Nuclear magnetic resonance spectroscop three-dimensional

Structural investigations into the degree of branching and into the position and nature of glycosidic bonds and of non-carbohydrate residues in polysaccharides may include periodate oxidation and other procedures such as exhaustive methylation. X-ray diffraction and spectroscopic techniques such as nuclear magnetic resonance and optical rotatory dispersion also give valuable information especially relating to the three-dimensional structures of these polymers. 

Aside from the direct techniques of X-ray or electron diffraction, the major possible routes to knowledge of three-dimensional protein structure are prediction from the amino acid sequence and analysis of spectroscopic measurements such as circular dichroism, laser Raman spectroscopy, and nuclear magnetic resonance. With the large data base now available of known three-dimensional protein structures, all of these approaches are making considerable progress, and it seems possible that within a few years some combination of noncrystallo-graphic techniques may be capable of correctly determining new protein structures. Because the problem is inherently quite difficult, it will undoubtedly be essential to make the best possible use of all hints available from the known structures. 

Nuclear magnetic resonance (NMR) spectroscopy is a nonin-vasive and nondestructive spectroscopic technique that allows determination of the constitution and relative configuration of molecules, the characterization of the dynamic three-dimensional (3D) conformation of molecules, and their interaction with other molecules. NMR spectroscopy detects the characteristics of nuclear spins the most commonly studied nuclei are the spin-i/z-particles H, N, and NMR observables... 

It is now accepted that the proper expression of hormone activity depends on the conformation of the peptide. Unfortunately, the conformation of peptides of 20 or more amino acids, which are the subject of this chapter, cannot easily be determined by spectroscopic methods, such as nuclear magnetic resonance, which have been used successfully for some smaller peptides. Crystallization of some of these molecules, however, has allowed the determination, using single-crystal X-ray diffraction, of their three-dimensional structures. These have been related to the solution structures by comparing the circular dichroism and nuclear magnetic resonance spectra measured in... 

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