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 P22121 with cell dimensions a = 39.2 Å, b = 62.4 Å, c = 84.6 Åanda = 31.4 Å, b = 74.8 Å, c = 83.5 Å, for forms I and II, respectively. Intensity data to 1.82 Åhave 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 Å. So far no water molecules have been included in the model. © 1990 Academic Press Limited.