Crystallization and preliminary X-ray diffraction studies of a-amylase from the antarctic psychrophile Alteromonas haloplanctis A23

A cold-active alpha-amylase was purified from culture supernatants of the antarctic psychrophile Alteromonas haloplanctis A23 grown at 4 degrees C. In order to contribute to the understanding of the molecular basis of cold adaptations, crystallographic studies of this cold-adapted enzyme have been initiated because a three-dimensional structure of a mesophilic counterpart, pig pancreatic alpha-amylase, already exists. alpha-Amylase from A. haloplanctis, which shares 53% sequence identity with pig pancreatic alpha-amylase, has been crystallized and data to 1.85 A have been collected. The space group is found to be C222(1) with a = 71.40 A, b = 138.88 A, and c = 115.66 A. Until now, a three-dimensional structure of a psychrophilic enzyme is lacking.