• aldolases;
  • HHED aldolase homologue.

An ORF designated b2245 (yfaU) in the Escherichia coli K12 genome sequence, identified as an HHED aldolase homologue, was cloned into the high-expression plasmid pT7-7 and overexpressed in E. coli B835(DE3). The enzyme was purified in three steps to 95% purity prior to crystallization. Crystals were obtained by the hanging-drop vapour-diffusion method at 277 K from a number of screening conditions. Crystals suitable for structural studies were grown from solutions containing 0.4 M ammonium dihydrogen phosphate and grew to a maximum dimension of approximately 0.5 mm. Diffraction data to 1.7 Å were collected using an in-house Cu Kα radiation source at 100 K. The crystals belong to space group C2221, with unit-cell parameters a = 105.1, b = 136.6, c = 123.1 Å. A 90% complete data set was collected to 1.78 Å from a single native crystal using in-house facilities.