High crystallography

Allan N L and W C Mackrodt 1997. High-T Superconductors in Computer Modelling. In Catlow C R A (Editor) Inorganic Crystallography, pp. 241-268. 

In superacidic media, the carbocationic iatermediates, which were long postulated to exist duting Friedel-Crafts type reactions (9—11) can be observed, and even isolated as salts. The stmctures of these carbocations have been studied ia high acidity—low nucleophilicity solvent systems usiag spectroscopic methods such as nmr, ir, Raman, esr, and x-ray crystallography. 

G Backes, Y Mino, TM Loehr, TE Meyer, MA Cusanovich, WV Sweeny, ET Adman, J Sand-ers-Loehr. The environment of Ee4S4 clusters in ferredoxms and high-potential iron proteins. New information from X-ray crystallography and resonance Raman spectroscopy. J Am Chem Soc 113 2055-2064, 1991. 

Biological fibers, such as can be formed by DNA and fibrous proteins, may contain crystallites of highly ordered molecules whose structure can in principle be solved to atomic resolution by x-ray crystallography. In practice, however, these crystallites are rarely as ordered as true crystals, and in order to locate individual atoms it is necessary to introduce stereochemical constraints in the x-ray analysis so that the structure can be refined by molecular modeling. 

During the past 20 y numerous other highly coloured halogen cations have been characterized by Raman spectroscopy. X-ray crystallography, and other techniques, as summarized in Table 17.18. Typical preparative routes involve direct oxidation of the halogen (a) in the absence of solvent, (b) in a solvent which is itself the oxidant (e.g. AsFs) or (c) in a non-reactive solvent (e.g. SO2). Some examples are listed below ... 

On the whole, the four main changes from the previous review (76AFICS1) have been (1) the standard application of high-level theoretical methods, (2) the massive use of X-ray crystallography, (3) the introduc-... 

X-ray structure of aequorin (Head et al., 2000). X-ray crystallography was performed with the recombinant aequorin prepared by the improved method described above. The crystals of recombinant aequorin were grown in a high concentration of ammonium sulfate. The results revealed that aequorin is a globular molecule containing a... 

Structural genomics is the systematic effort to gain a complete structural description of a defined set of molecules, ultimately for an organism s entire proteome. Structural genomics projects apply X-ray crystallography and NMR spectroscopy in a high-throughput manner. 

In the protein structure database PDB ( http //www. rcsb.org/pdb), by X-ray crystallography and NMR spectroscopy, experimentally solved 3D-protein structures are available to the public. Homology model building for a query sequence uses protein portions of known 3D-stmctures as structural templates for proteins with high sequence similarity. 

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