Molecular structure of taka-amylase A. I. Backbone chain folding at 3 A resolution.

The crystal structure of Taka-amylase A was studied by an X-ray diffraction method at 3 A resolution. A total of 452 amino acid residues were found from the electron density map at the present stage. The four disulfide bonds and the branched carbohydrate were also located on the map. The difference electron density map of the maltotriose-soaked crystal showed that a maltose unit was bound in the active center left. The binding of iodine atoms to the enzyme was also studied.