Nuclear magnetic resonance 2D NMR

For the investigation of the molecular dynamics in polymers, deuteron solid-state nuclear magnetic resonance (2D-NMR) spectroscopy has been shown to be a powerful method [1]. In the field of viscoelastic polymers, segmental dynamics of poly(urethanes) has been studied intensively by 2D-NMR [78, 79]. In addition to ID NMR spectroscopy, 2D NMR exchange spectroscopy was used to extend the time scale of molecular dynamics up to the order of milliseconds or even seconds. In combination with line-shape simulation, this technique allows one to obtain correlation times and correlation-time distributions of the molecular mobility as well as detailed information about the geometry of the motional process [1]. 

Two-dimensional nuclear magnetic resonance (2D NMR) techniques are the richest sources of structural information. They allow Eq. (5) to be formally expressed as... 

Abbreviations NMR, nuclear magnetic resonance 2D-NMR, two-dimensional NMR HOHAHA, 2D-NMR homonuclear Hartman-Hahn spectroscopy NOE, nuclear Overhauser effect NOESY, 2D-NMR nuclear Overhauser effect spectroscopy rf, radio frequency FID, free induction decay CD, circular dichroism PF4, platelet factor-4 IL-8, interleukin-8 Gro-a, growth-related protein a. 

Pathway calculations for the aforementioned intramolecular ET reaction were performed using the high-resolution 3D structures of P. aeruginosa azurin and its mutants, where available. For other mutants, structures based on two-dimensional nuclear magnetic resonance (2D NMR) studies and energy minimization calculations were employed. The pathway calculations predict similar ET routes in all the azurins shown in Fig. 4 One longer path through the peptide... 

Similarly to the isolation of LCC from wood, isolation of LCC from pulps can be performed using enzymatic hydrolysis. These preparations are usually called enzymatic residual lignins [46-49]. However, similarly to CEL, they contain significant amounts of LCC linkages proven by two-dimensional nuclear magnetic resonance (2D NMR) methods and therefore can be considered as LCC preparations [48,50,51]. Ball milling is not needed for the isolation of LCC from most chemical pulps, and as a result mechanical degradation can be avoided. 

Two dimensional Nuclear Magnetic Resonance (2D NMR) technique is facile and offers an easy handle to tackle problems involving structural elucidation of proteins in solution (55). Recently, we successfully employed this technique to study the solution structure (8,32,56) and protein folding (57) aspects of Cardiotoxin III from the Taiwan cobra. 

For our purpose, it is convenient to classify the measurements according to the format of the data produced. Sensors provide scalar valued quantities of the bulk fluid i. e. density p(t), refractive index n(t), viscosity dielectric constant e(t) and speed of sound Vj(t). Spectrometers provide vector valued quantities of the bulk fluid. Good examples include absorption spectra A t) associated with (1) far-, mid- and near-infrared FIR, MIR, NIR, (2) ultraviolet and visible UV-VIS, (3) nuclear magnetic resonance NMR, (4) electron paramagnetic resonance EPR, (5) vibrational circular dichroism VCD and (6) electronic circular dichroism ECD. Vector valued quantities are also obtained from fluorescence I t) and the Raman effect /(t). Some spectrometers produce matrix valued quantities M(t) of the bulk fluid. Here 2D-NMR spectra, 2D-EPR and 2D-flourescence spectra are noteworthy. A schematic representation of a very general experimental configuration is shown in Figure 4.1 where r is the recycle time for the system. 

Nuclear magnetic resonance (NMR) spectroscopy is a very powerful tool for analyzing the conformation and molecular architecture of carbohydrate molecules. Both one- and two-dimensional (ID and 2D) methodologies have provided valuable information about small and large molecules, ranging from the anomeric configuration of a monosaccharide to the sequence of monosaccharide residues that constitute an oligo- or polysaccharide. 

The possibilities of application of far-UV circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy in analysis of thermal stability of proteins and structural changes within protein molecules as well in explanation of cross reactivity between food allergens have been described in more detail in Section 3.4. Likewise nuclear magnetic resonance (NMR), especially 2D and multidimensional NMR as well as the method based on diffraction of monochromatic x-rays widely used in examination of tertiary structures of allergens have been described in Section 3.4 and by Neudecker et al. (2001) and Schirmer et al. (2005). 

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