In the work undertaken here, NMR has been used to ascertain the structure of some 1,2,4-triazoles. The investigation provides information concerning the structure of potentially tautomeric triazoles such as hydroxy- and aminotriazole. Connected with this aspect of triazole chemistry is the larger problem of mesohydric tautomerism. The present study also yields information for a comparison of substituent effects in triazoles, N-heteroaromatic substances and benzene.

by Chan Chun-Chung, Jerry. / The "59" in Co in title is superscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 157-170). / DESCRIPTIVE NOTE --- p.iii / Chapter CHAPTER ONE: --- A BRIEF SURVEY OF TRANSITION METAL NMR STUDIES --- p.1 / Chapter 1.0 --- Introduction --- p.1 / Chapter 1.1 --- Solution NMR Of Transition Metals --- p.2 / Chapter 1.1.1 --- Parametrization Model of Chemical Shifts --- p.4 / Chapter 1.2 --- Theoretical Calculation of the Chemical Shielding Constants of Transition Metals --- p.6 / Chapter 1.3 --- Solid State NMR of Transition Metals --- p.7 / Chapter 1.4 --- Scope of the Thesis --- p.9 / Chapter CHAPTER TWO: --- THEORY AND BACKGROUND --- p.10 / Chapter 2.0 --- Introduction --- p.10 / Chapter 2.1 --- The Origin of Chemical Shielding --- p.10 / Chapter 2.1.1 --- The Ramsey Shielding Tensor Equation with Gauge Origin Chosen at the Nucleus --- p.13 / Chapter 2.1.2 --- The Ramsey Shielding Tensor Equation with Arbitrary Gauge Origin --- p.20 / Chapter 2.1.3 --- The Physical Picture Associated with the Ramsey Shielding Equation --- p.21 / Chapter 2.2 --- Ab Initio Shielding Calculation --- p.24 / Chapter 2.2.1 --- Coupled Hartree-Fock Method --- p.25 / Chapter 2.2.2 --- Gauge Dependence Problem --- p.27 / Chapter 2.2.3 --- Post Hartree-Fock Methods --- p.29 / Chapter 2.3 --- Density Functional Theory --- p.30 / Chapter 2.3.1 --- The Hohenberg-Kohn Theorems --- p.30 / Chapter 2.3.2 --- The Kohn-Sham Approach --- p.35 / Chapter 2.3.3 --- Approximation to the Exchange- Correlation Energy --- p.37 / Chapter CHAPTER THREE: --- INTERPRETATION OF 59Co NMR SHIELDING USING THE HARD AND SOFT ACID-BASE CONCEPT -- INSIGHT INTO THE RELATIVE MAGNITUDE OF THE NEPHELAUXETIC AND THE SPETROCHEMICAL EFFECT --- p.39 / Chapter 3.0 --- Introduction --- p.39 / Chapter 3.1 --- Theory --- p.42 / Chapter 3.2 --- Evaluation of the Model --- p.45 / Chapter 3.3 --- Application to the Studies of trans-[Co(en)2X2](3+2n) + in Different Solvents and the Determination of the Spectrochemical Trend --- p.54 / Chapter 3.4 --- "Simultaneous Determination of the Nuclear Quadrupole Coupling Constant, Chemical Shift Anisotropy and Rotational Correlation Time in trans-Na[Co(acac)2(NO2)2]， trans- [Co(acac)2(NH3)2 ]I, trans-[Co(acac)2(CH3NH2)2]I and trans-[Co(acac)2(NH3)(NO2)]" --- p.59 / Chapter 3.5 --- Summary --- p.64 / Chapter CHAPTER FOUR: --- DENSITY FUNCTIONAL STUDY OF THE ELECTRONIC STRUCTURES OF [Co(NH3)5X](3+n)+ USING DIFFERENT POPULATION AND BONDING ANALYSIS METHODS --- p.66 / Chapter 4.0 --- Introduction --- p.66 / Chapter 4.1 --- Computational Details --- p.69 / Chapter 4.2 --- Bond Covalency Analysis of [Co(NH3)5X](3+n)+ --- p.71 / Chapter 4.2.1 --- Mayer Bond Order Analysis --- p.71 / Chapter 4.2.2 --- Natural Population Analysis --- p.73 / Chapter 4.2.3 --- Natural Bond Orbital Analysis --- p.76 / Chapter 4.2.4 --- Mulliken Population Analysis --- p.82 / Chapter 4.3 --- Summary --- p.86 / Chapter CHAPTER FIVE: --- DENSITY FUNCTIONAL STUDY OF 59Co CHEMICAL SHIELDING CONSTANTS --- p.87 / Chapter 5.0 --- Introduction --- p.87 / Chapter 5.1 --- SOS-DFPT-IGLO Calculations of 59Co NMR Shielding Parameters of Hexacoordinated Diamagnetic Co(III) Complexes --- p.90 / Chapter 5.1.1 --- Computational Details --- p.91 / Chapter 5.1.2 --- Basis Sets and XC Functional for 59Co Shielding Calculations --- p.92 / Chapter 5.1.2.1 --- 59Co NMR Shielding Calculation of [Co(CN)6]3- --- p.92 / Chapter 5.1.2.2 --- Nearest Neighbour Effect --- p.94 / Chapter 5.1.3 --- Comparison of the Calculated and Experimental 59Co Chemical Shift Anisotropy and Asymmetry Factor --- p.95 / Chapter 5.1.4 --- Comparison of the Calculated and Experimental 59Co Isotropic Chemical Shifts --- p.97 / Chapter 5.1.4.1 --- Reproducing the Experimental Trend by SOS-DFPT-IGLO? --- p.99 / Chapter 5.1.4.2 --- Local and Non-local Paramagnetic Shielding Contributions --- p.103 / Chapter 5.1.5 --- General Comments of the Calculated Results --- p.104 / Chapter 5.2 --- A Comparative Study of the Calculation of 59Co NMR Shielding Constants of Hexacoordinated Diamagnetic Co(III) Complexes Using SOS-DFPT-IGLO and Hybrid DFT-GIAO Methods --- p.105 / Chapter 5.2.1 --- Computational Details --- p.106 / Chapter 5.2.2 --- Comparison of DFT-IGLO-Becke/Perdew and DFT-GIAO-Becke/Perdew --- p.106 / Chapter 5.2.3 --- DFT-GIAO-B3LYP --- p.108 / Chapter 5.2.4 --- Summary --- p.111 / Chapter CHAPTER SIX: --- STUDY OF THE SHIELDING CONSTANTS OF DIAMAGNETIC HEXACOORDINATED Co(III) COMPLEXES BY POLYCRYSTALLINE 59Co NMR AND DENSITY FUNCTIONAL THEORY --- p.112 / Chapter 6.0 --- Introduction --- p.112 / Chapter 6.1 --- Solid State NMR Technique for Quadrupolar Nuclei --- p.112 / Chapter 6.2 --- Static Powder Lineshape Analysis --- p.114 / Chapter 6.2.1 --- Excitation of Quadrupolar Nuclei --- p.114 / Chapter 6.2.1.1 --- Selective and Partially Selective Excitation --- p.116 / Chapter 6.2.2 --- Spin Echo Pulse Sequence --- p.117 / Chapter 6.2.3 --- Lineshape Simulation --- p.120 / Chapter 6.3 --- Solid State 59Co NMR Study of Hexacoordinated Co(III) Complexes --- p.124 / Chapter 6.3.1 --- Experimental --- p.124 / Chapter 6.3.2 --- Simulation Details --- p.125 / Chapter 6.3.2.1 --- [Co(NH3)4CO3]NO3 --- p.127 / Chapter 6.3.2.2 --- [Co(en)2CO3]Cl and [Co(en)2NO3](NO3)2 --- p.130 / Chapter 6.3.2.3 --- cis-[Co(en)2(N02)2]NO3 and cis-[Co(en)2(N3)2]NO3 --- p.133 / Chapter 6.3.2.4 --- K3[Co(CN)6] --- p.133 / Chapter 6.3.2.5 --- "Co(acac)3， K3[Co(NO2)6] and [Co(en)3]X3 (X = C1, Br, I)" --- p.137 / Chapter 6.4 --- Dependence of 59Co Shielding Calculation on Basis Sets and Exchange Correlation Functional --- p.143 / Chapter 6.4.1 --- CSA and η calculations of [Co(NH3)4C03] Br --- p.144 / Chapter 6.4.2 --- CSA and η Calculations of [Co(NH3)6]C13 --- p.147 / Chapter 6.4.3 --- Shielding Calculations of Larger Co(III) Complexes at B3PW91/6311+G* Level --- p.149 / Chapter 6.5 --- Summary --- p.153 / Chapter CHAPTER SEVEN: --- CONCLUSION AND FUTURE WORK --- p.154 / BIBLIOGRAPHY --- p.157 / APPENDIX A MATHEMATICAL DETAILS FOR THE DERIVATION OF THE RAMSEY SHIELDING EQUATION --- p.171 / APPENDIX B ANALYSIS OF THE SIGN OF PARAMAGNETIC AND DIAMAGNETIC SHIELDING --- p.178 / APPENDIX C GENERALIZATION OF EQUATION [3.4] TO INCLUDE THE EFFECT OF π-BONDING --- p.181 / APPENDIX D GEOMETRY OPTIMIZATION OF CoH AND CoO --- p.183 / APPENDIX E A NON-LINEAR ITERATIVE LEAST SQUARE FITTING PROCEDURE FOR THE ANALYSIS OF SOLID STATE NMR STATIC SPECTRUM OF QUADRUPOLAR NUCLEUS --- p.187

The structural dynamics of proteins and other macromolecules typically serve crucial roles for their respective biological function. While rigid protein structures are used in classic “lock and key” descriptions of enzymology and receptor-ligand interactions, more and more evidence suggest that the majority of molecular interactions occur on the spectrum between induced-fit binding and conformational selection binding. This model of biomolecular interaction requires, to differing degrees, conformation plasticity and dynamics of the protein itself. To characterize the determinants and implications of protein dynamics, there exists no more suited biophysical technique than nuclear magnetic resonance (NMR) spectroscopy. This method is capable of probing the individual atomic nuclei of proteins in a site-specific manner. Furthermore, NMR spectroscopy is unique in being able to access timescales from picoseconds to seconds, providing information on events from bond vibration and libration to protein folding and ligand binding. The breadth of biophysical information accessible by NMR spectroscopy has led to its widespread use in the study of protein dynamics. The work presented herein involves i) the use of NMR for investigation of structure and dynamics in two separate biological systems that demonstrate a high degree of flexibility for folded proteins and ii) the improvement of pulse sequences and methodology for better characterizing picosecond to nanosecond backbone and side-chain dynamics. The organizing principle of this work, which is best exemplified in the structural studies of the piRNA-pathway protein Gametocyte-specific factor 1, is the unmatched capability of NMR spectroscopy to decipher molecular details within dynamic protein systems. First, the molecular structure and RNA-binding properties of gametocyte-specific factor 1 (GTSF1) of the piRNA effector pathway were investigated. A partially disordered protein with two Zn finger domains, the work presented here describes the isolation of a GTSF1 protein construct amendable to study by NMR spectroscopy. Chemical shift assignment of GTSF1 allowed site-specific observation of amide correlations, which established the basis for NMR structure calculation of GTSF1 and the evaluation of binding to candidate RNA sequences, with goal of the identification of an in vivo RNA binding partner for GTSF1. The work presents compelling data that indicate GTSF1 Zn finger 1 specifically binds a motif GGUUC(G/A) RNA, which in this study was found in the T-arm loop of transfer RNA. Zn finger 2 is affected by the interaction with RNA, but the available structural and binding data indicate that the second Zn finger is a more dynamic, breathable entity, supported by cysteine chemical shift and structural differences between the two GTSF1 Zn fingers. Although it’s currently speculative, the function of GTSF1 might first require binding of RNA to the more stable Zn finger 1, which then leaves Zn finger 2 poised for binding to another molecular species. tRNA-derived fragments that include the T-arm TC loop have been recently implicated in silencing of transposable elements in mammalian cells. GTSF1, which was identified in a genetic screen for piRNA-pathway proteins as vitally required for gene silencing, might plausibly act as a sensor of transcription of transposable elements and help initiate Piwi-piRISCs-mediated chromatin modification and heterochromatin formation. Next, NMR spectroscopy is used to investigate protein thermostability in psychrophilic (cold-loving) cytochrome c552. Isolated from the bacterium Colwellia psychrerythraea (Cp), previous work has implicated two conserved Cpcyt c552 methionine residues, which are both conserved across psychrophilic and psychrotolerant cytochromes, as acting in dynamical ligand substitution with a third methionine that is the axial heme ligand. It is proposed that elevated backbone dynamics in these methionine residues and the ability for them swap into the axial ligand position accounts for an uncharacteristically high melting temperature (Tm) compared to meso- and thermophile c-type cytochromes. Progress was made in NMR sample preparation and backbone chemical shift assignment of both redox states of Cpcyt c552, and insight from 1D 1H NMR experiments focused on the heme group bound to Cp cytochrome c552 is discussed. Additionally, chemical shifts are used to predict protein dynamics as a first test of a multiple methionine axial ligand hypothesis. Initial data analysis predicts relatively large measures of Random Coil Index for residues surrounding the native axial heme ligand, and shows the hyperfine shifts localized to the residues surrounding the heme. Future experiments will selectively record methyl group dynamics of methionine residues for elucidation of rate constants of methionine substitution and to determine the structural properties of this minor conformation. Finally, two NMR methodology studies are presented in this thesis: a novel simultaneous-acquisition TROSY pulse sequence for measurement of backbone spin relaxation rates (R1 and {1H}-15N heteronuclear NOE) and a side-chain 2H spin relaxation method for using multifield experimental datasets for better sampling of the spectral density function. Together, these pulse sequences represent significant advancements in NMR measurement of microscopic rate constants and more nuanced detail of protein dynamics.

No description available.

Au Yuen-yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 140-152). / Abstracts in English and Chinese. / Abstract --- p.iii / Acknowledgements --- p.v / Chapter Chapter One: --- General Background and Introduction --- p.1 / Chapter 1 -1 --- Introduction --- p.1 / Chapter 1-2 --- Three-Bond Coupling Constants (3J) --- p.1 / Chapter 1-2-1 --- Development of the Karplus Equation --- p.1 / Chapter 1-2-2 --- Application of3J in the Conformational Analysis of Nucleic Acid --- p.4 / Chapter 1-2-3 --- Problem of Accuracy for3 J Measurement --- p.7 / Chapter 1-3 --- Two-Bond Coupling Constants (2J) --- p.7 / Chapter 1-3-1 --- The Use of the Projection Method --- p.7 / Chapter 1-3-2 --- 2J Coupling Constant Involving Hydrogen Bonds --- p.8 / Chapter 1-4 --- One-Bond Coupling Constants (1J) --- p.10 / Chapter 1-5 --- Conclusion --- p.11 / Chapter Chapter Two: --- Experimental Section / Chapter 2-1 --- Introduction --- p.12 / Chapter 2-2 --- Heteronuclear Multiple-Quantum Coherence (HMQC) Experiment --- p.12 / Chapter 2-3 --- Experimental Section --- p.15 / Chapter 2-3-1 --- Sample Preparation --- p.15 / Chapter 2-3-2 --- NMR Spectroscopy --- p.16 / Chapter Chapter Three: --- Theory of Nuclear Spin-Spin Coupling Constants --- p.18 / Chapter 3-1 --- Introduction --- p.18 / Chapter 3-2 --- Application of Finite Perturbation Theory on Nuclear Spin-Spin Coupling --- p.18 / Chapter 3-3 --- Methodology --- p.22 / Chapter Chapter Four: --- DFT and NMR Study of1JCH Coupling Constants --- p.28 / Chapter 4-1 --- Introduction --- p.28 / Chapter 4-2 --- Nomenclature and Definition of Structural Parametersin DNA and RNA --- p.28 / Chapter 4-2-1 --- "Nomenclature, Symbols and Atomic Numbering Schemes" --- p.28 / Chapter 4-2-2 --- Definition of Torsion Angles and their Rangesin Nucleotides --- p.31 / Chapter 4-2-3 --- Description of the Furanose Ring --- p.31 / Chapter 4-3 --- Results and Discussion --- p.37 / Chapter 4-3-1 --- Basis Set Effect --- p.37 / Chapter 4-3-2 --- Relative Conformational Energy Profiles --- p.37 / Chapter 4-3-3 --- Comparison of the Dependence of 1JCH Coupling Constants on Conformational Changes With and Without the DNA Backbone --- p.40 / Chapter 4-3-4 --- Effect of Backbone 3'- and 5'-Phosphate --- p.42 / Chapter 4-3-5 --- Effect of Glycosidic Torsion Anglex --- p.49 / Chapter 4-3-6 --- Effect of Ring Conformation with Fixed Glycosidic Torsion Anglex --- p.52 / Chapter 4-3-7 --- Effect of Torsion Angle α --- p.52 / Chapter 4-3-8 --- Effect of Torsion Angle β --- p.53 / Chapter 4-3-9 --- Effect of Torsion Angle γ --- p.56 / Chapter 4-3-10 --- Effect of Torsion Angle ε --- p.59 / Chapter 4-3-11 --- Effect of Torsion Angle ζ --- p.61 / Chapter 4-3-12 --- Effect of Base Pairing --- p.65 / Chapter 4-3-13 --- Effect of Base Stacking from the (n-1) and (n+1) Base --- p.65 / Chapter 4-3-14 --- Comparison of Experimental and Theoretical Data --- p.68 / Chapter 4-4 --- Conclusion --- p.74 / Chapter Chapter Five: --- DFT Study of 2JCH and 3JCH Coupling Constants --- p.79 / Chapter 5-1 --- Introduction --- p.79 / Chapter 5-2 --- Results and Discussion on 2JCH Coupling Constants --- p.79 / Chapter 5-2-1 --- Effect of Backbone 3'- and 5'-Phosphate --- p.79 / Chapter 5-2-2 --- Effect of Ring Conformation with Fixed Glycosidic Torsion Anglex --- p.82 / Chapter 5-2-3 --- Effect of Glycosidic Torsion Anglex --- p.87 / Chapter 5-2-4 --- Effect of Torsion Angleγ --- p.87 / Chapter 5-2-5 --- Effect of Torsion Angle ε --- p.90 / Chapter 5-2-6 --- Effect of Base Pairing --- p.90 / Chapter 5-2-7 --- Effect of Base Stacking from the (n-1) and (n+1) Base --- p.90 / Chapter 5-3 --- Results and Discussion on 3JCH Coupling Constants --- p.95 / Chapter 5-3-1 --- Effect of Backbone 3'- and 5'-Phosphate --- p.95 / Chapter 5-3-2 --- Effect of Ring Conformation with Fixed Glycosidic Torsion Anglex --- p.95 / Chapter 5-3-3 --- "Effect of Different Torsion Angles (X,α,β,γ,ε,and ζ)" --- p.100 / Chapter 5-3-4 --- Effect of Base Pairing --- p.100 / Chapter 5-3-5 --- Effect of Base Stacking from the (n-1) and (n+1) Base --- p.105 / Chapter 5-4 --- Conclusion --- p.105 / Chapter Chapter Six: --- Conclusion --- p.111 / Appendix A Product Operator Formalism on HMQC Pulse Scheme --- p.113 / Appendix B Finite Perturbation Theory --- p.115 / Appendix C Supplementary Figures of Chapter Four --- p.118 / Appendix D Some of the NMR Spectra --- p.134 / References --- p.140

The purpose of this thesis was two fold: (i) The synthesis and characterization of SF5 containing dienes. (ii) The characterization of hydro/fluorocarbon compounds containing SF5/S02F groups via their 13C NMR spectra. A new SF5CH2CHBrCH2CF=CF2 was prepared and characterized as a precursor to new dielectric polymers. This new adduct was made from the reaction of pentafluorothio bromide with l,l,2-trifluoro-1,4-pentadiene. A SF5-diene was prepared from the reaction of pentafluorothio chloride with acetylene. This reaction involves a radical addition mechanism. The SF5 group is bonded to the carbon atom carrying the most hydrogens. SF5 - dienes are capable of undergoing different reactions, such as polymerization. Fluorocarbon sulfonyl fluorides (RS02F), which have been synthesized in our lab, were characterized by their 13C NMR spectra. The 13C NMR data of these sulfonyl fluorides show chemical shift values for the methyl and methylene groups next to a fluoroalkyl sulfonyl fluoride group in the 52.8-65.7 ppm range. The spectra showed that the inductive effect of electronegative substituents has a major influence on the 1Jc-F and 1Jc-H coupling. Infrared, 1H, 19F and 13C nuclear magnetic resonance and mass spectra are presented to support the assigned structure for the new compounds, SF5CH=CHCH=CHC1 and SF5CH2CHBrCH2CF=CF2.

The behavior of surfactants in solution has been and still is of scientific, technological, and industrial interest. The micelle forming compounds sodium N( octyloxycarbonyl)sarcosinate (NaOcSarc), and sodium N-(decyloxycarbonyl)sarcosinate (NaDecSarc) show in aqueous solution two lH NMR N-methyl peaks arising from a possible cis- or trans-conformation. The relative population of the N-methyl peaks depends mostly on the concentration of surfactant indicating micelle formation. Upon heating the two peaks start to coalesce and finally appear as one single peak . The temperature range in which this phenomenon occurs is from 25°C to 65°C. The primary interest of this study was to determine the activation parameters of rotation about the carbonyl-nitrogen (C-N) bond. Dynamic nuclear magnetic resonance spectroscopy was employed to approach this problem. A complete bandshape analysis was performed in order to calculate the free energy (G++), enthalpy (H++), and entropy (S++) of activation. The effect of a different counter ion (Li+) and sodium chloride salt addition were tested for possible changes of the activation parameters. Studies in nonaqeous solvents were conducted with the free acid form of the mentioned carbarnates. Dimethylsulfoxide and chloroform were chosen as organic solvents for these particular experiments. The critical micellar concentrations of all surfactants were determined, and the assignment of the individual N-methyl peaks to the correspondend conformation could be unambiguously shown by a two dimensional NMR experiment. The cmc's show strong salt dependence. The effect of a lithium as an alternative counter ion has a less drastic effect. Micellization seems not to occur in the free acid cases. Interestingly, the surfactants show stronger salt dependence than micellization dependence upon the activation parameters, indicating that solvent exposure occurs at the C-N partial double bond and considerable deformation of the ideal spherical shape.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 119-136).

This thesis includes a summary of some of the early developments of M.IR and NQR detection. Elementary introduction to NQR detection is also discussed. Finally the construction of a high level NQR Spectrometer operating in the regenerative mode is treated. This regenerative spectrometer, originally designed by D. Sill, M. Hayek, Y. Alon, and A. Simievic and published in Rev. Sci. Instr. 38, 11 (1967), is discussed extensively.Ball State UniversityMuncie, IN 47306

The increase of calcium in the cell can induce cellular functions such as fertilization, cell division and cell communication. Calcium (Ca2+) carries out these processes through proteins called calcium sensors. An important calcium modulator is calmodulin. Calmodulin has four possible Ca2+ binding sites that have the characteristic helix-loop-helix (EF hand) motif. When the EF hands bind to Ca2+, methionine rich hydrophobic patches are exposed allowing for CaM to interact with target proteins. However, there are proteins that can interact with CaM at low levels of Ca2+ or in the absence of Ca2+. An enzyme that is activated by CaM is nitric oxide synthase (NOS), which converts L-arginine to L-citrulline and nitric oxide (•NO), where •NO is used to carry out important cellular functions. There are three isoforms of the enzyme; endothelial, neuronal and inducible NOS. The first two isoforms are activated by Ca2+-bound CaM when there is an influx of Ca2+ and are therefore Ca2+-dependent whereas inducible NOS (iNOS) is activated and binds tightly to CaM regardless of the Ca2+ concentration and is therefore Ca2+-independent. Of particular interest is the iNOS enzyme, since no three-dimensional structures of the reductase domain or the CaM-binding region have been solved. All three isoforms of NOS exist as homodimers, where each monomer consisting of a reductase domain and an oxygenase domain separated by a CaM-binding region. The reductase domain contains binding sites for NADPH and the flavins, FAD and FMN, which facilitate electron transfer from the NADPH to the catalytic heme in the oxygenase domain of the opposite monomer. The transfer of electrons from the FAD to the heme is carried out by the FMN domain which is proposed to swing between the two docking points since the distance between the two points is too large for electron transfer. This electron transfer point is under the control of CaM, which is essential for NOS activation. This dynamic process and the direct role of CaM have yet to be observed structurally. A method to monitor dynamics structurally is through the use of nuclear magnetic resonance (NMR) spectroscopy. Therefore as the first step to determine the NMR structure of the FMN domain with the CaM-binding region, the structure of the iNOS CaM-binding region bound to CaM will be determined. The structure will allow for further characterization and identification of important interactions between the iNOS CaM-binding region and CaM which contribute to the unique properties of iNOS.