Thermodynamic analysis and experimental demonstration of β-Ga2O3 growth by metalorganic vapor phase epitaxy using triethylgallium (TEG) and oxygen (O2) precursors were performed. Thermodynamic analysis revealed that the O2 supplied is preferentially used for the combustion of hydrocarbons and H2 derived from TEG. Therefore, the use of high growth temperatures and high input VI/III ratios is essential for the complete combustion of hydrocarbons and H2, and β-Ga2O3 growth. The use of an inert gas as the carrier gas was also determined as necessary to grow β-Ga2O3 at high temperatures. Based on these results, a ( 2 ¯ 01) oriented smooth β-Ga2O3 layer could be grown on a c-plane sapphire substrate at 900 °C with a growth rate of 1.4 μm h−1 at an input VI/III ratio of 100. The grown layer showed a clear optical bandgap of 4.84 eV, and impurity concentrations of hydrogen and carbon were below the background levels of the measurement system.

are necessary for the uridylylation of Pn by UTase!UR.In order to elucidate the potential structural changes which may occur upon ligand binding, Pn has been crystallised with a number of effector ligands including 2-ketoglutarate (2-KG), glutamate and ATP, and ATP in combination with 2-ketoglutarate and glutamate. We anticipate that these structure determinations will provide us with new insights into the way Pn influences the enzymes involved in nitrogen regulation and how its interaction with various ligands plays a crucial role in signal transduction.A molecular replacement solution for the Pn/ ATP/2-KG crystals has been obtained and refinement of the structure is in progress. Details of the crystallisation, structure solution and cmTent model will be presented.

Cryogenic data collection for macromolecular crystals is increasing in popularity as a means of improving data quality. The advantages include the postponement of radiation damage. elimination of eiTors arising from inter-crystal scaling and merging, reduced thermal motion, enhanced contrast in electron density maps, and a possible reduction in conformational disorder. Crystals ar•e generally cooled after modification of the aqueous layer surrounding the surface of the crystal, either by some antifreeze (cryoprotectant) or oil. When a crystal is sufficiently robust that it can survive cooling by being placed directly in a cold gas stream, that should be the cooling method of choice. Often. however, successful crystal cooling requires that the cooling operation be

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