X-ray crystallography and structure

QCFF/PI and PCILO calculations106, as well as a combined MM3, NMR X-ray crystallography and structure comparison study107-109, were used to identify biologically active... 

Wyatt PG, Woodhead AJ, Berdini V et al (2008) Identification of N-(4-piperidinyl)-4-(2,6-dichlorobenzoylamino)-lH-pyrazole-3-carboxamide (AT7519), a novel cyclin dependent kinase inhibitor using fragment-based X-ray crystallography and structure based drug design. J Med Chem 51 4986-4999... 

We have used a highly structure-driven approach composed of fragment-based NMR screening, X-ray crystallography, and structure-assisted chemistry to develop a first-in-class clinical candidate as a potential proof-of-concept for the inhibition of BACE-1 in AD. Crucial to this achievement was the initial identification of a ligand-efficient isothiourea fragment and its X-ray crystal structure, which revealed an extensive H-bond network with the two active site aspartates. This interaction was unprecedented in the aspartic acid protease field when we discovered it several... 

X-ray crystallography and structure of carbohydrates, 982, 985, 996 nucleic acids, 1094 proteins, 1084 vitamin B12, 568 X-rays, 488 m-Xylene, 406 nitration of, 472 o-Xylene, 406... 

The absolute configurations of two sorts of naturally occurring compounds have been determined by X-ray crystallography, and structures of synthetic compounds, all of which contain cyclopropane groups. Compound (4) has been reported as a bisnorcaradiene with a particularly long C-1—C-6 bond (1.80 A). This non-aromatic structure for (4) corroborates earlier n.m.r. work. The cyclopropene moiety of the benzocyclopropene (5) has been shown ... 

The initial coordinates r(0) are usually obtained from experimentally determined molecular structures, mainly from X-ray crystallography and NMR experiments. Alternatively, the initial coordinates can be based on computer models generated by a variety of modeling techniques (see Chapters 14 and 15). Note, however, that even the experimentally determined strucmres must often undergo some preparation steps before they can be used as initial structures in a dynamic simulation. 

Kallen, J., et al. Structure of human cyclophilin and its binding site for cyclosporin A determined by x-ray crystallography and NMR spectroscopy. Nature 353 276-279, 1991. 

The three-dimensional structure of protein molecules can be experimentally determined by two different methods, x-ray crystallography and NMR. The interaction of x-rays with electrons in molecules arranged in a crystal is used to obtain an electron-density map of the molecule, which can be interpreted in terms of an atomic model. Recent technical advances, such as powerful computers including graphics work stations, electronic area detectors, and... 

Organic thionylamines have planar, cis structures (9.9) in the solid state and in solution, as determined by X-ray crystallography and N NMR spectroscopy, respectively. The gas-phase structures of the parent compound HNSO and MeNSO have been determined by microwave spectroscopy. The S=N and S=0 double bond lengths are 1.51-1.52 and 1.45-1.47 A, respectively. The bond angle [Pg.168]

Recent extensive structural studies by X-ray crystallography and by P nmr spectroscopy have revealed an astonishing variety of con/imcto-polyphosphides with quasi-ionic... 

The structure of human muscle fructose-1,6-bisphosphate aldolase, as determined by X-ray crystallography and downloaded from the Protein Data Bank. (PDB ID 1ALD Gamblin, S. J., Davies, G. J., Grimes, J. M., Jackson, R. M., Littlechild, J. A., Watson, H. C. Activity and specificity of human aldolases. J. Mol. Biol. v219, pp. 573-576, 1991.)... 

More detailed aspects of protein function can be obtained also by force-field based approaches. Whereas protein function requires protein dynamics, no experimental technique can observe it directly on an atomic scale, and motions have to be simulated by molecular dynamics (MD) simulations. Also free energy differences (e.g. between binding energies of different protein ligands) can be characterised by MD simulations. Molecular mechanics or molecular dynamics based approaches are also necessary for homology modelling and for structure refinement in X-ray crystallography and NMR structure determination. 

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. 

The concentration of this species in liquid sulfur was estimated from the calculated Gibbs energy of formation as ca. 1% of all Ss species at the boihng point [35]. In this context it is interesting to note that the structurally related homocyclic sulfur oxide Sy=0 is known as a pure compound and has been characterized by X-ray crystallography and vibrational spectroscopy [48, 49]. Similarly, branched long chains of the type -S-S-S(=S)-S-S- must be components of the polymeric S o present in liquid sulfur at higher temperatures since the model compound H-S-S-S(=S)-S-S-H was calculated to be by only 53 kJ mol less stable at the G3X(MP2) level than the unbranched helical isomer of HySs [35]. 

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