This proposal is for funds to upgrade an existing 2-channel 500 MHz NMR spectrometer to a 4 channel spectrometer with triple-axis gradients, high-order shims, shaped pulses and new probes, within the Center for NMR Spectroscopy at Washington State University. The WSU NMR Center is a central University facility, currently with three NMR spectrometers, newly remodeled space for 5 spectrometers, and a Ph.D.-level Facility Manager. The Center services 13 Departments in 4 Colleges at WSU, with a typical annual usage by some 100 students, postdocs and faculty. The research described here build on existing strengths at WSU, and in particular within the Departments of Biochemistry/Biophysics and of Chemistry, and represents a major initiative to establish the area of structural biology at WSU. The projects in this proposal, the majority of which are funded by NSF, include the use of high resolution liquids NMR to the study of enzymatic reaction mechanisms; the application of standard triple resonance 3D and 4D NMR to the structure determination of a protein-DNA complex, a complex of a partially unfolded protein with a chaperone, and a protein-RNA complex; the application of paramagnetic relaxation effect studies to characterize a ligand-enzyme complex; and the application of gradient-induced diffusion-filtered triple resonance NMR to locate bound water molecules in a model iron-sulfur protein, and use of 2D selective excitation experiments to characterize synthetic natural product diastereomers.