Polymorphous crystallization and diffraction of threonine deaminase from Escherichia coli

The biosynthetic threonine deaminase from Escherichia coli, an allosteric tetramer with key regulatory functions, has been crystallized in several crystal forms. Two distinct forms, both belonging to either space group P3₁21 or P3₂21, with different sized asymmetric units that both contain a tetramer, grow under identical conditions. Diffraction data sets to 2.8 Å resolution (native) and 2.9 Å resolution (isomorphous uranyl derivative) have been collected from a third crystal form in space group I222.