THE INVESTIGATION OF CRYSTALS OF THE COMP LEX ASPARTATE-AMINOTRANSFERASE WITH D-ASPARTATE

We report here the x-ray studies of the complex cytosolic aspartate am inotransferase from chicken heart with D-aspartate at 2,7 angstrom res olution. Crystals of the complex was prepared by diffusing D-aspartate into free enzyme crystals; their space group is P 2(1)2(1)2(1) with c ell dimensions (angstrom): a = 62,59; b = 117,83; c = 124,38. They con tain one dimeric molecule in the asymmetric unit. The x-ray crystallog raphic analysis proves that the connection of the D-aspartate induces small conformational changes in the active site of two subunits of the enzyme: considerable conformational changes are determined for His 18 9, Phe 360, Tyr 70, Arg 292, Phe 18 and Glu 141.