Asbjorn Hordvik

Crystallization and preliminary X-ray crystallographic studies of benzamidine-inhibited trypsin from the north atlantic salmon (Salmo salar)

Crystals of benzamidine-inhibited trypsin from the North Atlantic salmon (Salmo salar) have been grown from ammonium sulphate solution at pH 5.0. Two crystal forms suitable for X-ray structure analysis, obtained from a hanging-drop experiment, have been characterized. Both belong to space-group P22(1)2(1) with cell dimensions a = 39.2 A, b = 62.4 A, c = 84.6 A and a = 31.4 A, b = 74.8 A, c = 83.5 A, for forms I and II, respectively. Intensity data to 1.82 A have been collected for crystal form I on a CAD4 diffractometer, and initial phases have been obtained by molecular replacement methods. The conventional R-factor after two rounds of model building and subsequent refinement is 0.25 for data between 6.0 and 2.0 A. So far no water molecules have been included in the model.

S---S and S---O interactions in some 4-thiazoline derivatives

Abstract Structural data have been obtained by X-ray crystallography for three 4-thiazoline derivatives, 2-benzoylimino-3, 4-diphenyl-4-thiazoline, 3-methyl-4-phenyl-2-thiobenzoylimino-4-thiazoline, and 3,4-diphenyl-4-thiazolin-2-ylidene thioacetophenone. In these compounds the separations between the sulphur atoms of the thiazoline rings and the adjacent oxygen or sulphur atoms of the carbonyl or thiocarbonyl groups approximate to the Huggins “constant energy” distances, suggesting that there is little or no bonding between them.

CNDO/2 calculations on 6a-thiathiophthens; the effect of methyl and phenyl substituents on the sulphur–sulphur bonding

The effect of methyl and phenyl substituents on the sulphur–sulphur bonding in 6a-thiathiophthen can be described by the results from CNDO/2 calculations.

Crystal and molecular structure of D-threo-hexo-2,5-diulose; dimeric form in the solid state

In the crystalline state D-threo-hexo-2,5-diulose forms a dimer between a furanose form and a pyranose form of the sugar.

Crystallization and preliminary X-ray crystallographic studies of CO-hemoglobin from the North Atlantic salmon (Salmo salar)

Purification of hemoglobin from North Atlantic salmon (Salmo salar) gave three different types. The CO-complexes of types I and III have been crystallized by the batch method at 4 degrees C from solutions 18% (w/v) in polyethylene glycol 2000, 50 mg/ml in hemoglobin and 0.05 M in phosphate buffer (pH 8.3). Orthorhombic crystals, space group P2(1)2(1)2(1), were obtained for both, with cell dimensions a = 53.9 A, b = 80.4 A, c = 132.4 A, and a = 58.7 A, b = 95.0 A, c = 107.4 A, for types I and III, respectively.