LOW RESOLUTION CRYSTAL-STRUCTURES OF TAKA-AMYLASE-A AND ITS COMPLEXES WITH INHIBITORS

The molecular structure of Taka-amylase A, an α-amylase from Aspergillus oryzae, has been studied at 6 Á resolution by X-ray diffraction analysis. The electron density map showed a non-crystallographic three-fold screw arrangement of the molecules in the crystal. The molecule is an ellipsoid with approximate dimensions of 80 × 45 × 35 Á and contains a hollow which may correspond to the active center. The inhibitor molecules bind to Taka-amylase A at four different sites, one of which is located in the hollow of the enzyme. The probable position of a thiol group is discussed in connection with heavy atom binding. © 1979, by the Japanese Biochemical Society.