of natural products and biopolymers in the solid state. High resolution capabilities of the spectrometer are to be utilized for natural product identification and fluorine-19 observation (not available on our 360 MHz instrument). In addition to providing various new capabilities, the 200 MHz spectrometer would greatly improve accessibility to quality instrumentation, such that available instrument time is not the limiting aspect of research productivity.