Crystal analysis

Use of a fusion protein to obtain crystals suitable for X-ray analysis crystallization of a GST-fused protein containing the DNA-binding domain of DNA replication-related element-binding factor, DREE Protein Sci 6 ... 

Glasgow, J., Fortier, S. and Allen, F. (1993). Molecular scene analysis crystal structure determination through imagery. In Hunter, L., ed. Artificial Intelligence and Molecular Biology. MIT Press, Cambridge, MA. 

These findings were confirmed (29, 30) by demonstrating the coexistence of C-20 epimers in the same crystal of veatchine by a single-crystal X-ray analysis. Crystallization of two epimers in a disordered relationship is a highly unusual observation. Even though veatchine exists as a mixture of... 

The structure of the first silylhydrazine four-membered ring has been confirmed by X-ray analysis. Crystals suitable for X-ray analysis were obtained after a 2-week crystallization process by slowly condensing the "-hexane solvent in an ice-cooled trap. Figure 8 shows the result of the X-ray analysis of 116. 

Cold Test. The ability of an oil to withstand refrigerator storage is determined by the cold test analysis crystallization resistance is measured as the time in hours before the oil appears cloudy at 32°F or 0°C. Standardized AOCS Method Cc 11-53 requires that dry filtered oil be placed in a sealed 4-ounce bottle and submerged into an ice bath (103). A go/no-go examination after 5.5 hours for clarity is stipulated by the Official AOCS Method however, most laboratories practice the alternative procedure, which continues the clarity examinations until a cloud... 

For protein crystal structure analysis, crystals of at least 0.3 mm in dimension are required. With the introduction of the intense synchrotron radiation source (Section 3(d)) this value may be reduced to 0.1 mm. Crystallisation may be divided into three steps (a) supersaturation of the protein solution (b) crystal nucleation (c) post-nucleation growth and cessation of growth. In the following sub-sections these steps are considered briefly. Previous reviews [25,31] contain greater detail. I am indebted to M.S.P. Sansom [32] for the clear summary presented in his thesis. 

Alternatively, one can use sitting drop vapor diffusion where the drop is placed in a raised depression within the well. The sitting drop vapor diffusion experiment requires special plates or devices but set-up and retrieval of crystals is much simpler. Once the plate is prepared, it is then incubated at either 4 or 18°C for a period of time ranging from a few days to weeks. During incubation, each well of the plate is checked periodically under a microscope for the presence of crystals or precipitate. Conditions derived from the initial screen are usually further refined by adjusting pH, additives, and concentrations to grow suitable crystals for data collection and structnre analysis. Crystal seeding (Stura et al., 1992) can also be explored to improve the crystal size and quality. 

Three samples synthesised under various conditions and containing (Al,Sb,V)204 were selected for elemental analysis. Crystals of (Al,Sb,V)204 in each sample were first identified by electron diffraction and were then analysed using EDX. The data are plotted in Fig. 6. 

Characterization. Actinide metal samples for the determination of properties related to bonding have to be characterized for chemical purity and phase homogeneity. Purity is checked by chemical or physical analysis, crystal structure is determined by X-ray or neutron diffraction techniques phase heterogeneities can be observed by metallography. 

Our complementary approach combines the analysis of the crystal structure with analysis of the molecular structure of the component systems, using experimental data from X-ray crystal analysis, crystal packing studies, extended Hiickel and density functional calculations, as described above. 

To test this strategy further, we prepared and cocrystallized another pair of sulfoxides, (5)-(6a) and (i )-(6b). These crystals were again suitable for singlecrystal analysis. Crystal data appear in Table 6 and the packing diagram is... 

From the chemical point of view it seems to be of particular interest that further (metastable) tellurium subhalides can be obtained by hydrothermal syntheses in acid solutions. In the hydrothermal work on the crystal growth of arsenic telluro-iodides a pure binary tellurium subiodide with the composition Tcsl was obtained as well as a ternary phase with only small amounts of arsenic (AsT Ij The composition Tejl was checked by chemical as well as energy-dispersive X-ray analysis. Crystals of the new tellurium subiodide are shown in Fig. 43 a crystal structure analysis failed because the quality of the crystals was not suitable for single crystal investigation. During annealing of the subiodide a stable phase combination a-Tel -H Te was formed which indicated the metastable character of TesL... 

PUS] Amorphous ribbons B-Cr-Fe, 10 and 15 at.% Cr, 15 at.% B, after annealing in air at atmospheric and low pressure and temperatures from 300 to 350°C were examined with Mdssbauer spectroscopy and Auger analysis. Crystallization of the amorphous samples and formation of oxides were studied. 

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